Re: Where to configure pg_xlog file-size?

Clemens Eisserer wrote on 12.04.2010 23:25:
> Hi,
>
> I am using postgres-8.3 on an embedded ARM9 system.
> Works pretty well, except for stoarge consumptions.
>
> The actual table data is rather small, but postgres creates 2 16mb
> files in pg_xlog:
> root@mesrv:/var/lib/postgresql/8.3/main# ls -la pg_xlog/
> total 32820
> -rw-------  1 postgres postgres 16777216 2010-04-12 15:00
> 000000010000000000000006
> -rw-------  1 postgres postgres 16777216 2010-04-11 23:42
> 000000010000000000000007
>
> Is there anything I can do to lower the size of those two files?
> What are reasonable values for smaller databases, and if it can be
> changed, what impact would it have on the system?
>
> Thanks, Clemens
>

Those are checkpoint segments.

I don't think you change the size of the files, but you should be able to limit that to one file.

http://www.postgresql.org/docs/8.3/static/runtime-config-wal.html#RUNTIME-CONFIG-WAL-CHECKPOINTS

Although I have no idea about the impact regarding performance. But I guess if you don't have too many writes it might
actuallybe OK. 

Thomas