Re: Solaris and effective_cache_size

Andrew Sullivan <andrew@libertyrms.info> writes:
> Solaris is _much_ more aggressive about disk caching than Linux is,
> it seems.  I suspected that adjusting the effective_cache_size
> setting might therefore help.

> Using pgbench, I discovered a performance advantage of almost 10% by
> increasing the setting from the default 1000 to 1500.  I am not sure
> whether this figure will hold up, but it was consistent over multiple
> tests.

Actually, the default 1000 setting is probably very much on the low side
--- that's only equivalent to 8 meg of disk cache space after all, and
on any reasonably modern box there's probably lots more RAM than that
being used for disk cache.

However, I'm quite surprised to hear that tweaking effective_cache_size
affects pgbench results at all.  I'd have thought that all the queries
used by pgbench would be indexscans anyway...

            regards, tom lane