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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