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@ -1,4 +1,4 @@ |
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<!-- $PostgreSQL: pgsql/doc/src/sgml/maintenance.sgml,v 1.76 2007/07/18 03:39:01 momjian Exp $ --> |
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<!-- $PostgreSQL: pgsql/doc/src/sgml/maintenance.sgml,v 1.77 2007/07/23 17:22:00 alvherre Exp $ --> |
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<chapter id="maintenance"> |
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<title>Routine Database Maintenance Tasks</title> |
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@ -496,16 +496,16 @@ HINT: Stop the postmaster and use a standalone backend to VACUUM in "mydb". |
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</para> |
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<para> |
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There is a limit of <xref linkend="guc-autovacuum-max-workers"> worker |
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processes that may be running at any time, so if the <command>VACUUM</> |
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and <command>ANALYZE</> work to do takes too long to run, the deadline may |
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be failed to meet for other databases. Also, if a particular database |
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takes a long time to process, more than one worker may be processing it |
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simultaneously. The workers are smart enough to avoid repeating work that |
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other workers have done, so this is normally not a problem. Note that the |
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number of running workers does not count towards the <xref |
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linkend="guc-max-connections"> nor the <xref |
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linkend="guc-superuser-reserved-connections"> limits. |
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The <xref linkend="guc-autovacuum-max-workers"> setting limits how many |
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workers may be running at any time. If several large tables all become |
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eligible for vacuuming in a short amount of time, all autovacuum workers |
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may end up vacuuming those tables for a very long time. This would result |
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in other tables and databases not being vacuumed until a worker became |
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available. There is also not a limit on how many workers might be in a |
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single database, but workers do try and avoid repeating work that has |
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already been done by other workers. Note that the number of running |
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workers does not count towards the <xref linkend="guc-max-connections"> nor |
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the <xref linkend="guc-superuser-reserved-connections"> limits. |
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</para> |
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<para> |
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