Am 02.11.2012 17:12, schrieb Petr Praus:
Your CPUs are indeed pretty oldschool. FSB based, IIRC, not NUMA. A process migration would be even more expensive there.
Well, that pinned your _client_ to the CPUs, not the server side session ;-)
You'd have to spot for the PID of the new "IDLE" server process and pin that using "taskset -p". Also, 01 and 02 are probably cores in the same package/socket. Try "lscpu" first and spot for "NUMA node*" lines at the bottom.
But anyway... let's try something else first:
This only confirms what we've seen before. As soon as your work_mem permits an in-memory sort of the intermediate result set (which at that point in time is where? In the SHM, or in the private memory of the backend? I can't tell, tbth), the sort takes longer than when it's using a temp file.
What if you reduce the shared_buffers to your original value and only increase/decrease the session's work_mem? Same behaviour?
Cheers,
--
Gunnar "Nick" Bluth
RHCE/SCLA
Mobil +49 172 8853339
Email: gunnar.bluth@pro-open.de
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