Re: Fwd: FreeBSD, PostgreSQL, semwait and sbwait! - Mailing list pgsql-performance

From Tom Lane
Subject Re: Fwd: FreeBSD, PostgreSQL, semwait and sbwait!
Date
Msg-id 7576.1080082840@sss.pgh.pa.us
Whole thread Raw
In response to Re: Fwd: FreeBSD, PostgreSQL, semwait and sbwait!  (Josh Berkus <josh@agliodbs.com>)
List pgsql-performance
Josh Berkus <josh@agliodbs.com> writes:
> Forget hyperthreading.   Look at their postgresql.conf settings.   8mb shared
> mem, 16mb sort mem per connection for 512 connections, default
> effective_cache_size.

They could well be going into swap hell due to the oversized sort_mem,
but that didn't quite seem to explain the reported behavior.  I'd want
to see vmstat or similar output to confirm whether the disks are busy,
though.  Amazing how many people forget that a database is normally
I/O-bound rather than CPU-bound.

            regards, tom lane

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