On Wed, 2009-07-22 at 22:23 -0400, Greg Smith wrote: > Onto performance. My test system has a 16 cores of Xeon X5550 @ > 2.67GHz. > I created a little pgbench database (-s 10) and used the default > postgresql.conf parameters for everything but max_connections for a > rough > initial test.
To test on Windows, I set up a similar database on an 8-core 2.0GHz E5335 (closest match I have.) It's compiled against a fresh CVS pull from this morning, patched with the "20090724" updated version. I tried to mirror the tests as much as possible, including the concurrent thread counts despite having half the number of available cores. Doing that didn't have much impact on the results, but more on that later. Comparing the unpatched version to the new version running a single client thread, there's no significant performance difference: C:\pgsql85>bin\pgbenchorig.exe -S -c 8 -t 100000 pgbench ... tps = 19061.234215 (including connections establishing) C:\pgsql85>bin\pgbench.exe -S -c 8 -t 100000 pgbench tps = 18852.928562 (including connections establishing) As a basis of comparison the original pgbench was run with increasing client counts, which shows the same drop off in throughput past the 16-client sweet spot: con tps 8 18871 16 19161 24 18804 32 18670 64 17598 128 16664 However I was surprised to see these results for the patched version, running 16 worker threads (apart from the 8 client run of course.) C:\pgsql85>bin\pgbench.exe -S -j 16 -c 128 -t 100000 pgbench ... con tps 8 18435 (-j 8) 16 18866 24 ----- 32 17937 64 17016 128 15930 In all cases the patched version resulted in a lower performing output than the unpatched version. It's clearly working, at least in that it's launching the requested number of worker threads when looking at the process. Adjusting the worker thread count down to match the number of cores yielded identical results in the couple of test cases I ran. Maybe pgbench itself is less of a bottleneck in this environment, relatively speaking? - Josh Williams -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
