On Fri, 14 Nov 2003 11:00:38 -0500, "Nick Fankhauser" <[EMAIL PROTECTED]> wrote: >Good question... I've never used clustering in PostgreSQL before, so I'm >unsure. I presume this is like clustering in Oracle where the table is >ordered to match the index?
Yes, something like that. With the exception that Postgres looses the clustered status, while you INSERT and UPDATE tuples. So you have to re-CLUSTER from time to time. Look at pg_stats.correlation to see, if its necessary. > Is there a way to flush out >the cache in a testing situation like this in order to start from a >consistent base? To flush Postgres shared buffers: SELECT count(*) FROM another_large_table; To flush your database pages from the OS cache: tar cf /dev/null /some/large/directory And run each of your tests at least twice to get a feeling how caching affects your specific queries. Servus Manfred ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])