2/2 3. leverage system views: I think it would make sense to add “and state = ‘active’” in the query. As if not “active” the query will show the last wait event when the session “was” active.

1/2 Thanks Kellyn! Yeah that looks good, thanks! Just 3 remarks ;-) : 1. for most PostgreSQL databases: for PostgreSQL databases versions greater or equal to 10.
2. s/Drovout/Drouvot

wait_event_type is documented here www.postgresql.org/docs/current... and here www.postgresql.org/docs/current... It's not named "class" as on Oracle but that's the same i.e a way to group by type/category.

@dbakevlar.bsky.social not sure what you mean by "There is no official grouping into wait classes". You can see the wait event type as the wait class:

Je ne suis donc pas le seul ! ;-)

Unless the others close at 9pm? ;-)