On Mon, 26 Mar 2007, ITAGAKI Takahiro wrote:

I'm assuming checkpoints are triggered by timeout in normal use -- and it's my recommended configuration whether the patch is installed or not.


I'm curious what other people running fairly serious hardware do in this area for write-heavy loads, whether it's timeout or segment limits that normally trigger their checkpoints.

I'm testing on a slightly different class of machine than your sample results, something that is in the 1500 TPS range running the pgbench test you describe. Running that test, I always hit the checkpoint_segments wall well before any reasonable timeout. With 64 segments, I get a checkpoint every two minutes or so.

There's something I'm working on this week that may help out other people trying to test your patch out. I've put together some simple scripts that graph (patched) pgbench results, which make it very easy to see what changes when you alter the checkpoint behavior. Edges are still rough but the scripts work for me, will be polishing and testing over the next few days:

http://www.westnet.com/~gsmith/content/postgresql/pgbench.htm

(Note that the example graphs there aren't from the production system I mentioned above, they're from my server at home, which is similar to the system your results came from).

--
* Greg Smith [EMAIL PROTECTED] http://www.gregsmith.com Baltimore, MD

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