Fully replacing ps_status (was Re: [COMMITTERS] pgsql: Add GUC update_process_title to control whether 'ps' display is)

momjian(at)postgresql(dot)org (Bruce Momjian) writes:
> Add GUC update_process_title to control whether 'ps' display is updated
> for every command, default to on.

It strikes me that the ps_status support provides one important bit of
information that is currently hard to get elsewhere; specifically, the
"waiting" flag that gets added while blocked on a lock. You can find
out if a process is blocked by looking in pg_locks, but that's a fairly
expensive probe in itself and then you have to join to pg_stat_activity
to make any sense of it. I wonder if we should add a "waiting" boolean
column to pg_stat_activity? Given the new implementation of
pg_stat_activity, updating such a flag would be pretty cheap.

regards, tom lane