Thread 79 (Thread 0x14ac4f22b700 (LWP 3958867)):
#0  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:78
#1  0x000014ac55ab3530 in ?? () at allocatestack.c:311 from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x000014ac4f22b700 in ?? ()
#3  0x0000000000000000 in ?? ()

Thread 78 (Thread 0x14ac4f02a700 (LWP 3958868)):
#0  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:78
#1  0x000014ac55ab3530 in ?? () at allocatestack.c:311 from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x000014ac4f02a700 in ?? ()
#3  0x0000000000000000 in ?? ()

Thread 77 (Thread 0x14ac4e424700 (LWP 3958875)):
#0  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:78
#1  0x000014ac55ab3530 in ?? () at allocatestack.c:311 from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x000014ac4e424700 in ?? ()
#3  0x0000000000000000 in ?? ()

Thread 76 (Thread 0x14ac4de21700 (LWP 3958878)):
#0  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:78
#1  0x000014ac55ab3530 in ?? () at allocatestack.c:311 from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x000014ac4de21700 in ?? ()
#3  0x0000000000000000 in ?? ()

Thread 75 (Thread 0x14ac5231f700 (LWP 3958841)):
#0  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:78
#1  0x000014ac55ab3530 in ?? () at allocatestack.c:311 from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x000014ac5231f700 in ?? ()
#3  0x0000000000000000 in ?? ()

Thread 74 (Thread 0x14ac54e3b700 (LWP 3958829)):
#0  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:78
#1  0x000014ac55ab3530 in ?? () at allocatestack.c:311 from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x000014ac54e3b700 in ?? ()
#3  0x0000000000000000 in ?? ()

Thread 73 (Thread 0x14ac4ee29700 (LWP 3958870)):
#0  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:78
#1  0x000014ac55ab3530 in ?? () at allocatestack.c:311 from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x000014ac4ee29700 in ?? ()
#3  0x0000000000000000 in ?? ()

Thread 72 (Thread 0x14ac51f1d700 (LWP 3958844)):
#0  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:78
#1  0x000014ac55ab3530 in ?? () at allocatestack.c:311 from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x000014ac51f1d700 in ?? ()
#3  0x0000000000000000 in ?? ()

Thread 71 (Thread 0x14ac50032700 (LWP 3958859)):
#0  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:78
#1  0x000014ac55ab3530 in ?? () at allocatestack.c:311 from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x000014ac50032700 in ?? ()
#3  0x0000000000000000 in ?? ()

Thread 70 (Thread 0x14ac4ea27700 (LWP 3958872)):
#0  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:78
#1  0x000014ac55ab3530 in ?? () at allocatestack.c:311 from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x000014ac4ea27700 in ?? ()
#3  0x0000000000000000 in ?? ()

