Have you checked whether: 1) Your theoretical max memory usage exceeds ~90% of RAM?
Start with: SELECT ((@@innodb_buffer_pool_size + @@innodb_log_buffer_size + @@key_buffer_size + @@query_cache_size + @@max_connections * (@@bulk_insert_buffer_size + @@join_buffer_size + @@read_buffer_size + @@read_rnd_buffer_size + @@sort_buffer_size + @@tmp_table_size)) / 1024 / 1024 / 1024) AS max_memory_GB; 2) Are you using /tmp/ for temporary tables and is your /tmp/ mounted as tmpfs? On Thu, 7 Sep 2023, 14:17 Marco Dickert - evolver group via discuss, < [email protected]> wrote: > Hi Sergei, > > a quick follow-up on this topic. We still experience the RAM usage > problems. > After your suggestion to upgrade MariaDB to the latest 10.5, we switched > to the > community repository for debian > (https://dlm.mariadb.com/repo/mariadb-server/...). This is what we did > since: > > * upgrade MariaDB to 10.5.21 > * upgrade MariaDB to latest 10.6 > * switch to jemalloc2 library on 10.6 > * upgrade MariaDB to latest 10.11 (system malloc) > * switch to jemalloc2 library on 10.11 > > We ran every setup for several days, to check if there is any improvement > on the > RAM usage front, but nothing really changed. We noticed that when we use > jemalloc2, the gaps between the OOM-kills is a bit bigger, but the general > problem persists. Also, we couldn't determine a real "trigger" for the > behaviour. > > Our application has a very regular usage pattern. There is a peak of > activity in > the morning (08-10 a.m.), a steady baseline until about 10 p.m., and very > low > activity at night (see the attached graph 1). The OOM incidents happen > both in > the morning and in the evening. The second graph shows the RAM usage (RSS) > of > the mariadbd process over the last three days. Third, I attached a text > file > showing the timestamps of the OOM kills. > > Unfortunately we are not quite sure which is the best way to debug this > further. > We took a look at our queries, but couldn't determine a problem there. Our > frontend application does not use queries with JOINs. Every request > triggers > only a few SELECTs and UPDATEs. Two tables we write to are relatively big > (10 > and 12 GB). On average every frontend request triggers about 4-8 queries. > > Are there any other metrics we could observe to get a hint to why this > happens? > Or has anyone another idea on how to get a grip on what is going on? > > Am 2023-08-04 19:13:44 schrieb Sergei Golubchik: > > Hi, Marco, > > > > Please, try the latest 10.5 release, there were few bugs with those > > symptoms fixed. > > > > On Aug 04, Marco Dickert - evolver group via discuss wrote: > > > Hi folks, > > > > > > we experience a RAM issue with MariaDB (version > > > 10.5.19-MariaDB-0+deb11u2-log) on a standard Debian bullseye system. > > > The problem is that over time MariaDB uses more and more RAM, until > > > the kernel's oom-killer terminates it. > > > > > Regards, > > Sergei > > VP of MariaDB Server Engineering > > and [email protected] > > -- > Kind regards, > Marco Dickert > _______________________________________________ > discuss mailing list -- [email protected] > To unsubscribe send an email to [email protected] >
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