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  1. MariaDB Server
  2. MDEV-21390

lock_print_info_summary() should work even when trx_sys.mutex is locked

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      The lock_print_info_summary() function currently requires trx_sys.mutex, since it calls the trx_sys_get_max_trx_id() function.

      https://github.com/mariadb/server/blob/mariadb-10.2.30/storage/innobase/lock/lock0lock.cc#L4910

      https://github.com/MariaDB/server/blob/mariadb-10.2.30/storage/innobase/include/trx0sys.ic#L400

      This causes a couple different problems:

      1.) This means that SHOW ENGINE INNODB STATUS will hang if it can't lock trx_sys.mutex.

      2.) If there is a long semaphore wait on trx_sys.mutex, then the sync_array_print_long_waits() function will be called, which will set srv_print_innodb_monitor. This will cause the InnoDB monitor thread to call the lock_print_info_summary() function, so that the InnoDB status information will be written to the error log. If the lock_print_info_summary() function requires trx_sys.mutex, then the monitor thread will not be able to write the InnoDB status information to the error log.

      https://github.com/MariaDB/server/blob/mariadb-10.2.30/storage/innobase/sync/sync0arr.cc#L1081

      https://github.com/MariaDB/server/blob/mariadb-10.2.30/storage/innobase/srv/srv0srv.cc#L1756

      Both of the above problems cause issues when users are attempting to diagnose long semaphore waits on trx_sys.mutex.

      Maybe the lock_print_info_summary() function should print dirty data with a warning if it can't lock trx_sys.mutex?

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          relates to

          Task - A task that needs to be done. MDEV-14756 Remove trx_sys_t::rw_trx_list

          • Major - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-17237 thread IDs are printed in different formats in different sections of SHOW ENGINE INNODB STATUS output

          • Major - Major loss of function.
          • Open

          Bug - A problem which impairs or prevents the functions of the product. MDEV-17238 Document special thread IDs used in SHOW ENGINE INNODB STATUS output

          • Major - Major loss of function.
          • Open

          Task - A task that needs to be done. MDEV-18391 Print ENGINE INNODB STATUS in machine parsable format

          • Major - Major loss of function.
          • Open

          Bug - A problem which impairs or prevents the functions of the product. MDEV-18429 Consistent non-locking reads do not appear in TRANSACTIONS section of SHOW ENGINE INNODB STATUS

          • Major - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-18572 Thread executing DROP TABLE listed twice in SHOW ENGINE INNODB STATUS output

          • Major - Major loss of function.
          • Open

          Task - A task that needs to be done. MDEV-18582 Port status variables related to SHOW ENGINE INNODB STATUS from XtraDB to InnoDB in 10.2+

          • Major - Major loss of function.
          • Closed

          Task - A task that needs to be done. MDEV-18698 Show InnoDB's internal background threads in SHOW ENGINE INNODB STATUS

          • Major - Major loss of function.
          • Open

          Bug - A problem which impairs or prevents the functions of the product. MDEV-21566 Lock monitor doesn't print a name for RW-latches

          • Major - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-22087 Increase buffer size for query in SHOW ENGINE INNODB STATUS output

          • Major - Major loss of function.
          • Open

          Bug - A problem which impairs or prevents the functions of the product. MDEV-21330 Lock monitor doesn't print a semaphore's last reserved thread in non-debug builds and INFORMATION_SCHEMA.INNODB_SYS_SEMAPHORE_WAITS is totally broken

          • Critical - Crashes, loss of data, severe memory leak.
          • Closed

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              marko Marko Mäkelä
              GeoffMontee Geoff Montee (Inactive)
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                Updated:
                Resolved:

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