Hi, > > I'd like to propose exposing the start time of the current heavyweight lock > wait in pg_stat_activity, perhaps as: > > lock_wait_start timestamptz > > pg_stat_activity currently tells us that a backend is waiting on a lock > through wait_event_type and wait_event, but not when that wait started.
pg_locks.waitstart already provides this information. Any reason that is not sufficient? pg_locks is meant to be joined with pg_stat_activity anyhow. The two views aren't read from the same snapshot, so they can be out of sync. But that's already true inside pg_stat_activity, as the docs say: "To keep the reporting overhead low, the system does not attempt to synchronize different aspects of activity data for a backend. As a result, ephemeral discrepancies may exist between the view's columns." The same will be true even if we add waitstart to pg_stat_activity. -- Sami Imseih Amazon Web Services (AWS)