Thread 69 (Thread 0x14ac4f42c700 (LWP 3958866)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac4f42bd40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb34a0c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac4f42bd40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb349e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb349e0, mutex=0x5563bcb26850, abstime=0x14ac4f42bd40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac4f42bd40, __mutex=<optimized out>, __cond=0x5563bcb349e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb349e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb349e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb349e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb349e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb349e0, t=0x14ac4f42bde8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb349e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 68 (Thread 0x14ac52b23700 (LWP 3958837)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac52b22d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35788) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac52b22d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35760) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35760, mutex=0x5563bcb26850, abstime=0x14ac52b22d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac52b22d40, __mutex=<optimized out>, __cond=0x5563bcb35760) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35760) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35760) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35760) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35760) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35760, t=0x14ac52b22de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35760) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 67 (Thread 0x14ac331d4700 (LWP 3928883)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac331d3d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb3638c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac331d3d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb36360) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb36360, mutex=0x5563bcb26850, abstime=0x14ac331d3d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac331d3d40, __mutex=<optimized out>, __cond=0x5563bcb36360) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb36360) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb36360) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb36360) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb36360) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb36360, t=0x14ac331d3de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb36360) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 66 (Thread 0x14ac50434700 (LWP 3958857)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac50433d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb34e08) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac50433d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb34de0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb34de0, mutex=0x5563bcb26850, abstime=0x14ac50433d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac50433d40, __mutex=<optimized out>, __cond=0x5563bcb34de0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb34de0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb34de0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb34de0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb34de0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb34de0, t=0x14ac50433de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb34de0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 65 (Thread 0x14ac52520700 (LWP 3958840)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac5251fd40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35608) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac5251fd40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb355e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb355e0, mutex=0x5563bcb26850, abstime=0x14ac5251fd40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac5251fd40, __mutex=<optimized out>, __cond=0x5563bcb355e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb355e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb355e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb355e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb355e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb355e0, t=0x14ac5251fde8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb355e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 64 (Thread 0x14ac5503c700 (LWP 3958828)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac5503bd40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35c08) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac5503bd40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35be0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35be0, mutex=0x5563bcb26850, abstime=0x14ac5503bd40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac5503bd40, __mutex=<optimized out>, __cond=0x5563bcb35be0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35be0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35be0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35be0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35be0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35be0, t=0x14ac5503bde8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35be0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 63 (Thread 0x14ac30b52700 (LWP 3928968)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac30b51d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35c8c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac30b51d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35c60) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35c60, mutex=0x5563bcb26850, abstime=0x14ac30b51d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac30b51d40, __mutex=<optimized out>, __cond=0x5563bcb35c60) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35c60) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35c60) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35c60) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35c60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35c60, t=0x14ac30b51de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35c60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 62 (Thread 0x14ac4f62d700 (LWP 3958865)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac4f62cd40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb34a88) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac4f62cd40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb34a60) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb34a60, mutex=0x5563bcb26850, abstime=0x14ac4f62cd40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac4f62cd40, __mutex=<optimized out>, __cond=0x5563bcb34a60) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb34a60) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb34a60) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb34a60) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb34a60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb34a60, t=0x14ac4f62cde8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb34a60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 61 (Thread 0x14ac4fa2f700 (LWP 3958863)):
#0  __lll_lock_wait (futex=futex@entry=0x5563bb708440 <buf_pool>, private=0) at lowlevellock.c:52
#1  0x000014ac55ab60a3 in __GI___pthread_mutex_lock (mutex=mutex@entry=0x5563bb708440 <buf_pool>) at ../nptl/pthread_mutex_lock.c:80
#2  0x00005563bad0a73d in inline_mysql_mutex_lock (that=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/include/mysql/psi/mysql_thread.h:752
#3  buf_page_write_complete (request=...) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/buf/buf0flu.cc:405
#4  0x00005563bad428f0 in fil_aio_callback (request=...) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/fil/fil0fil.cc:2874
#5  0x00005563bac2f136 in io_callback (cb=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/os/os0file.cc:3556
#6  0x00005563bad9d019 in tpool::task_group::execute (this=0x5563bcb6b590, t=0x14ac4ce06b40) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/task_group.cc:55
#7  0x00005563bad9bda7 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb34b60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:588
#8  0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#9  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#10 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 60 (Thread 0x14ac30906700 (LWP 3931858)):
#0  __libc_send (flags=<optimized out>, len=62, buf=0x14abd05a8318, fd=43) at ../sysdeps/unix/sysv/linux/send.c:28
#1  __libc_send (fd=43, buf=buf@entry=0x14abd05a8318, len=len@entry=62, flags=flags@entry=64) at ../sysdeps/unix/sysv/linux/send.c:23
#2  0x00005563baac96be in inline_mysql_socket_send (flags=64, n=62, buf=0x14abd05a8318, mysql_socket=...) at /test/preview-10.10-MDEV-16329-online-alter_opt/include/mysql/psi/mysql_socket.h:849
#3  vio_write (vio=0x14abd0008288, buf=0x14abd05a8318 ":", size=62) at /test/preview-10.10-MDEV-16329-online-alter_opt/vio/viosocket.c:267
#4  0x00005563baa944c6 in net_real_write (net=net@entry=0x14abd0000f08, packet=0x14abd05a8318 ":", len=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/net_serv.cc:722
#5  0x00005563baa94787 in net_flush (net=net@entry=0x14abd0000f08) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/net_serv.cc:402
#6  0x00005563baa94ef1 in net_write_command (net=net@entry=0x14abd0000f08, command=command@entry=255 '\377', header=header@entry=0x5563bb0fc224 "", head_len=<optimized out>, head_len@entry=0, packet=0x14ac30905110 "p\004#21S01Broj kolona ne odgovara broju vrednosti u slogu 1", len=57) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/net_serv.cc:550
#7  0x00005563ba63cac0 in Protocol::net_send_error_packet (this=<optimized out>, thd=0x14abd0000c58, sql_errno=1136, err=<optimized out>, sqlstate=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/protocol.cc:475
#8  0x00005563ba63dc1b in Protocol::send_error (sql_state=<optimized out>, err_msg=<optimized out>, sql_errno=<optimized out>, this=0x14abd00011d8) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/protocol.cc:671
#9  Protocol::end_statement (this=0x14abd00011d8) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/protocol.cc:596
#10 0x00005563ba70a1ad in dispatch_command (command=COM_QUERY, thd=0x14abd0000c58, packet=<optimized out>, packet_length=<optimized out>, blocking=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/sql_parse.cc:2401
#11 0x00005563ba70cd82 in do_command (thd=0x14abd0000c58, blocking=blocking@entry=true) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/sql_parse.cc:1407
#12 0x00005563ba823e7f in do_handle_one_connection (connect=<optimized out>, connect@entry=0x5563bce20798, put_in_cache=put_in_cache@entry=true) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/sql_connect.cc:1418
#13 0x00005563ba82415d in handle_one_connection (arg=0x5563bce20798) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/sql_connect.cc:1312
#14 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#15 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 59 (Thread 0x14ac31557700 (LWP 3928963)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac31556d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35f0c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac31556d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35ee0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35ee0, mutex=0x5563bcb26850, abstime=0x14ac31556d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac31556d40, __mutex=<optimized out>, __cond=0x5563bcb35ee0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35ee0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35ee0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35ee0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35ee0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35ee0, t=0x14ac31556de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35ee0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 58 (Thread 0x14ac5103a700 (LWP 3958851)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac51039d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35108) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac51039d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb350e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb350e0, mutex=0x5563bcb26850, abstime=0x14ac51039d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac51039d40, __mutex=<optimized out>, __cond=0x5563bcb350e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb350e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb350e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb350e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb350e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb350e0, t=0x14ac51039de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb350e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 57 (Thread 0x14ac50a37700 (LWP 3958854)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac50a36d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb34f8c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac50a36d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb34f60) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb34f60, mutex=0x5563bcb26850, abstime=0x14ac50a36d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac50a36d40, __mutex=<optimized out>, __cond=0x5563bcb34f60) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb34f60) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb34f60) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb34f60) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb34f60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb34f60, t=0x14ac50a36de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb34f60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 56 (Thread 0x14ac4fc30700 (LWP 3958861)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac4fc2fd40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb34c0c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac4fc2fd40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb34be0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb34be0, mutex=0x5563bcb26850, abstime=0x14ac4fc2fd40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac4fc2fd40, __mutex=<optimized out>, __cond=0x5563bcb34be0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb34be0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb34be0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb34be0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb34be0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb34be0, t=0x14ac4fc2fde8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb34be0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 55 (Thread 0x14ac4f82e700 (LWP 3958864)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac4f82dd40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb34b08) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac4f82dd40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb34ae0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb34ae0, mutex=0x5563bcb26850, abstime=0x14ac4f82dd40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac4f82dd40, __mutex=<optimized out>, __cond=0x5563bcb34ae0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb34ae0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb34ae0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb34ae0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb34ae0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb34ae0, t=0x14ac4f82dde8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb34ae0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 54 (Thread 0x14ac31e0c700 (LWP 3928903)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac31e0bd40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb36008) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac31e0bd40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35fe0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35fe0, mutex=0x5563bcb26850, abstime=0x14ac31e0bd40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac31e0bd40, __mutex=<optimized out>, __cond=0x5563bcb35fe0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35fe0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35fe0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35fe0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35fe0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35fe0, t=0x14ac31e0bde8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35fe0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 53 (Thread 0x14ac52922700 (LWP 3958838)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac52921d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb3570c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac52921d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb356e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb356e0, mutex=0x5563bcb26850, abstime=0x14ac52921d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac52921d40, __mutex=<optimized out>, __cond=0x5563bcb356e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb356e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb356e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb356e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb356e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb356e0, t=0x14ac52921de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb356e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 52 (Thread 0x14ac5123b700 (LWP 3958850)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac5123ad40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35188) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac5123ad40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35160) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35160, mutex=0x5563bcb26850, abstime=0x14ac5123ad40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac5123ad40, __mutex=<optimized out>, __cond=0x5563bcb35160) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35160) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35160) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35160) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35160) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35160, t=0x14ac5123ade8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35160) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 51 (Thread 0x14ac30f54700 (LWP 3928966)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac30f53d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35d88) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac30f53d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35d60) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35d60, mutex=0x5563bcb26850, abstime=0x14ac30f53d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac30f53d40, __mutex=<optimized out>, __cond=0x5563bcb35d60) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35d60) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35d60) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35d60) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35d60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35d60, t=0x14ac30f53de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35d60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 50 (Thread 0x14ac50c38700 (LWP 3958853)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac50c37d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35008) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac50c37d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb34fe0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb34fe0, mutex=0x5563bcb26850, abstime=0x14ac50c37d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac50c37d40, __mutex=<optimized out>, __cond=0x5563bcb34fe0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb34fe0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb34fe0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb34fe0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb34fe0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb34fe0, t=0x14ac50c37de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb34fe0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 49 (Thread 0x14ac51518700 (LWP 3958849)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac51517d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35208) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac51517d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb351e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb351e0, mutex=0x5563bcb26850, abstime=0x14ac51517d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac51517d40, __mutex=<optimized out>, __cond=0x5563bcb351e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb351e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb351e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb351e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb351e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb351e0, t=0x14ac51517de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb351e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 48 (Thread 0x14ac4e625700 (LWP 3958874)):
#0  __lll_lock_wait (futex=futex@entry=0x5563bcb26850, private=0) at lowlevellock.c:52
#1  0x000014ac55ab807b in __pthread_mutex_cond_lock (mutex=mutex@entry=0x5563bcb26850) at ../nptl/pthread_mutex_lock.c:80
#2  0x000014ac55aba699 in __pthread_cond_wait_common (abstime=0x14ac4e624d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb34660) at pthread_cond_wait.c:636
#3  __pthread_cond_timedwait (cond=0x5563bcb34660, mutex=0x5563bcb26850, abstime=0x14ac4e624d40) at pthread_cond_wait.c:665
#4  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac4e624d40, __mutex=<optimized out>, __cond=0x5563bcb34660) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#5  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb34660) at /usr/include/c++/9/condition_variable:188
#6  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb34660) at /usr/include/c++/9/condition_variable:121
#7  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb34660) at /usr/include/c++/9/condition_variable:152
#8  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb34660) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#9  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb34660, t=0x14ac4e624de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#10 0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb34660) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#11 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#12 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#13 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 47 (Thread 0x14ac54c3a700 (LWP 3958830)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac54c39d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35b08) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac54c39d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35ae0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35ae0, mutex=0x5563bcb26850, abstime=0x14ac54c39d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac54c39d40, __mutex=<optimized out>, __cond=0x5563bcb35ae0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35ae0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35ae0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35ae0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35ae0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35ae0, t=0x14ac54c39de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35ae0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 46 (Thread 0x14ac51719700 (LWP 3958848)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac51718d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35288) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac51718d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35260) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35260, mutex=0x5563bcb26850, abstime=0x14ac51718d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac51718d40, __mutex=<optimized out>, __cond=0x5563bcb35260) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35260) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35260) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35260) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35260) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35260, t=0x14ac51718de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35260) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 45 (Thread 0x14ac50836700 (LWP 3958855)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac50835d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb34f0c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac50835d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb34ee0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb34ee0, mutex=0x5563bcb26850, abstime=0x14ac50835d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac50835d40, __mutex=<optimized out>, __cond=0x5563bcb34ee0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb34ee0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb34ee0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb34ee0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb34ee0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb34ee0, t=0x14ac50835de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb34ee0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 44 (Thread 0x14ac3240f700 (LWP 3928900)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac3240ed40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb3618c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac3240ed40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb36160) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb36160, mutex=0x5563bcb26850, abstime=0x14ac3240ed40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac3240ed40, __mutex=<optimized out>, __cond=0x5563bcb36160) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb36160) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb36160) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb36160) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb36160) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb36160, t=0x14ac3240ede8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb36160) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 43 (Thread 0x14ac50635700 (LWP 3958856)):
#0  __lll_lock_wait (futex=futex@entry=0x5563bb708440 <buf_pool>, private=0) at lowlevellock.c:52
#1  0x000014ac55ab60a3 in __GI___pthread_mutex_lock (mutex=mutex@entry=0x5563bb708440 <buf_pool>) at ../nptl/pthread_mutex_lock.c:80
#2  0x00005563bad0a73d in inline_mysql_mutex_lock (that=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/include/mysql/psi/mysql_thread.h:752
#3  buf_page_write_complete (request=...) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/buf/buf0flu.cc:405
#4  0x00005563bad428f0 in fil_aio_callback (request=...) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/fil/fil0fil.cc:2874
#5  0x00005563bac2f136 in io_callback (cb=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/os/os0file.cc:3556
#6  0x00005563bad9d019 in tpool::task_group::execute (this=0x5563bcb6b590, t=0x14ac4ce0ad28) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/task_group.cc:55
#7  0x00005563bad9bda7 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb34e60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:588
#8  0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#9  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#10 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 42 (Thread 0x14ac4fe31700 (LWP 3958860)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac4fe30d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb34c8c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac4fe30d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb34c60) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb34c60, mutex=0x5563bcb26850, abstime=0x14ac4fe30d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac4fe30d40, __mutex=<optimized out>, __cond=0x5563bcb34c60) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb34c60) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb34c60) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb34c60) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb34c60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb34c60, t=0x14ac4fe30de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb34c60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 41 (Thread 0x14ac52d24700 (LWP 3958836)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac52d23d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb3580c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac52d23d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb357e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb357e0, mutex=0x5563bcb26850, abstime=0x14ac52d23d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac52d23d40, __mutex=<optimized out>, __cond=0x5563bcb357e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb357e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb357e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb357e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb357e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb357e0, t=0x14ac52d23de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb357e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 40 (Thread 0x14ac53126700 (LWP 3958834)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac53125d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35908) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac53125d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb358e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb358e0, mutex=0x5563bcb26850, abstime=0x14ac53125d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac53125d40, __mutex=<optimized out>, __cond=0x5563bcb358e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb358e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb358e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb358e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb358e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb358e0, t=0x14ac53125de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb358e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 39 (Thread 0x14ac5211e700 (LWP 3958843)):
#0  __lll_lock_wait (futex=futex@entry=0x5563bcb26850, private=0) at lowlevellock.c:52
#1  0x000014ac55ab807b in __pthread_mutex_cond_lock (mutex=mutex@entry=0x5563bcb26850) at ../nptl/pthread_mutex_lock.c:80
#2  0x000014ac55aba699 in __pthread_cond_wait_common (abstime=0x14ac5211dd40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb354e0) at pthread_cond_wait.c:636
#3  __pthread_cond_timedwait (cond=0x5563bcb354e0, mutex=0x5563bcb26850, abstime=0x14ac5211dd40) at pthread_cond_wait.c:665
#4  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac5211dd40, __mutex=<optimized out>, __cond=0x5563bcb354e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#5  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb354e0) at /usr/include/c++/9/condition_variable:188
#6  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb354e0) at /usr/include/c++/9/condition_variable:121
#7  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb354e0) at /usr/include/c++/9/condition_variable:152
#8  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb354e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#9  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb354e0, t=0x14ac5211dde8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#10 0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb354e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#11 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#12 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#13 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 38 (Thread 0x14ac5191a700 (LWP 3958847)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac51919d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35308) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac51919d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb352e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb352e0, mutex=0x5563bcb26850, abstime=0x14ac51919d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac51919d40, __mutex=<optimized out>, __cond=0x5563bcb352e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb352e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb352e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb352e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb352e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb352e0, t=0x14ac51919de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb352e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 37 (Thread 0x14ac50233700 (LWP 3958858)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac50232d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb34d8c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac50232d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb34d60) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb34d60, mutex=0x5563bcb26850, abstime=0x14ac50232d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac50232d40, __mutex=<optimized out>, __cond=0x5563bcb34d60) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb34d60) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb34d60) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb34d60) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb34d60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb34d60, t=0x14ac50232de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb34d60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 36 (Thread 0x14ac51b1b700 (LWP 3958846)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac51b1ad40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35388) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac51b1ad40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35360) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35360, mutex=0x5563bcb26850, abstime=0x14ac51b1ad40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac51b1ad40, __mutex=<optimized out>, __cond=0x5563bcb35360) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35360) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35360) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35360) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35360) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35360, t=0x14ac51b1ade8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35360) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 35 (LWP 3958827):
#0  0x0000000000000000 in ?? ()
Backtrace stopped: Cannot access memory at address 0x0

Thread 34 (Thread 0x14ac4dc20700 (LWP 3958879)):
#0  __lll_lock_wait (futex=futex@entry=0x5563bb708440 <buf_pool>, private=0) at lowlevellock.c:52
#1  0x000014ac55ab60a3 in __GI___pthread_mutex_lock (mutex=mutex@entry=0x5563bb708440 <buf_pool>) at ../nptl/pthread_mutex_lock.c:80
#2  0x00005563bad0a73d in inline_mysql_mutex_lock (that=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/include/mysql/psi/mysql_thread.h:752
#3  buf_page_write_complete (request=...) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/buf/buf0flu.cc:405
#4  0x00005563bad428f0 in fil_aio_callback (request=...) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/fil/fil0fil.cc:2874
#5  0x00005563bac2f136 in io_callback (cb=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/os/os0file.cc:3556
#6  0x00005563bad9d019 in tpool::task_group::execute (this=0x5563bcb6b590, t=0x14ac4ce0ac90) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/task_group.cc:55
#7  0x00005563bad9bda7 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb343e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:588
#8  0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#9  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#10 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 33 (Thread 0x14ac4ec28700 (LWP 3958871)):
#0  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:78
#1  0x000014ac55ab3530 in ?? () at allocatestack.c:311 from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x000014ac4ec28700 in ?? ()
#3  0x0000000000000000 in ?? ()

