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

From Kevin Grittner
Subject Re: auto vacuum, not working?
Date
Msg-id 4F0FF04D0200002500044778@gw.wicourts.gov
Whole thread Raw
In response to Re: auto vacuum, not working?  (Mario Weilguni <roadrunner6@gmx.at>)
List pgsql-performance
Mario Weilguni <roadrunner6@gmx.at> wrote:

>> yesterday I delete about 200 million rows of a table

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

> vacuum does not reclaim space, just marks tuples dead. You need
> vacuum full.

VACUUM FULL will lock the table, blocking all other access, and it
can run for quite a while.  If you expect to be adding 200 million
new rows to the table in the foreseeable future, a regular VACUUM
(or autovacuum) will make that space available for reuse by that
table.  The space won't show in the file system; it will still be
allocated to the database but available for new rows.

-Kevin

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