[debian-mysql] Bug#1027337: Bug#1027337: mariadb-server-10.5: Huge increase in memory consumption (leak?) since upgrade from 10.5.15 to 10.5.18

[fmaesen]

Hi all, there is an upstream release 10.5.19 with hopefully a fix:

https://mariadb.com/kb/en/mariadb-10-5-19-release-notes/


On Thu, 12 Jan 2023 08:55:06 +0000 Matteo Valsasna <MValsasna at pdxeng.ch>
wrote:
> Thanks a lot Faustin
>
>
>
> I found an useful description of MDEV-29988 in a comment to one of its
duplicates, and it matches quite well our application scenario for the
database connection that cause the memory leak according to
information_schema.PROCESSLIST.memory_used
> (prepared statements executed maaany times, string comparisons)
>
> we reproduced the issue on a test machine, and we will try to downgrade
to 10.5.15
>
>
>
> MAtteo
>
>
>
>
https://jira.mariadb.org/browse/MDEV-30096?focusedCommentId=243814&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-243814
>
> [serg]Sergei Golubchik<
https://jira.mariadb.org/secure/ViewProfile.jspa?name=serg> added a comment
- 2022-11-28 22:20
>
> Yes, <https://jira.mariadb.org/browse/MDEV-29988>  was in 10.6.11 too.
But let's first check the preconditions:
>
>   *   you use prepared statements
>   *   you prepare once and then execute many thousands of times before
deallocating the statement
>   *   your statements contains a string comparison with strings in
different (but compatible) character sets (e.g. utf8 and latin1).
>
> if all that matches your use case you could be affected by <
https://jira.mariadb.org/browse/MDEV-29988> . If you do, then
>
>   *   every execution of such a prepared statements will allocate more
memory
>   *   all memory will be freed when a statements is deallocated
(explicitly or when the client disconnects)
>   *   time to deallocate a prepared statement is proportional to the
number of times it was executed
>
> and workarounds could be
>
>   *   deallocate prepared statements more often
>   *   rewrite statements to avoid comparing strings in different
character sets
>
> or wait for the next release that will have it fixed
>
>
>
> On Tue, 10 Jan 2023 13:36:02 +0100 Faustin Lammler <faustin at fala.red>
wrote:
> > Hi,
> > first of all, thank you all for the excellent (and detailed) report!
> >
> > I don't see anything that could be related with Debian packaging of
> > MariaDB and so I suggest you check directly upstream.
> >
> > I have searched into https://jira.mariadb.org and the closest report
> > that I can come with is https://jira.mariadb.org/browse/MDEV-29988. I do
> > not forward this bug report to it because I am not sure that this is the
> > same problem.
> >
> > There is also https://jira.mariadb.org/browse/MDEV-29097 that may give
> > some ideas on how to find a workaround until the next release happen.
> >
> > Cheers!
> >
> > --
> > Faustin
> > GPG: F652 BCD1 1AA8 8975 F010 48A5 390A 2F27 832A 5C79
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