Thread 32 (Thread 0x14ac54637700 (LWP 3958833)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac54636d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb3598c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac54636d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35960) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35960, mutex=0x5563bcb26850, abstime=0x14ac54636d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac54636d40, __mutex=<optimized out>, __cond=0x5563bcb35960) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35960) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35960) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35960) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35960) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35960, t=0x14ac54636de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35960) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 31 (Thread 0x14ac5534a700 (LWP 3957476)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac55349d70, clockid=<optimized out>, expected=0, futex_word=0x5563bcbc6428) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac55349d70, clockid=<optimized out>, mutex=0x5563bcbc63d0, cond=0x5563bcbc6400) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcbc6400, mutex=mutex@entry=0x5563bcbc63d0, abstime=0x14ac55349d70) at pthread_cond_wait.c:665
#3  0x00005563baabae32 in inline_mysql_cond_timedwait (abstime=<optimized out>, mutex=0x5563bcbc63d0, that=0x5563bcbc6400) at /test/preview-10.10-MDEV-16329-online-alter_opt/include/mysql/psi/mysql_thread.h:1088
#4  Event_queue::cond_wait (this=this@entry=0x5563bcbc63d0, thd=thd@entry=0x14abd05f4fd8, abstime=abstime@entry=0x14ac55349d70, stage=<optimized out>, src_func=src_func@entry=0x5563bb0fd3a7 "get_top_for_execution_if_time", src_file=src_file@entry=0x5563bb0fd500 "/test/preview-10.10-MDEV-16329-online-alter_opt/sql/event_queue.cc", src_line=640) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/event_queue.cc:789
#5  0x00005563baabb1d1 in Event_queue::get_top_for_execution_if_time (this=0x5563bcbc63d0, thd=thd@entry=0x14abd05f4fd8, event_name=event_name@entry=0x14ac55349dc8) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/event_queue.cc:640
#6  0x00005563baab9f7f in Event_scheduler::run (this=this@entry=0x5563bce25e40, thd=0x14abd05f4fd8) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/event_scheduler.cc:492
#7  0x00005563baaba09c in event_scheduler_thread (arg=0x14abd006e718) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/event_scheduler.cc:236
#8  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#9  0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 30 (Thread 0x14ac552d3700 (LWP 3957606)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac552d2d60, clockid=<optimized out>, expected=0, futex_word=0x14abd052f57c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac552d2d60, clockid=<optimized out>, mutex=0x14abd052f520, cond=0x14abd052f550) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=cond@entry=0x14abd052f550, mutex=mutex@entry=0x14abd052f520, abstime=abstime@entry=0x14ac552d2d60) at pthread_cond_wait.c:665
#3  0x00005563ba6d80a8 in inline_mysql_cond_timedwait (abstime=0x14ac552d2d60, mutex=0x14abd052f520, that=0x14abd052f550) at /test/preview-10.10-MDEV-16329-online-alter_opt/include/mysql/psi/mysql_thread.h:1088
#4  handle_delayed_insert (arg=0x14abd0528d68) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/sql_insert.cc:3272
#5  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 29 (Thread 0x14ac30d53700 (LWP 3928967)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac30d52d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35d08) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac30d52d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35ce0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35ce0, mutex=0x5563bcb26850, abstime=0x14ac30d52d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac30d52d40, __mutex=<optimized out>, __cond=0x5563bcb35ce0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35ce0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35ce0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35ce0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35ce0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35ce0, t=0x14ac30d52de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35ce0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 28 (Thread 0x14ac31155700 (LWP 3928965)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac31154d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35e0c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac31154d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35de0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35de0, mutex=0x5563bcb26850, abstime=0x14ac31154d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac31154d40, __mutex=<optimized out>, __cond=0x5563bcb35de0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35de0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35de0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35de0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35de0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35de0, t=0x14ac31154de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35de0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 27 (Thread 0x14ac52721700 (LWP 3958839)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac52720d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35688) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac52720d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35660) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35660, mutex=0x5563bcb26850, abstime=0x14ac52720d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac52720d40, __mutex=<optimized out>, __cond=0x5563bcb35660) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35660) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35660) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35660) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35660) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35660, t=0x14ac52720de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35660) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 26 (Thread 0x14ac553c9800 (LWP 3928620)):
#0  0x000014ac5569299f in __GI___poll (fds=0x5563bcda4828, nfds=3, timeout=timeout@entry=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00005563ba60c4f2 in poll (__timeout=-1, __nfds=<optimized out>, __fds=<optimized out>) at /usr/include/x86_64-linux-gnu/bits/poll2.h:46
#2  handle_connections_sockets () at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/mysqld.cc:6205
#3  0x00005563ba60edec in mysqld_main (argc=<optimized out>, argv=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/mysqld.cc:5910
#4  0x000014ac555a4083 in __libc_start_main (main=0x5563ba5c35f0 <main(int, char**)>, argc=54, argv=0x7ffca5d7de78, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffca5d7de68) at ../csu/libc-start.c:308
#5  0x00005563ba6056ae in _start () at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/mysqld.cc:4557

Thread 25 (Thread 0x14ac51d1c700 (LWP 3958845)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac51d1bd40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35408) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac51d1bd40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb353e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb353e0, mutex=0x5563bcb26850, abstime=0x14ac51d1bd40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac51d1bd40, __mutex=<optimized out>, __cond=0x5563bcb353e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb353e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb353e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb353e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb353e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb353e0, t=0x14ac51d1bde8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb353e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 24 (Thread 0x14ac4e223700 (LWP 3958876)):
#0  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:78
#1  0x000014ac55ab3530 in ?? () at allocatestack.c:311 from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x000014ac4e223700 in ?? ()
#3  0x0000000000000000 in ?? ()

Thread 23 (Thread 0x14ac50e39700 (LWP 3958852)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac50e38d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35088) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac50e38d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35060) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35060, mutex=0x5563bcb26850, abstime=0x14ac50e38d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac50e38d40, __mutex=<optimized out>, __cond=0x5563bcb35060) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35060) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35060) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35060) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35060) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35060, t=0x14ac50e38de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35060) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 22 (LWP 3958823):
#0  0x0000000000000000 in ?? ()
Backtrace stopped: Cannot access memory at address 0x0

Thread 21 (Thread 0x14ac32610700 (LWP 3928899)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac3260fd40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb3620c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac3260fd40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb361e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb361e0, mutex=0x5563bcb26850, abstime=0x14ac3260fd40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac3260fd40, __mutex=<optimized out>, __cond=0x5563bcb361e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb361e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb361e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb361e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb361e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb361e0, t=0x14ac3260fde8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb361e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 20 (Thread 0x14ac52f25700 (LWP 3958835)):
#0  __lll_lock_wait (futex=futex@entry=0x5563bcb26850, private=0) at lowlevellock.c:52
#1  0x000014ac55ab807b in __pthread_mutex_cond_lock (mutex=mutex@entry=0x5563bcb26850) at ../nptl/pthread_mutex_lock.c:80
#2  0x000014ac55aba699 in __pthread_cond_wait_common (abstime=0x14ac52f24d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35860) at pthread_cond_wait.c:636
#3  __pthread_cond_timedwait (cond=0x5563bcb35860, mutex=0x5563bcb26850, abstime=0x14ac52f24d40) at pthread_cond_wait.c:665
#4  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac52f24d40, __mutex=<optimized out>, __cond=0x5563bcb35860) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#5  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35860) at /usr/include/c++/9/condition_variable:188
#6  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35860) at /usr/include/c++/9/condition_variable:121
#7  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35860) at /usr/include/c++/9/condition_variable:152
#8  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35860) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#9  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35860, t=0x14ac52f24de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#10 0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35860) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#11 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#12 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#13 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 19 (Thread 0x14ac3200d700 (LWP 3928902)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac3200cd40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb36088) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac3200cd40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb36060) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb36060, mutex=0x5563bcb26850, abstime=0x14ac3200cd40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac3200cd40, __mutex=<optimized out>, __cond=0x5563bcb36060) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb36060) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb36060) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb36060) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb36060) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb36060, t=0x14ac3200cde8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb36060) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 18 (Thread 0x14ac5523d700 (LWP 3949999)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x5563bb7b99c8 <ack_receiver+104>) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x5563bb7b9970 <ack_receiver+16>, cond=0x5563bb7b99a0 <ack_receiver+64>) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=cond@entry=0x5563bb7b99a0 <ack_receiver+64>, mutex=mutex@entry=0x5563bb7b9970 <ack_receiver+16>) at pthread_cond_wait.c:647
#3  0x00005563ba894a9a in inline_mysql_cond_wait (mutex=0x5563bb7b9970 <ack_receiver+16>, that=0x5563bb7b99a0 <ack_receiver+64>) at /test/preview-10.10-MDEV-16329-online-alter_opt/include/mysql/psi/mysql_thread.h:1072
#4  Ack_receiver::wait_for_slave_connection (this=0x5563bb7b9960 <ack_receiver>) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/semisync_master_ack_receiver.cc:173
#5  Ack_receiver::run (this=0x5563bb7b9960 <ack_receiver>) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/semisync_master_ack_receiver.cc:229
#6  0x00005563ba894aee in ack_receive_handler (arg=0x5563bb7b9960 <ack_receiver>) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/semisync_master_ack_receiver.cc:35
#7  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#8  0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 17 (Thread 0x14ac30951700 (LWP 3928969)):
#0  0x000014ac555c41a2 in __GI___sigtimedwait (set=set@entry=0x14ac30950ce0, info=info@entry=0x14ac30950d60, timeout=timeout@entry=0x0) at ../sysdeps/unix/sysv/linux/sigtimedwait.c:29
#1  0x000014ac555c420b in __GI___sigwaitinfo (set=set@entry=0x14ac30950ce0, info=info@entry=0x14ac30950d60) at ../sysdeps/unix/sysv/linux/sigwaitinfo.c:25
#2  0x00005563ba605f4a in my_sigwait (code=<synthetic pointer>, sig=0x14ac30950cdc, set=0x14ac30950ce0) at /test/preview-10.10-MDEV-16329-online-alter_opt/include/my_pthread.h:195
#3  signal_hand (arg=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/mysqld.cc:3187
#4  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#5  0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 16 (Thread 0x14ac333d5700 (LWP 3928882)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac333d4d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb36408) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac333d4d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb363e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb363e0, mutex=0x5563bcb26850, abstime=0x14ac333d4d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac333d4d40, __mutex=<optimized out>, __cond=0x5563bcb363e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb363e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb363e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb363e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb363e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb363e0, t=0x14ac333d4de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb363e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 15 (Thread 0x14ac4e022700 (LWP 3958877)):
#0  __lll_lock_wait (futex=futex@entry=0x5563bcb26850, private=0) at lowlevellock.c:52
#1  0x000014ac55ab60a3 in __GI___pthread_mutex_lock (mutex=0x5563bcb26850) at ../nptl/pthread_mutex_lock.c:80
#2  0x00005563bad9a6fe in __gthread_mutex_lock (__mutex=0x5563bcb26850) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:749
#3  std::mutex::lock (this=0x5563bcb26850) at /usr/include/c++/9/bits/std_mutex.h:100
#4  std::unique_lock<std::mutex>::lock (this=0x14ac4e021d90, this=0x14ac4e021d90) at /usr/include/c++/9/bits/unique_lock.h:141
#5  std::unique_lock<std::mutex>::unique_lock (__m=..., this=0x14ac4e021d90) at /usr/include/c++/9/bits/unique_lock.h:71
#6  tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb344e0, t=0x14ac4e021de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:526
#7  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb344e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#8  0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#9  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#10 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 14 (Thread 0x14ac4e826700 (LWP 3958873)):
#0  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:78
#1  0x000014ac55ab3530 in ?? () at allocatestack.c:311 from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x000014ac4e826700 in ?? ()
#3  0x0000000000000000 in ?? ()

