Re: Autovacuum / full vacuum

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Chris Browne <cbbrowne(at)acm(dot)org>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Autovacuum / full vacuum
Date: 2006-01-17 19:32:52
Message-ID: 20592.1137526372@sss.pgh.pa.us
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Chris Browne <cbbrowne(at)acm(dot)org> writes:
> alvherre(at)alvh(dot)no-ip(dot)org (Alvaro Herrera) writes:
>> Even a database-wide vacuum does not take locks on more than one table.
>> The table locks are acquired and released one by one, as the operation
>> proceeds.

> Has that changed recently? I have always seen "vacuumdb" or SQL
> "VACUUM" (without table specifications) running as one long
> transaction which doesn't release the locks that it is granted until
> the end of the transaction.

You sure? It's not supposed to, and watching a database-wide vacuum
with "select * from pg_locks" doesn't look to me like it ever has locks
on more than one table (plus the table's indexes and toast table).

regards, tom lane

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