Re: Scaling concerns

[Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>]

tsuraan <tsuraan(at)gmail(dot)com> writes:
> Is the WAL at the same location as the xlog (transaction log?)?

Same thing.

> The checkpoint_segments doc says increasing that value is really only
> useful if the xlog is separate from the data,

Dunno where you read that, but it's utter bilge.  If you've got a
write-intensive workload, you want to crank checkpoint_segments as high
as you can stand.  With the default settings on a modern machine it's
not hard at all to push it into checkpointing every dozen or seconds,
which will completely kill performance.  (Disk space for pg_xlog/ and
potential delay during crash restart are the only negatives here.  If
you are willing to push the average inter-checkpoint interval past five
minutes then you need to increase checkpoint_timeout too.)

			regards, tom lane