Re: how to truncate/purge the pg_xlog directory?

tfinneid@student.matnat.uio.no wrote:
> Hi
>
> As far as I understand pg_xlog  is the transaction log i.e. the WAL.

Correct. And it should have files called e.g. 0000000100000005000000E9
each 16MB long.

> I have a pg 8.2 which has consumed about 113MB in pg_xlog/, while the
> cluster is virtually empty.

OK, so that's 7 files?
What is your checkpoint_segments setting in postgresql.conf? If it's 3
then you can indeed expect a maximum of 7 WAL files. For a low-activity
system you can always turn the setting down.

 > There are a couple of tables in the postgres
> schema, but they contain no data at the moment. My disk is filling up and
> I want to purge directories that are larger than need to be.
> I performed a VACUUM FULL, because I thought that would help, but it did not.
> I searched the net and the forums here and found only one post about
> tuning the wal parameters to control the pg_xlog directory size, but when
> looking at the documentation for that I found nothing that could be used
> for that
>
> Also the base/ directory is 268MB big and still not many tables, is ti
> possible to purge that directory as well?.

You might find the "pg_xxx_size()" functions useful - they are detailed
in the functions/system-admin chapter of the manuals.

--
   Richard Huxton
   Archonet Ltd