Re: SMP Read-only Performance

Mike Bresnahan wrote:
> As you see, the TPS remains the same as I increase the number of clients. These
> results make it look like PostgreSQL is single-threaded and not taking advantage
> of the multiple cores. Could someone please explain?
>

You're probably running into this problem:
http://notemagnet.blogspot.com/2008/05/pgbench-suffering-with-linux-2623-2626.html

I discovered that the issue with pgbench not running well on recent
Linux kernels only occurs if you're connecting over the default sockets
interface. If you setup your server to listen over TCP/IP instead (may
have to tweak pg_hba.conf and listen_address in the postgresql.conf
file), so that you can connect to it like this successfully:

psql -h localhost

You can then use the same method on pgbench:

pgbench -c 1 -S -t 400000 test -h localhost

And I'd bet that you'd then see the scaling you expect.

--
Greg Smith 2ndQuadrant Baltimore, MD
PostgreSQL Training, Services and Support
greg(at)2ndQuadrant(dot)com www.2ndQuadrant.com