If there are no queries on database I see number of context switches from ~900 to ~1500.
I checked our monitoring based on node_exporter, Prometheus and Grafana and when this "drowsiness" of sessions happens I see number of context switches from ~10 000 to ~25 000 with a few peeks ~28 000.
But similar numbers or even slightly higher I see also in other cases of high load on the database and they did not caused any "drowsy" sessions. In fact monitoring does not show any significant differences between cases with "drowsy" sessions and without them...If you have some advices about what else to monitor I will add.
Josef Machytka <josef.machytka@gmail.com> writes: > sorry, here is file with sample - basically several group by aggregations > over different partitioned tables have been locked in this "drowsy" state
The amount of time being spent in the kernel is strikingly high. I wonder if you're seeing some variant of the old "context swap storm" problem. Try watching the output of "vmstat 1" for awhile to see if the cs rate is high.
