Details
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Bug
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Status: Closed (View Workflow)
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Critical
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Resolution: Fixed
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10.0(EOL), 10.1(EOL), 10.2(EOL)
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MariaDB 10.1.8 or MariaDB 10.1.18 on debina 8
Description
dual master with parallel replication memory leak in write master
(slave_parallel_threads=8)
master(active)<----->master(standby)
if write in master(active) frequently, master(active) use memory more and more and then physical memory give out,2G physical memory per day,and then swap give up，the OS OOM Killer killed mysqld process.
if you stop slave on master(active) before OOM Killer killed,the OS reclaim a lot of physical memory
Attachments
Activity
Hm, that's a good point actually.
Gtid_list_log_event::do_apply_event() is one of the few functions that run
on the active master in circular replication. And it modifies tables, so
could be using thd->mem_root. And on standby slave,
Query_log_event::do_apply_event() will run all the time to free the
thd->mem_root - but not on the active master.
I'll try to come up with a patch.
You are absolutely right, Gtid_list_log_event::do_apply_event() is missing free_root(), and this is causing a memory leak.
Very nice catch, thanks!
I was able to reproduce the leak with the attached (crude) mysql-test-run.pl script. It is fixed by this patch, which just adds the missing free_root():
http://lists.askmonty.org/pipermail/commits/2017-January/010445.html
https://github.com/MariaDB/server/blob/74d52ded721d8d39bfb25d18a0b0b8ea8a7af884/sql/log_event.cc
Gtid_list_log_event::do_apply_event function not use free_root(thd->mem_root, MYF(MY_KEEP_PREALLOC));
i don't ensure.