On Thu, Sep 08, 2022 at 04:37:00PM +0800, BeginnerC wrote: > Hello community, > I am checking my pg_stat_activity view,but something confused me. > Just like this: > > postgres=# SELECT wait_event_type, wait_event FROM pg_stat_activity; > wait_event_type | wait_event > -----------------+--------------------- > Activity | AutoVacuumMain > Activity | LogicalLauncherMain > | > Activity | BgWriterHibernate > Activity | CheckpointerMain > Activity | WalWriterMain > (6 rows) > > As you can see, the third row is empty,but I don't know why. > Can anyone provide some solution to me? > Thanks in advance! Please do: \pset null '-- null --' SELECT wait_event_type, wait_event FROM pg_stat_activity; it will most likely show -- null -- in these fields. which means values in these columns are null.SELECT wait_event_type, wait_event FROM pg_stat_activity; You can find more about this/these backends by doing: select * from pg_stat_activity where wait_event_type is null \gx depesz
