High memory & CPU usage after upgrading to 5.7.20

On CentOS 7 upgraded from Percona MySQL 5.7.17 to MySQL 5.7.20 and then suddenly start getting alerts on CPU high usage & memory spikes.
It is 8GB RAM CentOS 7 with innodb buffer pool size of 4GB and 32 pool instances.

What change in MySQL 5.7.20 might be causing this spike - no changes in my.cnf.


I’d say it’s almost impossible to pick something from the change log and attribute your symptoms to the release. I do however think that the best way to work it out is to post before and after graphs/monitoring data to enable some help showing you what’s actually changed. Perhaps the restart of your instance dropped some ad-hoc configuration that was made and not persisted to the config files. Do you have some record of what the global variables were set at before you upgraded (not the my.cnf)?

The issue is gone now. The reason was we only upgraded one package (Percona Server 5.7) through yum and left many that were listed through “yum check-update”. So we requested our system admin to run “yum update” and after it was done, the memory went down. We could verify it from our Grafana graphs.

Thanks for the update, it might well help other users. Glad the issue is resolved!