Thread 13 (Thread 0x14ac54838700 (LWP 3958832)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac54837d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35a08) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac54837d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb359e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb359e0, mutex=0x5563bcb26850, abstime=0x14ac54837d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac54837d40, __mutex=<optimized out>, __cond=0x5563bcb359e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb359e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb359e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb359e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb359e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb359e0, t=0x14ac54837de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb359e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 12 (Thread 0x14ac54a39700 (LWP 3958831)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac54a38d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35a88) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac54a38d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35a60) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35a60, mutex=0x5563bcb26850, abstime=0x14ac54a38d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac54a38d40, __mutex=<optimized out>, __cond=0x5563bcb35a60) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35a60) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35a60) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35a60) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35a60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35a60, t=0x14ac54a38de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35a60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 11 (Thread 0x14ac317a3700 (LWP 3928925)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x5563bb7bda60 <mysql_bin_log+3264>) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x5563bb7bda08 <mysql_bin_log+3176>, cond=0x5563bb7bda38 <mysql_bin_log+3224>) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=cond@entry=0x5563bb7bda38 <mysql_bin_log+3224>, mutex=mutex@entry=0x5563bb7bda08 <mysql_bin_log+3176>) at pthread_cond_wait.c:647
#3  0x00005563baa6514a in inline_mysql_cond_wait (mutex=0x5563bb7bda08 <mysql_bin_log+3176>, that=0x5563bb7bda38 <mysql_bin_log+3224>) at /test/preview-10.10-MDEV-16329-online-alter_opt/include/mysql/psi/mysql_thread.h:1072
#4  binlog_background_thread (arg=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/log.cc:10952
#5  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 10 (Thread 0x14ac32a12700 (LWP 3928897)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac32a11d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb3630c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac32a11d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb362e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb362e0, mutex=0x5563bcb26850, abstime=0x14ac32a11d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac32a11d40, __mutex=<optimized out>, __cond=0x5563bcb362e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb362e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb362e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb362e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb362e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb362e0, t=0x14ac32a11de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb362e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 9 (Thread 0x14ac3220e700 (LWP 3928901)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac3220dd40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb36108) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac3220dd40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb360e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb360e0, mutex=0x5563bcb26850, abstime=0x14ac3220dd40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac3220dd40, __mutex=<optimized out>, __cond=0x5563bcb360e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb360e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb360e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb360e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb360e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb360e0, t=0x14ac3220dde8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb360e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 8 (Thread 0x14ac33bab700 (LWP 3928798)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x5563bb70c7e0 <buf_pool+17312>) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x5563bb70c740 <buf_pool+17152>, cond=0x5563bb70c7b8 <buf_pool+17272>) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=cond@entry=0x5563bb70c7b8 <buf_pool+17272>, mutex=mutex@entry=0x5563bb70c740 <buf_pool+17152>) at pthread_cond_wait.c:647
#3  0x00005563bad0c830 in buf_flush_page_cleaner () at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/buf/buf0flu.cc:2398
#4  0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#5  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 7 (Thread 0x14ac31758700 (LWP 3928962)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac31757d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35f8c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac31757d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35f60) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35f60, mutex=0x5563bcb26850, abstime=0x14ac31757d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac31757d40, __mutex=<optimized out>, __cond=0x5563bcb35f60) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35f60) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35f60) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35f60) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35f60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35f60, t=0x14ac31757de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35f60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 6 (Thread 0x14ac31356700 (LWP 3928964)):
#0  __lll_lock_wait (futex=futex@entry=0x5563bb708440 <buf_pool>, private=0) at lowlevellock.c:52
#1  0x000014ac55ab60a3 in __GI___pthread_mutex_lock (mutex=mutex@entry=0x5563bb708440 <buf_pool>) at ../nptl/pthread_mutex_lock.c:80
#2  0x00005563bad0a73d in inline_mysql_mutex_lock (that=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/include/mysql/psi/mysql_thread.h:752
#3  buf_page_write_complete (request=...) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/buf/buf0flu.cc:405
#4  0x00005563bad428f0 in fil_aio_callback (request=...) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/fil/fil0fil.cc:2874
#5  0x00005563bac2f136 in io_callback (cb=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/os/os0file.cc:3556
#6  0x00005563bad9d019 in tpool::task_group::execute (this=0x5563bcb6b590, t=0x14ac4ce0b4e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/task_group.cc:55
#7  0x00005563bad9bda7 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35e60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:588
#8  0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#9  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#10 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 5 (Thread 0x14ac4c078700 (LWP 3928923)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x5563bb79252c <COND_manager+44>) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x5563bb792540 <LOCK_manager>, cond=0x5563bb792500 <COND_manager>) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=cond@entry=0x5563bb792500 <COND_manager>, mutex=mutex@entry=0x5563bb792540 <LOCK_manager>) at pthread_cond_wait.c:647
#3  0x00005563ba6fd95b in inline_mysql_cond_wait (mutex=0x5563bb792540 <LOCK_manager>, that=0x5563bb792500 <COND_manager>) at /test/preview-10.10-MDEV-16329-online-alter_opt/include/mysql/psi/mysql_thread.h:1072
#4  handle_manager (arg=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/sql_manager.cc:103
#5  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 4 (Thread 0x14ac4cdba700 (LWP 3928779)):
#0  futex_wake (private=<optimized out>, processes_to_wake=1, futex_word=<optimized out>) at ../sysdeps/nptl/futex-internal.h:364
#1  __pthread_cond_signal (cond=0x5563bcb35860) at pthread_cond_signal.c:94
#2  0x000014ac55993e4d in std::condition_variable::notify_one() () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#3  0x00005563bad9a8ef in tpool::thread_pool_generic::wake (reason=<optimized out>, this=0x5563bcb26740) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:787
#4  tpool::thread_pool_generic::wake (this=0x5563bcb26740, reason=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:776
#5  0x00005563bad9be98 in tpool::thread_pool_generic::submit_task (this=0x5563bcb26740, task=0x14ac4ce04838) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:864
#6  0x00005563bad9dd15 in (anonymous namespace)::aio_uring::thread_routine (aio=0x5563bcb6d690) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/aio_liburing.cc:175
#7  0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#8  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#9  0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 3 (Thread 0x14ac319a4700 (LWP 3928921)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac319a3d90, clockid=<optimized out>, expected=0, futex_word=0x5563bbfbfa48 <COND_checkpoint+40>) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac319a3d90, clockid=<optimized out>, mutex=0x5563bbfbfa60 <LOCK_checkpoint>, cond=0x5563bbfbfa20 <COND_checkpoint>) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bbfbfa20 <COND_checkpoint>, mutex=0x5563bbfbfa60 <LOCK_checkpoint>, abstime=abstime@entry=0x14ac319a3d90) at pthread_cond_wait.c:665
#3  0x00005563bab23e8d in inline_mysql_cond_timedwait (abstime=0x14ac319a3d90, mutex=<optimized out>, that=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/include/mysql/psi/mysql_thread.h:1088
#4  my_service_thread_sleep (control=control@entry=0x5563bb6f72c0 <checkpoint_control>, sleep_time=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/maria/ma_servicethread.c:115
#5  0x00005563bab1c585 in ma_checkpoint_background (arg=0x1e) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/maria/ma_checkpoint.c:725
#6  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#7  0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 2 (Thread 0x14ac5524e700 (LWP 3928716)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac5524ddf0, clockid=<optimized out>, expected=0, futex_word=0x5563bc01058c <COND_timer+44>) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac5524ddf0, clockid=<optimized out>, mutex=0x5563bc0105a0 <LOCK_timer>, cond=0x5563bc010560 <COND_timer>) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=cond@entry=0x5563bc010560 <COND_timer>, mutex=mutex@entry=0x5563bc0105a0 <LOCK_timer>, abstime=abstime@entry=0x14ac5524ddf0) at pthread_cond_wait.c:665
#3  0x00005563bae014d9 in inline_mysql_cond_timedwait (abstime=0x14ac5524ddf0, mutex=0x5563bc0105a0 <LOCK_timer>, that=0x5563bc010560 <COND_timer>) at /test/preview-10.10-MDEV-16329-online-alter_opt/include/mysql/psi/mysql_thread.h:1088
#4  timer_handler (arg=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/mysys/thr_timer.c:321
#5  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 1 (Thread 0x14ac32811700 (LWP 3928898)):
#0  buf_flush_LRU_list_batch (n=<synthetic pointer>, n=<synthetic pointer>, max=1536) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/buf/buf0flu.cc:1280
#1  buf_do_LRU_batch (max=1536) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/buf/buf0flu.cc:1374
#2  buf_flush_LRU (max_n=1536) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/buf/buf0flu.cc:1715
#3  0x00005563ba5a8f23 in buf_pool_t::withdraw_blocks (this=this@entry=0x5563bb708440 <buf_pool>) at /usr/include/c++/9/bits/stl_algobase.h:222
#4  0x00005563bad0512d in buf_pool_t::resize (this=this@entry=0x5563bb708440 <buf_pool>) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/include/buf0buf.h:1546
#5  0x00005563bad0321c in buf_resize_callback () at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/buf/buf0buf.cc:1972
#6  0x00005563bad9d019 in tpool::task_group::execute (this=0x5563bc006c20 <single_threaded_group>, t=0x5563bc006b80 <buf_resize_task>) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/task_group.cc:55
#7  0x00005563bad9bda7 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb36260) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:588
#8  0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#9  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#10 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 79 (Thread 0x14ac4f22b700 (LWP 3958867)):
#0  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:78
#1  0x000014ac55ab3530 in ?? () at allocatestack.c:311 from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x000014ac4f22b700 in ?? ()
#3  0x0000000000000000 in ?? ()

Thread 78 (Thread 0x14ac4f02a700 (LWP 3958868)):
#0  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:78
#1  0x000014ac55ab3530 in ?? () at allocatestack.c:311 from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x000014ac4f02a700 in ?? ()
#3  0x0000000000000000 in ?? ()

Thread 77 (Thread 0x14ac4e424700 (LWP 3958875)):
#0  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:78
#1  0x000014ac55ab3530 in ?? () at allocatestack.c:311 from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x000014ac4e424700 in ?? ()
#3  0x0000000000000000 in ?? ()

Thread 76 (Thread 0x14ac4de21700 (LWP 3958878)):
#0  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:78
#1  0x000014ac55ab3530 in ?? () at allocatestack.c:311 from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x000014ac4de21700 in ?? ()
#3  0x0000000000000000 in ?? ()

