Re: GiST indexes and concurrency (tsearch2)

Oleg Bartunov schrieb:
> Marinos,
>
> what if you construct "apachebench & Co" free script and see if
> the issue still exists. There are could be many issues doesn't
> connected to postgresql and tsearch2.
>

Some more things I tried:
- data directory on ramdisk (tmpfs) - no effect
- database connections either over Unix domain sockets or TCP - no effect
- CLUSTER on gist index - approx. 20% faster queries, but CPU usage
still hovers around 25% (75% idle)
- preemptible kernel - no effect

This is really baffling me, it looks like a kernel issue of some sort
(I'm only guessing though). I found this old posting:
http://archives.postgresql.org/pgsql-general/2001-12/msg00836.php - is
this still applicable? I don't see an unusually high number of context
switches, but the processes seem to be spending some time in
"semtimedop" (even though the TAS assembly macros are definetely being
compiled-in).

If you are interested, I can probably provide an account on one of our
identically configured boxes by Monday afternoon (GMT+1) with the same
database and benchmarking utility.

Regards,
Marinos