MongoDB Slowness issue

MongoDB Percona Server for MongoDB
1

We have been using Percona Mongo version 7.0.14-8 on 3 nodes as a cluster on RHEL 9.6 with kernel version : 5.14.0-570.23.1.el9_6.x86_64. Recently, the kernel on one of the DR node is upgraded as part of OS patching activity and the recent kernel upgraded to 5.14.0-570.41.1.el9_6.x86_64. Post which the query executions are taking longer time. For example, out of 500 queries, 400 were running on 100ms, 50 on 200ms and 50 on 300 ms, post upgrade, it looks like 250 queries are running within 100ms, 100 on 200ms, 150 on 300ms and 100 more than 400 ms (milliseconds).

Case raised with RedHat to find any bug in the upgrade, however they do not see anything. Can we have this checked. Did anyone face this similar issue ?

2

Do you happen to know if you have any other changes from the application side that might affect it?

I would definitely compare the metrics before and after the upgrade to see if anything strange.

Like, have a look at the slow queries to see if they are picking up the same indexes as before and similar keys and docs examined there.