Scott Carey wrote:
But the select count(*) query, cached in RAM is 3x faster in one system than
the other. The CPUs aren't 3x different performance wise. Something else may
be wrong here.
An individual Core2 Duo 2.93Ghz should be at most 50% faster than a 2.2Ghz
Opteron for such a query. Unless there are some compile options that are set
wrong. I would check the compile options.
Sure, it might be. But I've seen RAM on an Intel chip like the E7500
here (DDR3-1066 or better, around 10GB/s possible) run almost 3X as fast
as what you'll find paired with an Opteron 2427 (DDR2-800, closer to
3.5GB/s). Throw in the clock differences and there you go.
I've been wandering around for years warning that the older Opterons on
DDR2 running a single PostgreSQL process are dog slow compared to the
same thing on Intel. So that alone might actually be enough to account
for the difference. Ultimately the multi-processor stuff is what's more
important to most apps, though, which is why I was hinting to properly
run that instead.
--
Greg Smith 2ndQuadrant US Baltimore, MD
PostgreSQL Training, Services and Support
g...@2ndquadrant.com www.2ndQuadrant.us
--
Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-performance
