Re: How do you change the size of the WAL files?

On Fri, 2011-03-11 at 12:51 -0500, Bruce Momjian wrote:
> runner wrote:
> >
> >
> >
> > Our WAL files are 16 Mb in size each. I cannot find where you
> > configure them to make them larger. 16 Mb is too small for our
> > instalation. If necessary, I can rebuild the entire cluster. Our
> > DBA initialized a new cluster and specified a larger WAL size but it
> > stayed at 16 Mb. Any info on this?
>
> Why is 16MB too small? Most people increase checkpoint_segments for
> larger installs and it works fine.

To answer the question, it is possible to change the wal log size. It is
a setting in pg_config.h: #define XLOG_SEG_SIZE (16 * 1024 * 1024) .

If you change that and recompile, your wal segment size will be
different. I have heard of people running 32meg sizes. We have tried
with smaller sizes but it ended up thrashes the disk.

Further keep in mind you will have to do a dump and restore to the new
cluster. Your existing cluster will not be usable once you do this.

Joshua D. Drake

>
> --
> Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
> EnterpriseDB http://enterprisedb.com
>
> + It's impossible for everything to be true. +
>

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