Mastering PostgreSQL 10

Using additional information in pg_stat_activity

Before PostgreSQL 10.0, pg_stat_activity only contained information about normal backend processes serving end users (connections). However, this has changed. Since PostgreSQL 10.0, a lot more information is exposed. It is possible to figure out what these other system processes are doing.

The following listing shows the content of pg_stat_activity on an idle database instance:

test=# \x 
Expanded display is on. test=# SELECT pid, wait_event_type, wait_event, backend_type  
   FROM  pg_stat_activity ; -[ RECORD 1 ]---+-------------------- pid | 12159 wait_event_type | Activity wait_event | AutoVacuumMain backend_type | autovacuum launcher -[ RECORD 2 ]---+-------------------- pid | 12161 wait_event_type ...