Thread 75 (Thread 0x14ac5231f700 (LWP 3958841)):
#0  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:78
#1  0x000014ac55ab3530 in ?? () at allocatestack.c:311 from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x000014ac5231f700 in ?? ()
#3  0x0000000000000000 in ?? ()

Thread 74 (Thread 0x14ac54e3b700 (LWP 3958829)):
#0  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:78
#1  0x000014ac55ab3530 in ?? () at allocatestack.c:311 from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x000014ac54e3b700 in ?? ()
#3  0x0000000000000000 in ?? ()

Thread 73 (Thread 0x14ac4ee29700 (LWP 3958870)):
#0  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:78
#1  0x000014ac55ab3530 in ?? () at allocatestack.c:311 from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x000014ac4ee29700 in ?? ()
#3  0x0000000000000000 in ?? ()

Thread 72 (Thread 0x14ac51f1d700 (LWP 3958844)):
#0  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:78
#1  0x000014ac55ab3530 in ?? () at allocatestack.c:311 from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x000014ac51f1d700 in ?? ()
#3  0x0000000000000000 in ?? ()

Thread 71 (Thread 0x14ac50032700 (LWP 3958859)):
#0  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:78
#1  0x000014ac55ab3530 in ?? () at allocatestack.c:311 from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x000014ac50032700 in ?? ()
#3  0x0000000000000000 in ?? ()

Thread 70 (Thread 0x14ac4ea27700 (LWP 3958872)):
#0  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:78
#1  0x000014ac55ab3530 in ?? () at allocatestack.c:311 from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x000014ac4ea27700 in ?? ()
#3  0x0000000000000000 in ?? ()

Thread 69 (Thread 0x14ac4f42c700 (LWP 3958866)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac4f42bd40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb34a0c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac4f42bd40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb349e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb349e0, mutex=0x5563bcb26850, abstime=0x14ac4f42bd40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac4f42bd40, __mutex=<optimized out>, __cond=0x5563bcb349e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb349e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb349e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb349e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb349e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb349e0, t=0x14ac4f42bde8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb349e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 68 (Thread 0x14ac52b23700 (LWP 3958837)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac52b22d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35788) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac52b22d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35760) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35760, mutex=0x5563bcb26850, abstime=0x14ac52b22d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac52b22d40, __mutex=<optimized out>, __cond=0x5563bcb35760) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35760) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35760) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35760) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35760) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35760, t=0x14ac52b22de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35760) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 67 (Thread 0x14ac331d4700 (LWP 3928883)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac331d3d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb3638c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac331d3d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb36360) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb36360, mutex=0x5563bcb26850, abstime=0x14ac331d3d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac331d3d40, __mutex=<optimized out>, __cond=0x5563bcb36360) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb36360) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb36360) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb36360) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb36360) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb36360, t=0x14ac331d3de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb36360) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 66 (Thread 0x14ac50434700 (LWP 3958857)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac50433d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb34e08) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac50433d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb34de0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb34de0, mutex=0x5563bcb26850, abstime=0x14ac50433d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac50433d40, __mutex=<optimized out>, __cond=0x5563bcb34de0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb34de0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb34de0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb34de0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb34de0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb34de0, t=0x14ac50433de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb34de0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 65 (Thread 0x14ac52520700 (LWP 3958840)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac5251fd40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35608) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac5251fd40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb355e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb355e0, mutex=0x5563bcb26850, abstime=0x14ac5251fd40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac5251fd40, __mutex=<optimized out>, __cond=0x5563bcb355e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb355e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb355e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb355e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb355e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb355e0, t=0x14ac5251fde8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb355e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 64 (Thread 0x14ac5503c700 (LWP 3958828)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac5503bd40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35c08) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac5503bd40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35be0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35be0, mutex=0x5563bcb26850, abstime=0x14ac5503bd40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac5503bd40, __mutex=<optimized out>, __cond=0x5563bcb35be0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35be0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35be0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35be0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35be0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35be0, t=0x14ac5503bde8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35be0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 63 (Thread 0x14ac30b52700 (LWP 3928968)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac30b51d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35c8c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac30b51d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35c60) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35c60, mutex=0x5563bcb26850, abstime=0x14ac30b51d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac30b51d40, __mutex=<optimized out>, __cond=0x5563bcb35c60) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35c60) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35c60) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35c60) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35c60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35c60, t=0x14ac30b51de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35c60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 62 (Thread 0x14ac4f62d700 (LWP 3958865)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac4f62cd40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb34a88) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac4f62cd40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb34a60) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb34a60, mutex=0x5563bcb26850, abstime=0x14ac4f62cd40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac4f62cd40, __mutex=<optimized out>, __cond=0x5563bcb34a60) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb34a60) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb34a60) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb34a60) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb34a60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb34a60, t=0x14ac4f62cde8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb34a60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 61 (Thread 0x14ac4fa2f700 (LWP 3958863)):
#0  __lll_lock_wait (futex=futex@entry=0x5563bb708440 <buf_pool>, private=0) at lowlevellock.c:52
#1  0x000014ac55ab60a3 in __GI___pthread_mutex_lock (mutex=mutex@entry=0x5563bb708440 <buf_pool>) at ../nptl/pthread_mutex_lock.c:80
#2  0x00005563bad0a73d in inline_mysql_mutex_lock (that=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/include/mysql/psi/mysql_thread.h:752
#3  buf_page_write_complete (request=...) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/buf/buf0flu.cc:405
#4  0x00005563bad428f0 in fil_aio_callback (request=...) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/fil/fil0fil.cc:2874
#5  0x00005563bac2f136 in io_callback (cb=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/os/os0file.cc:3556
#6  0x00005563bad9d019 in tpool::task_group::execute (this=0x5563bcb6b590, t=0x14ac4ce06b40) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/task_group.cc:55
#7  0x00005563bad9bda7 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb34b60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:588
#8  0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#9  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#10 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 60 (Thread 0x14ac30906700 (LWP 3931858)):
#0  __libc_send (flags=<optimized out>, len=62, buf=0x14abd05a8318, fd=43) at ../sysdeps/unix/sysv/linux/send.c:28
#1  __libc_send (fd=43, buf=buf@entry=0x14abd05a8318, len=len@entry=62, flags=flags@entry=64) at ../sysdeps/unix/sysv/linux/send.c:23
#2  0x00005563baac96be in inline_mysql_socket_send (flags=64, n=62, buf=0x14abd05a8318, mysql_socket=...) at /test/preview-10.10-MDEV-16329-online-alter_opt/include/mysql/psi/mysql_socket.h:849
#3  vio_write (vio=0x14abd0008288, buf=0x14abd05a8318 ":", size=62) at /test/preview-10.10-MDEV-16329-online-alter_opt/vio/viosocket.c:267
#4  0x00005563baa944c6 in net_real_write (net=net@entry=0x14abd0000f08, packet=0x14abd05a8318 ":", len=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/net_serv.cc:722
#5  0x00005563baa94787 in net_flush (net=net@entry=0x14abd0000f08) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/net_serv.cc:402
#6  0x00005563baa94ef1 in net_write_command (net=net@entry=0x14abd0000f08, command=command@entry=255 '\377', header=header@entry=0x5563bb0fc224 "", head_len=<optimized out>, head_len@entry=0, packet=0x14ac30905110 "p\004#21S01Broj kolona ne odgovara broju vrednosti u slogu 1", len=57) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/net_serv.cc:550
#7  0x00005563ba63cac0 in Protocol::net_send_error_packet (this=<optimized out>, thd=0x14abd0000c58, sql_errno=1136, err=<optimized out>, sqlstate=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/protocol.cc:475
#8  0x00005563ba63dc1b in Protocol::send_error (sql_state=<optimized out>, err_msg=<optimized out>, sql_errno=<optimized out>, this=0x14abd00011d8) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/protocol.cc:671
#9  Protocol::end_statement (this=0x14abd00011d8) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/protocol.cc:596
#10 0x00005563ba70a1ad in dispatch_command (command=COM_QUERY, thd=0x14abd0000c58, packet=<optimized out>, packet_length=<optimized out>, blocking=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/sql_parse.cc:2401
#11 0x00005563ba70cd82 in do_command (thd=0x14abd0000c58, blocking=blocking@entry=true) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/sql_parse.cc:1407
#12 0x00005563ba823e7f in do_handle_one_connection (connect=<optimized out>, connect@entry=0x5563bce20798, put_in_cache=put_in_cache@entry=true) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/sql_connect.cc:1418
#13 0x00005563ba82415d in handle_one_connection (arg=0x5563bce20798) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/sql_connect.cc:1312
#14 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#15 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 59 (Thread 0x14ac31557700 (LWP 3928963)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac31556d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35f0c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac31556d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35ee0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35ee0, mutex=0x5563bcb26850, abstime=0x14ac31556d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac31556d40, __mutex=<optimized out>, __cond=0x5563bcb35ee0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35ee0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35ee0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35ee0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35ee0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35ee0, t=0x14ac31556de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35ee0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 58 (Thread 0x14ac5103a700 (LWP 3958851)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac51039d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35108) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac51039d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb350e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb350e0, mutex=0x5563bcb26850, abstime=0x14ac51039d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac51039d40, __mutex=<optimized out>, __cond=0x5563bcb350e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb350e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb350e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb350e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb350e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb350e0, t=0x14ac51039de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb350e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 57 (Thread 0x14ac50a37700 (LWP 3958854)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac50a36d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb34f8c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac50a36d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb34f60) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb34f60, mutex=0x5563bcb26850, abstime=0x14ac50a36d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac50a36d40, __mutex=<optimized out>, __cond=0x5563bcb34f60) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb34f60) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb34f60) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb34f60) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb34f60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb34f60, t=0x14ac50a36de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb34f60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 56 (Thread 0x14ac4fc30700 (LWP 3958861)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac4fc2fd40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb34c0c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac4fc2fd40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb34be0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb34be0, mutex=0x5563bcb26850, abstime=0x14ac4fc2fd40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac4fc2fd40, __mutex=<optimized out>, __cond=0x5563bcb34be0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb34be0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb34be0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb34be0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb34be0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb34be0, t=0x14ac4fc2fde8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb34be0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 55 (Thread 0x14ac4f82e700 (LWP 3958864)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac4f82dd40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb34b08) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac4f82dd40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb34ae0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb34ae0, mutex=0x5563bcb26850, abstime=0x14ac4f82dd40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac4f82dd40, __mutex=<optimized out>, __cond=0x5563bcb34ae0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb34ae0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb34ae0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb34ae0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb34ae0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb34ae0, t=0x14ac4f82dde8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb34ae0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 54 (Thread 0x14ac31e0c700 (LWP 3928903)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac31e0bd40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb36008) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac31e0bd40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35fe0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35fe0, mutex=0x5563bcb26850, abstime=0x14ac31e0bd40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac31e0bd40, __mutex=<optimized out>, __cond=0x5563bcb35fe0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35fe0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35fe0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35fe0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35fe0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35fe0, t=0x14ac31e0bde8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35fe0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 53 (Thread 0x14ac52922700 (LWP 3958838)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac52921d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb3570c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac52921d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb356e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb356e0, mutex=0x5563bcb26850, abstime=0x14ac52921d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac52921d40, __mutex=<optimized out>, __cond=0x5563bcb356e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb356e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb356e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb356e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb356e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb356e0, t=0x14ac52921de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb356e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 52 (Thread 0x14ac5123b700 (LWP 3958850)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac5123ad40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35188) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac5123ad40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35160) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35160, mutex=0x5563bcb26850, abstime=0x14ac5123ad40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac5123ad40, __mutex=<optimized out>, __cond=0x5563bcb35160) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35160) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35160) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35160) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35160) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35160, t=0x14ac5123ade8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35160) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 51 (Thread 0x14ac30f54700 (LWP 3928966)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac30f53d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35d88) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac30f53d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35d60) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35d60, mutex=0x5563bcb26850, abstime=0x14ac30f53d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac30f53d40, __mutex=<optimized out>, __cond=0x5563bcb35d60) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35d60) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35d60) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35d60) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35d60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35d60, t=0x14ac30f53de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35d60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 50 (Thread 0x14ac50c38700 (LWP 3958853)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac50c37d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35008) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac50c37d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb34fe0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb34fe0, mutex=0x5563bcb26850, abstime=0x14ac50c37d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac50c37d40, __mutex=<optimized out>, __cond=0x5563bcb34fe0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb34fe0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb34fe0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb34fe0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb34fe0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb34fe0, t=0x14ac50c37de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb34fe0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 49 (Thread 0x14ac51518700 (LWP 3958849)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac51517d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35208) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac51517d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb351e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb351e0, mutex=0x5563bcb26850, abstime=0x14ac51517d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac51517d40, __mutex=<optimized out>, __cond=0x5563bcb351e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb351e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb351e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb351e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb351e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb351e0, t=0x14ac51517de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb351e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 48 (Thread 0x14ac4e625700 (LWP 3958874)):
#0  __lll_lock_wait (futex=futex@entry=0x5563bcb26850, private=0) at lowlevellock.c:52
#1  0x000014ac55ab807b in __pthread_mutex_cond_lock (mutex=mutex@entry=0x5563bcb26850) at ../nptl/pthread_mutex_lock.c:80
#2  0x000014ac55aba699 in __pthread_cond_wait_common (abstime=0x14ac4e624d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb34660) at pthread_cond_wait.c:636
#3  __pthread_cond_timedwait (cond=0x5563bcb34660, mutex=0x5563bcb26850, abstime=0x14ac4e624d40) at pthread_cond_wait.c:665
#4  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac4e624d40, __mutex=<optimized out>, __cond=0x5563bcb34660) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#5  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb34660) at /usr/include/c++/9/condition_variable:188
#6  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb34660) at /usr/include/c++/9/condition_variable:121
#7  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb34660) at /usr/include/c++/9/condition_variable:152
#8  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb34660) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#9  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb34660, t=0x14ac4e624de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#10 0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb34660) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#11 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#12 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#13 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 47 (Thread 0x14ac54c3a700 (LWP 3958830)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac54c39d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35b08) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac54c39d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35ae0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35ae0, mutex=0x5563bcb26850, abstime=0x14ac54c39d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac54c39d40, __mutex=<optimized out>, __cond=0x5563bcb35ae0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35ae0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35ae0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35ae0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35ae0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35ae0, t=0x14ac54c39de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35ae0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 46 (Thread 0x14ac51719700 (LWP 3958848)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac51718d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35288) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac51718d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35260) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35260, mutex=0x5563bcb26850, abstime=0x14ac51718d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac51718d40, __mutex=<optimized out>, __cond=0x5563bcb35260) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35260) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35260) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35260) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35260) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35260, t=0x14ac51718de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35260) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 45 (Thread 0x14ac50836700 (LWP 3958855)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac50835d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb34f0c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac50835d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb34ee0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb34ee0, mutex=0x5563bcb26850, abstime=0x14ac50835d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac50835d40, __mutex=<optimized out>, __cond=0x5563bcb34ee0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb34ee0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb34ee0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb34ee0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb34ee0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb34ee0, t=0x14ac50835de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb34ee0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 44 (Thread 0x14ac3240f700 (LWP 3928900)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac3240ed40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb3618c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac3240ed40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb36160) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb36160, mutex=0x5563bcb26850, abstime=0x14ac3240ed40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac3240ed40, __mutex=<optimized out>, __cond=0x5563bcb36160) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb36160) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb36160) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb36160) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb36160) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb36160, t=0x14ac3240ede8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb36160) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 43 (Thread 0x14ac50635700 (LWP 3958856)):
#0  __lll_lock_wait (futex=futex@entry=0x5563bb708440 <buf_pool>, private=0) at lowlevellock.c:52
#1  0x000014ac55ab60a3 in __GI___pthread_mutex_lock (mutex=mutex@entry=0x5563bb708440 <buf_pool>) at ../nptl/pthread_mutex_lock.c:80
#2  0x00005563bad0a73d in inline_mysql_mutex_lock (that=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/include/mysql/psi/mysql_thread.h:752
#3  buf_page_write_complete (request=...) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/buf/buf0flu.cc:405
#4  0x00005563bad428f0 in fil_aio_callback (request=...) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/fil/fil0fil.cc:2874
#5  0x00005563bac2f136 in io_callback (cb=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/os/os0file.cc:3556
#6  0x00005563bad9d019 in tpool::task_group::execute (this=0x5563bcb6b590, t=0x14ac4ce0ad28) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/task_group.cc:55
#7  0x00005563bad9bda7 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb34e60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:588
#8  0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#9  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#10 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 42 (Thread 0x14ac4fe31700 (LWP 3958860)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac4fe30d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb34c8c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac4fe30d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb34c60) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb34c60, mutex=0x5563bcb26850, abstime=0x14ac4fe30d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac4fe30d40, __mutex=<optimized out>, __cond=0x5563bcb34c60) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb34c60) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb34c60) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb34c60) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb34c60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb34c60, t=0x14ac4fe30de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb34c60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 41 (Thread 0x14ac52d24700 (LWP 3958836)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac52d23d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb3580c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac52d23d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb357e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb357e0, mutex=0x5563bcb26850, abstime=0x14ac52d23d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac52d23d40, __mutex=<optimized out>, __cond=0x5563bcb357e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb357e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb357e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb357e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb357e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb357e0, t=0x14ac52d23de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb357e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 40 (Thread 0x14ac53126700 (LWP 3958834)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac53125d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35908) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac53125d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb358e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb358e0, mutex=0x5563bcb26850, abstime=0x14ac53125d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac53125d40, __mutex=<optimized out>, __cond=0x5563bcb358e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb358e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb358e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb358e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb358e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb358e0, t=0x14ac53125de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb358e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 39 (Thread 0x14ac5211e700 (LWP 3958843)):
#0  __lll_lock_wait (futex=futex@entry=0x5563bcb26850, private=0) at lowlevellock.c:52
#1  0x000014ac55ab807b in __pthread_mutex_cond_lock (mutex=mutex@entry=0x5563bcb26850) at ../nptl/pthread_mutex_lock.c:80
#2  0x000014ac55aba699 in __pthread_cond_wait_common (abstime=0x14ac5211dd40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb354e0) at pthread_cond_wait.c:636
#3  __pthread_cond_timedwait (cond=0x5563bcb354e0, mutex=0x5563bcb26850, abstime=0x14ac5211dd40) at pthread_cond_wait.c:665
#4  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac5211dd40, __mutex=<optimized out>, __cond=0x5563bcb354e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#5  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb354e0) at /usr/include/c++/9/condition_variable:188
#6  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb354e0) at /usr/include/c++/9/condition_variable:121
#7  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb354e0) at /usr/include/c++/9/condition_variable:152
#8  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb354e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#9  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb354e0, t=0x14ac5211dde8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#10 0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb354e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#11 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#12 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#13 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 38 (Thread 0x14ac5191a700 (LWP 3958847)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac51919d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35308) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac51919d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb352e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb352e0, mutex=0x5563bcb26850, abstime=0x14ac51919d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac51919d40, __mutex=<optimized out>, __cond=0x5563bcb352e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb352e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb352e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb352e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb352e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb352e0, t=0x14ac51919de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb352e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 37 (Thread 0x14ac50233700 (LWP 3958858)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac50232d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb34d8c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac50232d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb34d60) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb34d60, mutex=0x5563bcb26850, abstime=0x14ac50232d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac50232d40, __mutex=<optimized out>, __cond=0x5563bcb34d60) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb34d60) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb34d60) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb34d60) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb34d60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb34d60, t=0x14ac50232de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb34d60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 36 (Thread 0x14ac51b1b700 (LWP 3958846)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac51b1ad40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35388) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac51b1ad40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35360) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35360, mutex=0x5563bcb26850, abstime=0x14ac51b1ad40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac51b1ad40, __mutex=<optimized out>, __cond=0x5563bcb35360) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35360) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35360) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35360) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35360) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35360, t=0x14ac51b1ade8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35360) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 35 (LWP 3958827):
#0  0x0000000000000000 in ?? ()
Backtrace stopped: Cannot access memory at address 0x0

