| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | "Scott Marlowe" <scott(dot)marlowe(at)gmail(dot)com> |
| Cc: | "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov>, alvherre(at)commandprompt(dot)com, duanlg(at)nec-as(dot)nec(dot)com(dot)cn, pgsql-performance(at)postgresql(dot)org, "Matt Smiley" <mss(at)rentrak(dot)com> |
| Subject: | Re: too many clog files |
| Date: | 2008-09-10 17:42:40 |
| Message-ID: | 2257.1221068560@sss.pgh.pa.us |
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| Lists: | pgsql-performance |
"Scott Marlowe" <scott(dot)marlowe(at)gmail(dot)com> writes:
> On Wed, Sep 10, 2008 at 8:58 AM, Kevin Grittner
> <Kevin(dot)Grittner(at)wicourts(dot)gov> wrote:
>> Some of my high-volume databases don't quite go back to 0000, but this
>> does seem to be a problem. I have confirmed that VACUUM FREEZE on all
>> but template0 (which doesn't allow connections) does not clean them
>> up. No long running transactions are present.
> I have a pretty high volume server that's been online for one month
> and it had somewhere around 53, going back in order to 0000, and it
> was recently vacuumdb -az 'ed. Running another one. No long running
> transactions, etc...
The expected behavior (in 8.2 and newer) is to maintain about
autovacuum_freeze_max_age transactions' worth of clog; which is to say
about 50MB at the default settings. If you've got significantly more
than that then we should look more closely.
I don't remember what the truncation rule was in 8.1, so I can't speak
to the OP's complaint.
regards, tom lane
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