Re: TRUNCATE - timing of the return of disk space - caused by long-lived client? - Mailing list pgsql-general

From Alvaro Herrera
Subject Re: TRUNCATE - timing of the return of disk space - caused by long-lived client?
Date
Msg-id 20071026120526.GA5968@alvh.no-ip.org
Whole thread Raw
In response to TRUNCATE - timing of the return of disk space - caused by long-lived client?  ("Vince Negri" <vnegri@asl-electronics.co.uk>)
List pgsql-general
Vince Negri wrote:

> So I tried TRUNCATE on the table. It appeared to work  - in that the
> row count dropped to zero and the connected client was not disrupted,
> and "du" on the postgres data directory showed a fall.
>
> But the available disk space (reported by "df") did not fall.

I think you shouldn't worry about it.  The file will eventually be
closed (maybe after a couple of checkpoints) and the space returned to
the filesystem.

FYI what TRUNCATE does is create a new, separate file for the table and
index storages.  The old one can still be open for a while, but it
should get detached not long after the transaction commits.

--
Alvaro Herrera                                http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support

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