Re: explanation of some configs

On Tue, 10 Feb 2009, justin wrote:

> http://www.varlena.com/GeneralBits/Tidbits/annotated_conf_e.html
> checkpoint_segments
> Maximum distance between automatic WAL checkpoints, in log file segments (each
> segment is normally 16 megabytes).
>
> Increase these settings if your database has lots of large batch writes to
> decrease the frequency of checkpoints (and thus lower disk activity). Decrease
> them if you are short on disk space or your environment has a significant risk
> of unexpected power-outs, as any un-checkpointed transactions will dropped on
> restart.

You mentioned getting to there via
http://wiki.postgresql.org/wiki/Performance_Optimization

You'll note that link is disclaimed with "older version of material
covered in the GUC tour", and it's aimed at PostgreSQL 7.4. If you read
the current version of that document at
http://www.pgcon.org/2008/schedule/attachments/44_annotated_gucs_draft1.pdf
you'll see that text you've noted is incorrect isn't there anymore.

--
* Greg Smith gsmith(at)gregsmith(dot)com http://www.gregsmith.com Baltimore, MD