Re: Bumping block size to 16K on FreeBSD...

Sean, can we get a copy of your test set? And any scripts that you have
for running the tests?

On Thu, 28 Aug 2003, Tom Lane wrote:

> Sean Chittenden <sean(at)chittenden(dot)org> writes:
> > Early performance tests on my laptop suggest it's about 8% faster for
> > writing when both the FS and PostgreSQL use 16K blocks.
>
> BTW, I don't really believe that one set of tests, conducted on one
> single machine, are anywhere near enough justification for changing this
> value. Especially not if it's a laptop rather than a typical server
> configuration. You've got considerably less I/O bandwidth in proportion
> to CPU horsepower than a server. Why is that an issue? Well, a larger
> block size will substantially increase our WAL overhead (because we tend
> to dump whole blocks into WAL at the slightest provocation) and on
> slower machines the CRC64 calculations involved in WAL entries are a
> significant cost. On a machine with less CPU and more disk horsepower
> than you tested, the tradeoffs could be a lot different.
>
> regards, tom lane
>
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