Re: XLOG_BLCKSZ vs. wal_buffers table

On Tue, May 02, 2006 at 05:00:58PM +0200, Zeugswetter Andreas DCP SD wrote:
> 
> > I'm planning on continuing to increase XLOG_BLCKSZ and wal_buffers to
> > determine when the throughput starts to level out or drop 
> 
> I think for an even better comparison you should scale wal_buffers
> down with increasing XLOG_BLCKSZ, so that the xlog buffer has a fixed
> size in kb.
> 
> Reasonable wal_buffers imho amount to at least 256kb, better yet 512 or
> 1 Mb,
> with sufficiently large transactions (and to try to factor out the
> difference 
> between blocksizes).

AFAIK all the transactions in DBT2 are pretty small. I think all DML is
single-row in fact, so I'm not sure that having wal_buffers much larger
than the number of connections would help much.
-- 
Jim C. Nasby, Sr. Engineering Consultant      jnasby@pervasive.com
Pervasive Software      http://pervasive.com    work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf       cell: 512-569-9461