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04-18-2008, 08:30 AM
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 autovacuum? Hi. I have a mostly insert/select database, so vacumming is generally not much needed.. but among the tables I have one which is used as a message-queue so a lot of insert/updates/deletes on small simple records on that one. How do I check that autovacumm is running at all? (I think i have enabled it in /etc/postgresql/8.2/*/postgresql.conf ). select relname,last_autovacuum,last_autoanalyze from pg_stat_user_tables where relname = 'job'; relname | last_autovacuum | last_autoanalyze ---------+-------------------------------+------------------------------- job | 2008-04-16 07:19:24.832413+02 | 2008-04-17 01:40:05.242914+02 So it seems to be running. But shouldn't it hit the table a lot more? How do I check that it is somehow near optimal? -- Jesper -- Sent via pgsql-admin mailing list (pgsql-admin@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-admin      |
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04-18-2008, 08:30 AM
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| Re: autovacuum? On Fri, Apr 18, 2008 at 1:18 AM, Jesper Krogh <jesper@krogh.cc> wrote: > > > So it seems to be running. Yes. > But shouldn't it hit the table a lot more? That depends on your autovac settings, especially autovacuum_vacuum_scale_factor. If it is set to 0.2 (which is default), then autovacuum would hit the table whenever the percentage of dead tuples is at least 20%. Again, the percentage of dead tuples depends on your table size and rate of insert/update/delete. > How do I check that it is somehow near optimal? > Again that depends on how much table bloat you can sustain. If you don't want the table to bloat too much, you can set aggressive settings for autovac. But that would trigger autovac more often and may have performance implication on your other concurrent queries. Thanks, Pavan -- Pavan Deolasee EnterpriseDB http://www.enterprisedb.com -- Sent via pgsql-admin mailing list (pgsql-admin@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-admin |
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