Horton

Re: First steps with 8.3 and autovacuum launcher

Simon Riggs <simon@2ndquadrant.com>

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From: Simon Riggs <simon@2ndquadrant.com>
To: Alvaro Herrera <alvherre@commandprompt.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Gregory Stark <stark@enterprisedb.com>, Guillaume Smet <guillaume.smet@gmail.com>, "Matthew T. O'Connor" <matthew@zeut.net>, Heikki Linnakangas <heikki@enterprisedb.com>, Stefan Kaltenbrunner <stefan@kaltenbrunner.cc>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2007-10-05T12:27:54Z
Lists: pgsql-hackers 
On Thu, 2007-10-04 at 17:33 -0400, Alvaro Herrera wrote:
> Simon Riggs escribió:
> 
> > Seems like we don't need to mess with the deadlock checker itself.
> > 
> > We can rely on the process at the head of the lock wait queue to sort
> > this out for us. So all we need do is look at the isAutovacuum flag on
> > the process that is holding the lock we're waiting on. If it isn't an
> > autoANALYZE we can carry on with the main deadlock check. We just need a
> > new kind of deadlock state to handle this, then let ProcSleep send
> > SIGINT to the autoANALYZE and then go back to sleep, waiting to be
> > reawoken when the auotANALYZE aborts.
> 
> Ok, I think this makes sense.
> 
> I can offer the following patch -- it makes it possible to determine
> whether an autovacuum process is doing analyze or not, by comparing the
> PGPROC of the running WorkerInfo list (the list has at most
> max_autovacuum_workers entries, so this is better than trolling
> ProcGlobal).

Looks OK to me, thanks for noticing I glossed over the bit about how to
tell whether it was an auto-ANALYZE.

-- 
  Simon Riggs
  2ndQuadrant  http://www.2ndQuadrant.com