Bug #108324 | Easy to OOM mysqld with innodb_dedicated_server=ON and Innodb cluster | ||
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Submitted: | 29 Aug 2022 16:03 | Modified: | 8 Sep 2022 9:52 |
Reporter: | Jay Janssen | Email Updates: | |
Status: | Not a Bug | Impact on me: | |
Category: | MySQL Server | Severity: | S3 (Non-critical) |
Version: | 8.0.30 | OS: | Red Hat |
Assigned to: | MySQL Verification Team | CPU Architecture: | x86 |
[29 Aug 2022 16:03]
Jay Janssen
[6 Sep 2022 4:32]
MySQL Verification Team
Hi, I am not sure how "easy" you can OOM the server. I tried for a while and could not do it on a much smaller server? Can you share full config? thanks
[7 Sep 2022 13:11]
Jay Janssen
The configuration is not complex at all. [mysqld] datadir=/data/mysql socket=/data/mysql/mysql.sock log-error=/var/log/mysqld.log pid-file=/var/run/mysqld/mysqld.pid !includedir /etc/my.cnf.d skip-name-resolve # Innodb innodb-dedicated-server=on # Replication binlog_expire_logs_seconds=604800 # Cluster / Group replication loose_group_replication_paxos_single_leader=ON This is using Amazon Linux 2 with no tuning. I've added innodb-buffer-pool-size=21565865984, but still had OOM issues. When I set sysctl vm.swappiness=0, and oom_score_adj=-1000 things seem more stable. I'm wondering if I should try removing my innodb-buffer-pool-size override.
[7 Sep 2022 14:39]
Jay Janssen
Assuming your environment is properly setting swappiness, I'd be fine closing this bug.
[8 Sep 2022 9:52]
MySQL Verification Team
Hi, > When I set sysctl vm.swappiness=0, and oom_score_adj=-1000 things seem > more stable. > I'm wondering if I should try removing my innodb-buffer-pool-size override. IMHO you should always have innodb_buffer_pool_size in the config and have it not higher than 70% of the total RAM. > Assuming your environment is properly setting swappiness, I personally run 0 or 1. Linux kernel changes behavior for swappiness through time and even today different distros can have different behavior so for me the safe value on MySQL Server machines is 0 or 1 (I prefer 0). Especially on EC2 I had some nasty issues irrelevant from MySQL with swappiness so for EC2 I personally force 0. On old kernel I used 10 but these days 0 is mine preferred value on servers where MySQL is running. > I'd be fine closing this bug. Ok. Closed, as this is both configuration issue and possible issue with Amazon linux. kind regards