Обсуждение: WAL disk space

An empty database cluster takes up 20 MB, 16 of which
are dedicated to a WAL file. This seems to be a lot
for a small or low-traffic database. Is there any way
to reduce the size of this WAL file, besides reverting
to version 7.0 (where WAL isn't used)?
Thanks -Erin

On Mon, 9 Dec 2002, Erin Munro wrote:

> An empty database cluster takes up 20 MB, 16 of which
> are dedicated to a WAL file. This seems to be a lot
> for a small or low-traffic database. Is there any way
> to reduce the size of this WAL file, besides reverting
> to version 7.0 (where WAL isn't used)?

IIRC, you can change the segment size at compile time in
xlog.h.

Erin Munro <emunro@ll.mit.edu> writes:
> An empty database cluster takes up 20 MB, 16 of which
> are dedicated to a WAL file. This seems to be a lot
> for a small or low-traffic database. Is there any way
> to reduce the size of this WAL file, besides reverting
> to version 7.0 (where WAL isn't used)?

Reduce XLogSegSize in src/include/access/xlog.h.  Recompile,
re-initdb (or at least do pg_resetxlog), put up with more frequent
checkpoints.

With sufficiently low write activity this might be worthwhile, but
I find it hard to think of any recently-manufactured hardware wherein
16MB of disk space is worth agonizing over.

            regards, tom lane