Thread 34 (Thread 0x14ac4dc20700 (LWP 3958879)):
#0  __lll_lock_wait (futex=futex@entry=0x5563bb708440 <buf_pool>, private=0) at lowlevellock.c:52
#1  0x000014ac55ab60a3 in __GI___pthread_mutex_lock (mutex=mutex@entry=0x5563bb708440 <buf_pool>) at ../nptl/pthread_mutex_lock.c:80
#2  0x00005563bad0a73d in inline_mysql_mutex_lock (that=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/include/mysql/psi/mysql_thread.h:752
#3  buf_page_write_complete (request=...) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/buf/buf0flu.cc:405
#4  0x00005563bad428f0 in fil_aio_callback (request=...) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/fil/fil0fil.cc:2874
#5  0x00005563bac2f136 in io_callback (cb=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/os/os0file.cc:3556
#6  0x00005563bad9d019 in tpool::task_group::execute (this=0x5563bcb6b590, t=0x14ac4ce0ac90) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/task_group.cc:55
#7  0x00005563bad9bda7 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb343e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:588
#8  0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#9  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#10 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 33 (Thread 0x14ac4ec28700 (LWP 3958871)):
#0  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:78
#1  0x000014ac55ab3530 in ?? () at allocatestack.c:311 from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x000014ac4ec28700 in ?? ()
#3  0x0000000000000000 in ?? ()

