On Mon, Feb 13, 2012 at 7:45 AM, Robert Haas <robertmh...@gmail.com> wrote: > On Thu, Feb 9, 2012 at 3:37 PM, Jay Levitt <jay.lev...@gmail.com> wrote: >> So my pre-built 9.1.2 takes 434s, my source-built 9.2 takes 509s, and >> (probably both of our) 9.1-HEAD takes 1918s... is that something to worry >> about, and if so, are there any tests I can run to assist? That bug doesn't >> affect me personally, but y'know, community and all that. Also, I wonder if >> it's something like "9.2 got way faster doing X, but meanwhile, HEAD got way >> slower doing Y.", and this is a canary in the coal mine. > > This might be a lame hypothesis, but... is it possible that you built > your 9.1-tip binaries with --enable-cassert? Or with different > optimization options? > > There's been some work done on GiST in 9.2, which as Alexander > Korotkov who did the work mentioned upthread, might have some issue. > But I can't see how there can be a 4x regression between minor > releases, though maybe it wouldn't hurt to test.
So I tested. On my MacBook Pro, your test script builds the index in just over 25 s on both REL9_1_2 and this morning's REL9_1_STABLE. This is with the following non-default configuration settings: shared_buffers = 400MB maintenance_work_mem = 1GB checkpoint_segments = 30 checkpoint_timeout = 10min checkpoint_completion_target = 0.9 checkpoint_warning = 60s I then tested with master, which also showed similar performance. Based on this comment from your original email: >> [***] never completed after 10-20 minutes; nothing in server.log at default >> logging levels, postgres process consuming about 1 CPU in IOWAIT, >> checkpoints every 7-8 seconds ...I wonder if you have left checkpoint_segments set to the default value of 3, which would account for the very frequent checkpoints. At any rate, I can't measure a difference between the branches on this test. That doesn't mean there isn't one, but in my test setup I'm not seeing it. As an afterthought, I also retested with wal_level=archive added to the config, but I still don't see any significant difference between 9.1.2, 9.1-stable, and 9.2-devel. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
