Re: Let's invent a function to report lock-wait-blocking PIDs

Robert Haas escribió:
> On Wed, Mar 20, 2013 at 2:02 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> > I was just looking into why the -DCLOBBER_CACHE_ALWAYS buildfarm
> > critters aren't managing to run the new "timeouts" isolation test
> > successfully, despite very generous timeouts.  The answer is that
> > 2 seconds isn't quite enough time to parse+plan+execute the query
> > that isolationtester uses to see if the current test session is
> > blocked on a lock, if CLOBBER_CACHE_ALWAYS is on.  Now, that query
> > is totally horrible:

> > In the isolationtester use-case, we'd get the right answer by testing
> > whether this function's result has any overlap with the set of PIDs of
> > test sessions, ie
> >
> >         select pg_blocking_pids($1) && array[pid1, pid2, pid3, ...]
>
> Sounds excellent.

Yeah, I have looked at that query a couple of times wondering how it
could be improved and came up blank.  Glad you had a reason to be in the
area.

--
Álvaro Herrera                http://www.2ndQuadrant.com/
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