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Re: auto vacuum, not working? - Mailing list pgsql-performance

From Greg Smith
Subject Re: auto vacuum, not working?
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Msg-id 4F12C20E.7080400@2ndQuadrant.com
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In response to auto vacuum, not working?  ("Anibal David Acosta" <aa@devshock.com>)
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On 01/13/2012 07:08 AM, Anibal David Acosta wrote:

How can I release the space used by deleted rows? Without block the table.


The database can only reduce the size tables by returning space to the operating system in one situation:  there is free space at the very end of the table.  In that case, if it's possible to get a brief exclusive lock on the table, it can shrink in size.

There are some programs available that reorganize table for goals like this, without having any long-lasting locks on the tables.  pg_reorg is the most popular example:  http://pgfoundry.org/projects/reorg/

-- 
Greg Smith   2ndQuadrant US    greg@2ndQuadrant.com   Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.com

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