Re: GiST indexes and concurrency (tsearch2) - Mailing list pgsql-performance

From Marinos J. Yannikos
Subject Re: GiST indexes and concurrency (tsearch2)
Date
Msg-id 420AB0E9.8070808@geizhals.at
Whole thread Raw
In response to Re: GiST indexes and concurrency (tsearch2)  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-performance
Tom Lane wrote:
> I'm not completely convinced that you're seeing the same thing,
> but if you're seeing a whole lot of semops then it could well be.

I'm seeing ~280 semops/second with spinlocks enabled and ~80k
semops/second (> 4 mil. for 100 queries) with --disable-spinlocks, which
increases total run time by ~20% only. In both cases, cpu usage stays
around 25%, which is a bit odd.

> [...]You said
> you're testing a quad-processor machine, so it could be that you're
> seeing the same lock contention issues that we've been trying to figure
> out for the past year ...

Are those issues specific to a particular platform (only x86/Linux?) or
is it a problem with SMP systems in general? I guess I'll be following
the current discussion on -hackers closely...

Regards,
  Marinos

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