From: Mindaugas Riauba <mind@bi.lt>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-performance@postgresql.org
Subject: Re: How to avoid database bloat
Date: Thu, 2 Jun 2005 17:24:47 +0300
Message-ID: <02db01c5677e$d43d3b10$f20214ac@bite.lt> (raw)
References: <00d501c5667d$8cc12320$f20214ac@bite.lt>
<13878.1117636799@sss.pgh.pa.us>
<018601c56744$9d5aae50$f20214ac@bite.lt>
<13178.1117719939@sss.pgh.pa.us>
> >> First thing I'd suggest is to get a more detailed idea of exactly
> >> what is bloating --- which tables/indexes are the problem?
>
> > I think the most problematic table is this one. After vacuum
full/reindex
> > it was 20MB in size now (after 6 hours) it is already 70MB and counting.
>
> AFAICT the vacuum is doing what it is supposed to, and the problem has
> to be just that it's not being done often enough. Which suggests either
> an autovacuum bug or your autovacuum settings aren't aggressive enough.
-D -d 1 -v 1000 -V 0.5 -a 1000 -A 0.1 -s 10
That is autovacuum settings. Should be aggressive enough I think?
> Which PG version is this exactly? Some of the earlier autovacuum
> releases do have known bugs, so it'd be worth your while to update
> if you're not on the latest point release of your series.
8.0.3
> I don't know much about autovacuum settings, but if you'll show what
> you're using someone can probably comment on them.
And what in vacuum verbose output suggests that vacuum is not done
often enough? Current output (table is 100MB already) is below.
Thanks,
Mindaugas
$ vacuumdb -v -z -U postgres -t queue database
INFO: vacuuming "queue"
INFO: index "queue_msg_id_pk" now contains 302993 row versions in 18129
pages
DETAIL: 102763 index row versions were removed.
1 index pages have been deleted, 1 are currently reusable.
CPU 0.87s/0.46u sec elapsed 76.40 sec.
INFO: index "queue_next_retry" now contains 310080 row versions in 9092
pages
DETAIL: 102763 index row versions were removed.
675 index pages have been deleted, 658 are currently reusable.
CPU 0.38s/0.31u sec elapsed 79.47 sec.
INFO: index "queue_recipient_idx" now contains 323740 row versions in 2900
pages
DETAIL: 102763 index row versions were removed.
0 index pages have been deleted, 0 are currently reusable.
CPU 0.07s/0.27u sec elapsed 9.06 sec.
INFO: "queue": removed 102763 row versions in 9623 pages
DETAIL: CPU 0.16s/0.39u sec elapsed 29.26 sec.
INFO: "queue": found 102763 removable, 292342 nonremovable row versions in
12452 pages
DETAIL: 14 dead row versions cannot be removed yet.
There were 183945 unused item pointers.
0 pages are entirely empty.
CPU 1.56s/1.51u sec elapsed 194.39 sec.
INFO: analyzing "queue"
INFO: "queue": scanned 3000 of 12452 pages, containing 72850 live rows and
7537 dead rows; 3000 rows in sample, 302376 estimated total rows
VACUUM
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To: pgsql-performance@postgresql.org
Cc: mind@bi.lt, tgl@sss.pgh.pa.us
Subject: Re: How to avoid database bloat
In-Reply-To: <02db01c5677e$d43d3b10$f20214ac@bite.lt>
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