On Mon, Nov 27, 2006 at 04:47:57PM -0500, Tom Lane wrote:
> It seems at least as likely that increased block size would *decrease*
> performance by requiring even small writes to do more physical I/O.
> This applies to both data files and xlog.
FWIW, a test we performed on just this some time ago was
inconclusive, and I chalked up the inconclusiveness to exactly the
increase in physical I/O for small writes. I couldn't release the
results, just because I wasn't in a position to release the test
data, but we had a fairly eclectic mixture of big and small rows. On
certain workloads, it was in fact slower than the stock size (IIRC we
tried both 16k and 32k), which is what led me to that speculation.
But I never chased any of it down, because the preliminary results
were so unpromising.
A
--
Andrew Sullivan | ajs@crankycanuck.ca
I remember when computers were frustrating because they *did* exactly what
you told them to. That actually seems sort of quaint now. --J.D. Baldwin