Re: PATCH to allow concurrent VACUUMs to not lock each

Hannu Krosing <hannu@skype.net>

From: Hannu Krosing <hannu@skype.net>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Neil Conway <neilc@samurai.com>, pgsql-patches@postgresql.org
Date: 2005-07-03T16:14:38Z
Lists: pgsql-hackers

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On E, 2005-05-23 at 11:42 -0400, Tom Lane wrote:
> Hannu Krosing <hannu@skype.net> writes:
> > I can't think of any other cases where it could matter, as at least the
> > work done inside vacuum_rel() itself seema non-rollbackable.
> 
> VACUUM FULL's tuple-moving is definitely roll-back-able, so it might be
> prudent to only do this for lazy VACUUM.  But on the other hand, VACUUM
> FULL holds an exclusive lock on the table so no one else is going to see
> its effects concurrently anyway.

Ok, this is a new version of the vacuum patch with the following changes
following some suggestions in this thread.

* changed the patch to affect only lazy vacuum 
* moved inVacuum handling to use PG_TRY
* moved vac_update_relstats() out of lazy_vacuum_rel into a separate
  transaction. The code to do this may not be the prettiest, maybe it
  should use a separate struct.

-- 
Hannu Krosing <hannu@skype.net>