>> > 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.
>Probably won't change then. The boss was worried that a 16 Mb file size would
>cause performance issues on a busy database server.
>I would be more concerned about encountering performance problems by changing
>to
>a non-standard setting for something like wal segment size. I'd also want to
>do
>so very intensive performance testing of such a change before deploying it.
>Be
>very aware that just because something works in one fashion on another
>database
>like Oracle, it does not mean that it will work in the same fashion for
>Postgres
>(or any other DB for that matter).
>
>Brad.
We've decided against making any changes