Thread 32 (Thread 0x14ac54637700 (LWP 3958833)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac54636d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb3598c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac54636d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35960) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35960, mutex=0x5563bcb26850, abstime=0x14ac54636d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac54636d40, __mutex=<optimized out>, __cond=0x5563bcb35960) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35960) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35960) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35960) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35960) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35960, t=0x14ac54636de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35960) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 31 (Thread 0x14ac5534a700 (LWP 3957476)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac55349d70, clockid=<optimized out>, expected=0, futex_word=0x5563bcbc6428) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac55349d70, clockid=<optimized out>, mutex=0x5563bcbc63d0, cond=0x5563bcbc6400) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcbc6400, mutex=mutex@entry=0x5563bcbc63d0, abstime=0x14ac55349d70) at pthread_cond_wait.c:665
#3  0x00005563baabae32 in inline_mysql_cond_timedwait (abstime=<optimized out>, mutex=0x5563bcbc63d0, that=0x5563bcbc6400) at /test/preview-10.10-MDEV-16329-online-alter_opt/include/mysql/psi/mysql_thread.h:1088
#4  Event_queue::cond_wait (this=this@entry=0x5563bcbc63d0, thd=thd@entry=0x14abd05f4fd8, abstime=abstime@entry=0x14ac55349d70, stage=<optimized out>, src_func=src_func@entry=0x5563bb0fd3a7 "get_top_for_execution_if_time", src_file=src_file@entry=0x5563bb0fd500 "/test/preview-10.10-MDEV-16329-online-alter_opt/sql/event_queue.cc", src_line=640) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/event_queue.cc:789
#5  0x00005563baabb1d1 in Event_queue::get_top_for_execution_if_time (this=0x5563bcbc63d0, thd=thd@entry=0x14abd05f4fd8, event_name=event_name@entry=0x14ac55349dc8) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/event_queue.cc:640
#6  0x00005563baab9f7f in Event_scheduler::run (this=this@entry=0x5563bce25e40, thd=0x14abd05f4fd8) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/event_scheduler.cc:492
#7  0x00005563baaba09c in event_scheduler_thread (arg=0x14abd006e718) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/event_scheduler.cc:236
#8  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#9  0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 30 (Thread 0x14ac552d3700 (LWP 3957606)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac552d2d60, clockid=<optimized out>, expected=0, futex_word=0x14abd052f57c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac552d2d60, clockid=<optimized out>, mutex=0x14abd052f520, cond=0x14abd052f550) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=cond@entry=0x14abd052f550, mutex=mutex@entry=0x14abd052f520, abstime=abstime@entry=0x14ac552d2d60) at pthread_cond_wait.c:665
#3  0x00005563ba6d80a8 in inline_mysql_cond_timedwait (abstime=0x14ac552d2d60, mutex=0x14abd052f520, that=0x14abd052f550) at /test/preview-10.10-MDEV-16329-online-alter_opt/include/mysql/psi/mysql_thread.h:1088
#4  handle_delayed_insert (arg=0x14abd0528d68) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/sql_insert.cc:3272
#5  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 29 (Thread 0x14ac30d53700 (LWP 3928967)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac30d52d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35d08) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac30d52d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35ce0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35ce0, mutex=0x5563bcb26850, abstime=0x14ac30d52d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac30d52d40, __mutex=<optimized out>, __cond=0x5563bcb35ce0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35ce0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35ce0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35ce0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35ce0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35ce0, t=0x14ac30d52de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35ce0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 28 (Thread 0x14ac31155700 (LWP 3928965)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac31154d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35e0c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac31154d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35de0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35de0, mutex=0x5563bcb26850, abstime=0x14ac31154d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac31154d40, __mutex=<optimized out>, __cond=0x5563bcb35de0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35de0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35de0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35de0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35de0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35de0, t=0x14ac31154de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35de0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 27 (Thread 0x14ac52721700 (LWP 3958839)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac52720d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35688) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac52720d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35660) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35660, mutex=0x5563bcb26850, abstime=0x14ac52720d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac52720d40, __mutex=<optimized out>, __cond=0x5563bcb35660) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35660) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35660) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35660) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35660) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35660, t=0x14ac52720de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35660) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 26 (Thread 0x14ac553c9800 (LWP 3928620)):
#0  0x000014ac5569299f in __GI___poll (fds=0x5563bcda4828, nfds=3, timeout=timeout@entry=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00005563ba60c4f2 in poll (__timeout=-1, __nfds=<optimized out>, __fds=<optimized out>) at /usr/include/x86_64-linux-gnu/bits/poll2.h:46
#2  handle_connections_sockets () at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/mysqld.cc:6205
#3  0x00005563ba60edec in mysqld_main (argc=<optimized out>, argv=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/mysqld.cc:5910
#4  0x000014ac555a4083 in __libc_start_main (main=0x5563ba5c35f0 <main(int, char**)>, argc=54, argv=0x7ffca5d7de78, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffca5d7de68) at ../csu/libc-start.c:308
#5  0x00005563ba6056ae in _start () at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/mysqld.cc:4557

Thread 25 (Thread 0x14ac51d1c700 (LWP 3958845)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac51d1bd40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35408) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac51d1bd40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb353e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb353e0, mutex=0x5563bcb26850, abstime=0x14ac51d1bd40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac51d1bd40, __mutex=<optimized out>, __cond=0x5563bcb353e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb353e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb353e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb353e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb353e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb353e0, t=0x14ac51d1bde8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb353e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 24 (Thread 0x14ac4e223700 (LWP 3958876)):
#0  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:78
#1  0x000014ac55ab3530 in ?? () at allocatestack.c:311 from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x000014ac4e223700 in ?? ()
#3  0x0000000000000000 in ?? ()

Thread 23 (Thread 0x14ac50e39700 (LWP 3958852)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac50e38d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35088) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac50e38d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35060) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35060, mutex=0x5563bcb26850, abstime=0x14ac50e38d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac50e38d40, __mutex=<optimized out>, __cond=0x5563bcb35060) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35060) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35060) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35060) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35060) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35060, t=0x14ac50e38de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35060) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 22 (LWP 3958823):
#0  0x0000000000000000 in ?? ()
Backtrace stopped: Cannot access memory at address 0x0

Thread 21 (Thread 0x14ac32610700 (LWP 3928899)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac3260fd40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb3620c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac3260fd40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb361e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb361e0, mutex=0x5563bcb26850, abstime=0x14ac3260fd40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac3260fd40, __mutex=<optimized out>, __cond=0x5563bcb361e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb361e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb361e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb361e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb361e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb361e0, t=0x14ac3260fde8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb361e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 20 (Thread 0x14ac52f25700 (LWP 3958835)):
#0  __lll_lock_wait (futex=futex@entry=0x5563bcb26850, private=0) at lowlevellock.c:52
#1  0x000014ac55ab807b in __pthread_mutex_cond_lock (mutex=mutex@entry=0x5563bcb26850) at ../nptl/pthread_mutex_lock.c:80
#2  0x000014ac55aba699 in __pthread_cond_wait_common (abstime=0x14ac52f24d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35860) at pthread_cond_wait.c:636
#3  __pthread_cond_timedwait (cond=0x5563bcb35860, mutex=0x5563bcb26850, abstime=0x14ac52f24d40) at pthread_cond_wait.c:665
#4  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac52f24d40, __mutex=<optimized out>, __cond=0x5563bcb35860) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#5  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35860) at /usr/include/c++/9/condition_variable:188
#6  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35860) at /usr/include/c++/9/condition_variable:121
#7  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35860) at /usr/include/c++/9/condition_variable:152
#8  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35860) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#9  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35860, t=0x14ac52f24de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#10 0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35860) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#11 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#12 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#13 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 19 (Thread 0x14ac3200d700 (LWP 3928902)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac3200cd40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb36088) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac3200cd40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb36060) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb36060, mutex=0x5563bcb26850, abstime=0x14ac3200cd40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac3200cd40, __mutex=<optimized out>, __cond=0x5563bcb36060) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb36060) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb36060) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb36060) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb36060) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb36060, t=0x14ac3200cde8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb36060) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 18 (Thread 0x14ac5523d700 (LWP 3949999)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x5563bb7b99c8 <ack_receiver+104>) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x5563bb7b9970 <ack_receiver+16>, cond=0x5563bb7b99a0 <ack_receiver+64>) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=cond@entry=0x5563bb7b99a0 <ack_receiver+64>, mutex=mutex@entry=0x5563bb7b9970 <ack_receiver+16>) at pthread_cond_wait.c:647
#3  0x00005563ba894a9a in inline_mysql_cond_wait (mutex=0x5563bb7b9970 <ack_receiver+16>, that=0x5563bb7b99a0 <ack_receiver+64>) at /test/preview-10.10-MDEV-16329-online-alter_opt/include/mysql/psi/mysql_thread.h:1072
#4  Ack_receiver::wait_for_slave_connection (this=0x5563bb7b9960 <ack_receiver>) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/semisync_master_ack_receiver.cc:173
#5  Ack_receiver::run (this=0x5563bb7b9960 <ack_receiver>) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/semisync_master_ack_receiver.cc:229
#6  0x00005563ba894aee in ack_receive_handler (arg=0x5563bb7b9960 <ack_receiver>) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/semisync_master_ack_receiver.cc:35
#7  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#8  0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 17 (Thread 0x14ac30951700 (LWP 3928969)):
#0  0x000014ac555c41a2 in __GI___sigtimedwait (set=set@entry=0x14ac30950ce0, info=info@entry=0x14ac30950d60, timeout=timeout@entry=0x0) at ../sysdeps/unix/sysv/linux/sigtimedwait.c:29
#1  0x000014ac555c420b in __GI___sigwaitinfo (set=set@entry=0x14ac30950ce0, info=info@entry=0x14ac30950d60) at ../sysdeps/unix/sysv/linux/sigwaitinfo.c:25
#2  0x00005563ba605f4a in my_sigwait (code=<synthetic pointer>, sig=0x14ac30950cdc, set=0x14ac30950ce0) at /test/preview-10.10-MDEV-16329-online-alter_opt/include/my_pthread.h:195
#3  signal_hand (arg=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/mysqld.cc:3187
#4  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#5  0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 16 (Thread 0x14ac333d5700 (LWP 3928882)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac333d4d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb36408) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac333d4d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb363e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb363e0, mutex=0x5563bcb26850, abstime=0x14ac333d4d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac333d4d40, __mutex=<optimized out>, __cond=0x5563bcb363e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb363e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb363e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb363e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb363e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb363e0, t=0x14ac333d4de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb363e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 15 (Thread 0x14ac4e022700 (LWP 3958877)):
#0  __lll_lock_wait (futex=futex@entry=0x5563bcb26850, private=0) at lowlevellock.c:52
#1  0x000014ac55ab60a3 in __GI___pthread_mutex_lock (mutex=0x5563bcb26850) at ../nptl/pthread_mutex_lock.c:80
#2  0x00005563bad9a6fe in __gthread_mutex_lock (__mutex=0x5563bcb26850) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:749
#3  std::mutex::lock (this=0x5563bcb26850) at /usr/include/c++/9/bits/std_mutex.h:100
#4  std::unique_lock<std::mutex>::lock (this=0x14ac4e021d90, this=0x14ac4e021d90) at /usr/include/c++/9/bits/unique_lock.h:141
#5  std::unique_lock<std::mutex>::unique_lock (__m=..., this=0x14ac4e021d90) at /usr/include/c++/9/bits/unique_lock.h:71
#6  tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb344e0, t=0x14ac4e021de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:526
#7  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb344e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#8  0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#9  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#10 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 14 (Thread 0x14ac4e826700 (LWP 3958873)):
#0  clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:78
#1  0x000014ac55ab3530 in ?? () at allocatestack.c:311 from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x000014ac4e826700 in ?? ()
#3  0x0000000000000000 in ?? ()

