Hi MJ,
5) verify from mariadb: SHOW GLOBAL VARIABLES LIKE 'jemalloc%';
I think you mean: SHOW GLOBAL VARIABLES LIKE 'version_malloc_library'; Or alternatively: select @@version_malloc_library; Karl On Wed, 19 Mar 2025 at 14:18, sacawulu via discuss < discuss@lists.mariadb.org> wrote:
Hi,
I've followed this thread with great interest.
Just to confirm, if we also want to change to tmalloc, running on RHEL8/9, a quick google tells me that the steps are:
1) sudo yum install gperftools-libs
2) rpm -ql gperftools-libs | grep tcmalloc
(save the file/path)
3) edit the mariadb systemctl file:
sudo systemctl edit mariadb and add [Service] Environment="LD_PRELOAD=/usr/lib64/libtcmalloc_minimal.so.4"
4) restart mysql
5) verify from mariadb: SHOW GLOBAL VARIABLES LIKE 'jemalloc%';
6) optimize mariadb: [mariadb] malloc-lib=/usr/lib64/libtcmalloc_minimal.so.4
Or is there a simpler/more standard method?
MJ
On 3/17/25 15:48, Derick Turner via discuss wrote:
System (default) made zero difference. TC Malloc, on the other hand, has been a winner! The server which I switched this to has sat on 15/16GB while the rest have continued to consume all of the memory.
I'll switch over all of the servers to use this and I will put the other settings back to where they originally were. (30GB RAM server with 22GB innodb_buffer_pool)
Thank you for you help with this. It is very much appreciated!
Kind regards
Derick
On 17/03/2025 12:13, Derick Turner via discuss wrote:
Thanks for the response Sergie!
I switched over to jemalloc in an effort to try and resolve the issue - as I had seen some posts suggesting that as a potential option to deal with memory leaks. I've removed this from one of the servers which has set it back to system. On the next rotation of restarts I'll change another to tmalloc, so I can track any differences between the three.
In case this is also related: we do not get any instances in the logs for InnoDB: Memory pressure events. The listener is being started on all instances. I'm assuming this is where the memory in the InnoDB cache is being released back to the OS? There were logged instances of this running when all of the memory was consumed and the system was starting to use swap. However, OOM killer eventually kicked in and killed the DB process, which is too much of a risk for us to have happen at the moment.
Kind regards
Derick
On 17/03/2025 11:55, Sergei Golubchik wrote:
Hi, Derick,
According to your SHOW GLOBAL STATUS
Memory_used 15460922288
That is the server thinks it uses about 15GB
The difference could be due to memory fragmentation, when the server frees the memory, but it cannot be returned to the OS. In this case using a different memory allocator could help (try system or tcmalloc).
Regards, Sergei Chief Architect, MariaDB Server and security@mariadb.org
On Mar 17, Derick Turner via discuss wrote:
Hi all,
I was pointed to this list from a question I raised on StackExchange (https://dba.stackexchange.com/questions/345743/why-does-my-mariadb- application-use-more-memory-than-configured)
I have a cluster of MariaDB (11.4.5) primary/primary servers running on Ubuntu. I updated the OS on Saturday to 24.04 from 22.04 (and patched the DB to the 11.4.5 noble version) as we were occasionally hitting an OOM event which was causing the database process to be killed. Since then, the DB process takes all of the available server memory before being killed by the OOM killer.
DB is configured to use about 15GB of RAM (from config calculations) Servers currently have 50GB of RAM and 95% of this is used within about an hour an a half.
Link to document with configuration settings, global status, mariadb.service override and InnoDB status is here - https://docs.google.com/spreadsheets/ d/1ev9KRWP8l54FpRrhFeX4uxFhJnOlFkV4_vTCZWipcXA/edit?usp=sharing
Any help would be gratefully received.
Thanks in advance.
Derick
-- Derick Turner - He/Him
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