On Tue, Nov 28, 2006 at 12:08:59PM -0500, Tom Lane wrote:
> Peter Eisentraut <peter_e(at)gmx(dot)net> writes:
> > Aside from that my pgbench testing clearly shows that block sizes larger
> > than 2048 become progressively slower. Go figure.
>
> I believe that pgbench only stresses the "small writes" case, so
> perhaps this result isn't too surprising. You'd want to look at a mix
> of small and bulk updates before drawing any final conclusions.
>
> regards, tom lane
>
It has certainly been the case in every benchmark that I have ever seen
from RAID controllers to filesystem layouts that the sweet spot in the
trade-offs between small and large blocksizes was 8k. Other reasons
such as the need to cover a very large filespace of support many small
<< 1024 byte files, could tip the scales towards larger or smaller
blocksizes.
Ken