Re: Autovacuum integration patch

From: "Matthew T(dot) O'Connor" <matthew(at)zeut(dot)net>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Alvaro Herrera <alvherre(at)surnet(dot)cl>, Patches <pgsql-patches(at)postgresql(dot)org>
Subject: Re: Autovacuum integration patch
Date: 2005-07-05 16:37:08
Message-ID: 42CAB734.1080300@zeut.net
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Tom Lane wrote:

>"Matthew T. O'Connor" <matthew(at)zeut(dot)net> writes:
>
>
>>The current implementation of XID wraparound requires that the vacuum
>>command be run against the entire database, you can not run it on a per
>>table basis and have it work. At least that is my understanding,
>>
>>
>
>No, you're wrong. VACUUMing of individual tables is perfectly good
>enough as far as XID wrap protection goes, it's just that we chose to
>track whether it had been done at the database level. If we tracked it
>in, say, a new pg_class column then in principle you could protect
>against XID wrap with only table-at-a-time VACUUMs. (I think you'd
>still want the pg_database column, but you'd update it to be the minimum
>of the per-table values at the completion of any VACUUM.)
>
>At the time this didn't seem particularly worth the complication since
>no one would be likely to try to do that manually --- but with
>autovacuum handling the work, it starts to sound more realistic.
>

Good, I'm glad I'm wrong on this. This will be another nice advantage
of autovacuum then and should be fairly easy to do. Any thoughts on
this being a change we can get in for 8.1?

Matt

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