On Mar 5, 2007, at 8:34 PM, Greg Smith wrote:
On Thu, 22 Feb 2007, Jim C. Nasby wrote:

It would also be extremely useful to make checkpoint stats visible somewhere in the database (presumably via the existing stats mechanism)... I'm thinking just tracking how many pages had to be flushed during a checkpoint would be a good start.

I'm in the middle of testing an updated version of the patch, once I nail down exactly what needs to be logged I'd planned to open a discussion on which of those things would be best served by pg_stats instead of a log.

I decided specifically to aim for the logs instead for the checkpoint data because if you're in a situation where are inserting fast enough that the checkpoints are spaced closely together, you'd end up having to poll pg_stats all the time for make sure you catch them all, which becomes even less efficient than just logging the data.

It's always good to be able to log stuff for detailed troubleshooting, so that's a good place to start. The flipside is that it's much easier to machine-parse a table rather than trying to scrape the logs. And I don't think we'll generally care about each individual checkpoint; rather we'll want to look at things like 'checkpoints/hour' and 'checkpoint written pages/hour'.
--
Jim Nasby                                            [EMAIL PROTECTED]
EnterpriseDB      http://enterprisedb.com      512.569.9461 (cell)



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