| From: | Bruce Momjian <bruce(at)momjian(dot)us> |
|---|---|
| To: | Andrew Dunstan <andrew(at)dunslane(dot)net> |
| Cc: | Gregory Stark <stark(at)enterprisedb(dot)com>, Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Subject: | Re: Visibility map, partial vacuums |
| Date: | 2009-01-15 01:31:11 |
| Message-ID: | 200901150131.n0F1VBa10679@momjian.us |
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| Lists: | pgsql-hackers |
Andrew Dunstan wrote:
>
>
> Bruce Momjian wrote:
> > Would someone tell me why 'autovacuum_freeze_max_age' defaults to 200M
> > when our wraparound limit is around 2B?
> >
>
> Presumably because of this (from the docs):
>
> "The commit status uses two bits per transaction, so if
> autovacuum_freeze_max_age has its maximum allowed value of a little less
> than two billion, pg_clog can be expected to grow to about half a gigabyte."
Oh, that's interesting; thanks.
--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ If your life is a hard drive, Christ can be your backup. +
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