Re: RFC: replace pg_stat_activity.waiting with something more descriptive

Andres Freund <andres@anarazel.de> writes:
> On 2015-06-25 10:01:39 -0400, Tom Lane wrote:
>> The problem with the query analogy is that it's possible to tell whether
>> the query is active or not, by looking at the status column.  We need to
>> avoid a situation where you can't tell if the wait status is current or
>> merely the last thing waited for.

> Well, that's what the 'waiting' column would be about in the proposal I'm
> commenting about.

To do that, we'd have to change the semantics of the 'waiting' column so
that it becomes true for non-heavyweight-lock waits.  I'm not sure whether
that's a good idea or not; I'm afraid there may be client-side code that
expects 'waiting' to indicate that there's a corresponding row in
pg_locks.  If we're willing to do that, then I'd be okay with
allowing wait_status to be defined as "last thing waited for"; but the
two points aren't separable.
        regards, tom lane