On 25 March 2012 09:17, Simon Riggs <simon@2ndquadrant.com> wrote:
> The main thing we're waiting on are the performance tests to confirm
> the lack of regression.
I have extensively benchmarked the latest revision of the patch
(tpc-b.sql), which I pulled from Alvaro's github account. The
benchmark was of the feature branch's then-and-current HEAD, "Don't
follow update chains unless caller requests it".
I've had to split these numbers out into two separate reports.
Incidentally, at some future point I hope that pgbench-tools can
handling testing across feature branches, initdb'ing and suchlike
automatically and as needed. That's something that's likely to happen
sooner rather than later.
The server used was kindly supplied by the University of Oregon open
source lab.
Server (It's virtualised, but apparently this is purely for sandboxing
purposes and the virtualisation technology is rather good):
IBM,8231-E2B POWER7 processor (8 cores).
Fedora 16
8GB Ram
Dedicated RAID1 disks. Exact configuration unknown.
postgresql.conf (this information is available when you drill down
into each test too, fwiw):
max_connections = 200
shared_buffers = 2GB
checkpoint_segments = 30
checkpoint_completion_target = 0.8
effective_cache_size = 6GB
Reports:
http://results_fklocks.staticloud.com/
http://results_master_for_fks.staticloud.com/
Executive summary: There is a clear regression of less than 10%. There
also appears to be a new source of contention at higher client counts.
I realise that the likely upshot of this, and other concerns that are
generally held at this late stage is that this patch will not make it
into 9.2 . For what it's worth, that comes as a big disappointment to
me. I would like to thank both Alvaro and Noah for their hard work
here.
--
Peter Geoghegan http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training and Services