Thread 13 (Thread 0x14ac54838700 (LWP 3958832)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac54837d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35a08) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac54837d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb359e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb359e0, mutex=0x5563bcb26850, abstime=0x14ac54837d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac54837d40, __mutex=<optimized out>, __cond=0x5563bcb359e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb359e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb359e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb359e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb359e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb359e0, t=0x14ac54837de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb359e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 12 (Thread 0x14ac54a39700 (LWP 3958831)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac54a38d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35a88) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac54a38d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35a60) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35a60, mutex=0x5563bcb26850, abstime=0x14ac54a38d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac54a38d40, __mutex=<optimized out>, __cond=0x5563bcb35a60) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35a60) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35a60) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35a60) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35a60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35a60, t=0x14ac54a38de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35a60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 11 (Thread 0x14ac317a3700 (LWP 3928925)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x5563bb7bda60 <mysql_bin_log+3264>) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x5563bb7bda08 <mysql_bin_log+3176>, cond=0x5563bb7bda38 <mysql_bin_log+3224>) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=cond@entry=0x5563bb7bda38 <mysql_bin_log+3224>, mutex=mutex@entry=0x5563bb7bda08 <mysql_bin_log+3176>) at pthread_cond_wait.c:647
#3  0x00005563baa6514a in inline_mysql_cond_wait (mutex=0x5563bb7bda08 <mysql_bin_log+3176>, that=0x5563bb7bda38 <mysql_bin_log+3224>) at /test/preview-10.10-MDEV-16329-online-alter_opt/include/mysql/psi/mysql_thread.h:1072
#4  binlog_background_thread (arg=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/log.cc:10952
#5  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 10 (Thread 0x14ac32a12700 (LWP 3928897)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac32a11d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb3630c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac32a11d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb362e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb362e0, mutex=0x5563bcb26850, abstime=0x14ac32a11d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac32a11d40, __mutex=<optimized out>, __cond=0x5563bcb362e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb362e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb362e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb362e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb362e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb362e0, t=0x14ac32a11de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb362e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 9 (Thread 0x14ac3220e700 (LWP 3928901)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac3220dd40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb36108) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac3220dd40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb360e0) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb360e0, mutex=0x5563bcb26850, abstime=0x14ac3220dd40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac3220dd40, __mutex=<optimized out>, __cond=0x5563bcb360e0) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb360e0) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb360e0) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb360e0) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb360e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb360e0, t=0x14ac3220dde8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb360e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 8 (Thread 0x14ac33bab700 (LWP 3928798)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x5563bb70c7e0 <buf_pool+17312>) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x5563bb70c740 <buf_pool+17152>, cond=0x5563bb70c7b8 <buf_pool+17272>) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=cond@entry=0x5563bb70c7b8 <buf_pool+17272>, mutex=mutex@entry=0x5563bb70c740 <buf_pool+17152>) at pthread_cond_wait.c:647
#3  0x00005563bad0c830 in buf_flush_page_cleaner () at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/buf/buf0flu.cc:2398
#4  0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#5  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 7 (Thread 0x14ac31758700 (LWP 3928962)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac31757d40, clockid=<optimized out>, expected=0, futex_word=0x5563bcb35f8c) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac31757d40, clockid=<optimized out>, mutex=0x5563bcb26850, cond=0x5563bcb35f60) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bcb35f60, mutex=0x5563bcb26850, abstime=0x14ac31757d40) at pthread_cond_wait.c:665
#3  0x00005563bad9a412 in __gthread_cond_timedwait (__abs_timeout=0x14ac31757d40, __mutex=<optimized out>, __cond=0x5563bcb35f60) at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:872
#4  std::condition_variable::__wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=<synthetic pointer>..., __lock=..., this=0x5563bcb35f60) at /usr/include/c++/9/condition_variable:188
#5  std::condition_variable::wait_until<std::chrono::_V2::steady_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x5563bcb35f60) at /usr/include/c++/9/condition_variable:121
#6  std::condition_variable::wait_for<long, std::ratio<1l, 1000l> > (__rtime=..., __lock=..., this=0x5563bcb35f60) at /usr/include/c++/9/condition_variable:152
#7  tpool::thread_pool_generic::wait_for_tasks (this=this@entry=0x5563bcb26740, lk=..., thread_data=thread_data@entry=0x5563bcb35f60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:488
#8  0x00005563bad9a751 in tpool::thread_pool_generic::get_task (this=0x5563bcb26740, thread_var=0x5563bcb35f60, t=0x14ac31757de8) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:541
#9  0x00005563bad9bdb5 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35f60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:586
#10 0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#11 0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 6 (Thread 0x14ac31356700 (LWP 3928964)):
#0  __lll_lock_wait (futex=futex@entry=0x5563bb708440 <buf_pool>, private=0) at lowlevellock.c:52
#1  0x000014ac55ab60a3 in __GI___pthread_mutex_lock (mutex=mutex@entry=0x5563bb708440 <buf_pool>) at ../nptl/pthread_mutex_lock.c:80
#2  0x00005563bad0a73d in inline_mysql_mutex_lock (that=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/include/mysql/psi/mysql_thread.h:752
#3  buf_page_write_complete (request=...) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/buf/buf0flu.cc:405
#4  0x00005563bad428f0 in fil_aio_callback (request=...) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/fil/fil0fil.cc:2874
#5  0x00005563bac2f136 in io_callback (cb=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/os/os0file.cc:3556
#6  0x00005563bad9d019 in tpool::task_group::execute (this=0x5563bcb6b590, t=0x14ac4ce0b4e0) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/task_group.cc:55
#7  0x00005563bad9bda7 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb35e60) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:588
#8  0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#9  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#10 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 5 (Thread 0x14ac4c078700 (LWP 3928923)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x5563bb79252c <COND_manager+44>) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x5563bb792540 <LOCK_manager>, cond=0x5563bb792500 <COND_manager>) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=cond@entry=0x5563bb792500 <COND_manager>, mutex=mutex@entry=0x5563bb792540 <LOCK_manager>) at pthread_cond_wait.c:647
#3  0x00005563ba6fd95b in inline_mysql_cond_wait (mutex=0x5563bb792540 <LOCK_manager>, that=0x5563bb792500 <COND_manager>) at /test/preview-10.10-MDEV-16329-online-alter_opt/include/mysql/psi/mysql_thread.h:1072
#4  handle_manager (arg=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/sql/sql_manager.cc:103
#5  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 4 (Thread 0x14ac4cdba700 (LWP 3928779)):
#0  futex_wake (private=<optimized out>, processes_to_wake=1, futex_word=<optimized out>) at ../sysdeps/nptl/futex-internal.h:364
#1  __pthread_cond_signal (cond=0x5563bcb35860) at pthread_cond_signal.c:94
#2  0x000014ac55993e4d in std::condition_variable::notify_one() () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#3  0x00005563bad9a8ef in tpool::thread_pool_generic::wake (reason=<optimized out>, this=0x5563bcb26740) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:787
#4  tpool::thread_pool_generic::wake (this=0x5563bcb26740, reason=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:776
#5  0x00005563bad9be98 in tpool::thread_pool_generic::submit_task (this=0x5563bcb26740, task=0x14ac4ce04838) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:864
#6  0x00005563bad9dd15 in (anonymous namespace)::aio_uring::thread_routine (aio=0x5563bcb6d690) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/aio_liburing.cc:175
#7  0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#8  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#9  0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 3 (Thread 0x14ac319a4700 (LWP 3928921)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac319a3d90, clockid=<optimized out>, expected=0, futex_word=0x5563bbfbfa48 <COND_checkpoint+40>) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac319a3d90, clockid=<optimized out>, mutex=0x5563bbfbfa60 <LOCK_checkpoint>, cond=0x5563bbfbfa20 <COND_checkpoint>) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=0x5563bbfbfa20 <COND_checkpoint>, mutex=0x5563bbfbfa60 <LOCK_checkpoint>, abstime=abstime@entry=0x14ac319a3d90) at pthread_cond_wait.c:665
#3  0x00005563bab23e8d in inline_mysql_cond_timedwait (abstime=0x14ac319a3d90, mutex=<optimized out>, that=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/include/mysql/psi/mysql_thread.h:1088
#4  my_service_thread_sleep (control=control@entry=0x5563bb6f72c0 <checkpoint_control>, sleep_time=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/maria/ma_servicethread.c:115
#5  0x00005563bab1c585 in ma_checkpoint_background (arg=0x1e) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/maria/ma_checkpoint.c:725
#6  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#7  0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 2 (Thread 0x14ac5524e700 (LWP 3928716)):
#0  futex_abstimed_wait_cancelable (private=<optimized out>, abstime=0x14ac5524ddf0, clockid=<optimized out>, expected=0, futex_word=0x5563bc01058c <COND_timer+44>) at ../sysdeps/nptl/futex-internal.h:320
#1  __pthread_cond_wait_common (abstime=0x14ac5524ddf0, clockid=<optimized out>, mutex=0x5563bc0105a0 <LOCK_timer>, cond=0x5563bc010560 <COND_timer>) at pthread_cond_wait.c:520
#2  __pthread_cond_timedwait (cond=cond@entry=0x5563bc010560 <COND_timer>, mutex=mutex@entry=0x5563bc0105a0 <LOCK_timer>, abstime=abstime@entry=0x14ac5524ddf0) at pthread_cond_wait.c:665
#3  0x00005563bae014d9 in inline_mysql_cond_timedwait (abstime=0x14ac5524ddf0, mutex=0x5563bc0105a0 <LOCK_timer>, that=0x5563bc010560 <COND_timer>) at /test/preview-10.10-MDEV-16329-online-alter_opt/include/mysql/psi/mysql_thread.h:1088
#4  timer_handler (arg=<optimized out>) at /test/preview-10.10-MDEV-16329-online-alter_opt/mysys/thr_timer.c:321
#5  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 1 (Thread 0x14ac32811700 (LWP 3928898)):
#0  buf_flush_LRU_list_batch (n=<synthetic pointer>, n=<synthetic pointer>, max=1536) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/buf/buf0flu.cc:1280
#1  buf_do_LRU_batch (max=1536) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/buf/buf0flu.cc:1374
#2  buf_flush_LRU (max_n=1536) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/buf/buf0flu.cc:1715
#3  0x00005563ba5a8f23 in buf_pool_t::withdraw_blocks (this=this@entry=0x5563bb708440 <buf_pool>) at /usr/include/c++/9/bits/stl_algobase.h:222
#4  0x00005563bad0512d in buf_pool_t::resize (this=this@entry=0x5563bb708440 <buf_pool>) at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/include/buf0buf.h:1546
#5  0x00005563bad0321c in buf_resize_callback () at /test/preview-10.10-MDEV-16329-online-alter_opt/storage/innobase/buf/buf0buf.cc:1972
#6  0x00005563bad9d019 in tpool::task_group::execute (this=0x5563bc006c20 <single_threaded_group>, t=0x5563bc006b80 <buf_resize_task>) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/task_group.cc:55
#7  0x00005563bad9bda7 in tpool::thread_pool_generic::worker_main (this=0x5563bcb26740, thread_var=0x5563bcb36260) at /test/preview-10.10-MDEV-16329-online-alter_opt/tpool/tpool_generic.cc:588
#8  0x000014ac55999de4 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#9  0x000014ac55ab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#10 0x000014ac5569f133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95