Tom Lane wrote:
>Attached is a modification that prevents additional waiters from being
>released until the first releasee has a chance to run and acquire the
>lock. Would you try this and see if it's better or not in your test
>cases? It doesn't seem to help on a single CPU, but maybe on multiple
>CPUs it'll make a difference.
>
Here are some results for Linux 2.2 on a Dual PentiumPro 200MHz, SCSI
disks and way too litte RAM
(just 128MB). I observed the loadavg. with the three different 7.2
versions and 50 clients, without patch
the load stayed low (2-3), with patch no1 very high (12-14) and with
patch no2 between the two others
(6-8). Any of the patches seem to be a big win with the second version
being slightly better. I could run
benchmarks on 7.1 if that would be interesting. I used the same
benchmark database with a
VACUUM FULL between each version of the backend tested. I also re-run
some of the tests on the same
database after I tested all loads on the different versions, and numbers
stayed very simmilar (difference:
0.1-0.3 tps).
Best regrds
Fredrik Estreen