Jeff <[EMAIL PROTECTED]> wrote: > Then run "VACUUM ANALYZE" every once in a while (depending on how > fast your data changes), like every night for instance.
Consider VACUUM and ANALYZE somewhat separately. You need to ANALYZE any time the distribution of the data changes. You need to VACUUM any time a lot of data is invalidated by UPDATEs or DELETEs. (And when you VACUUM, it's cheap to throw in an ANALYZE.) That turns into a variety of policies depending on what the pattern of activity for a particular table is: - If a table only ever gets INSERTs, you need only ever ANALYZE it, as VACUUM should be useless. (Caveat: If INSERTs could get rolled back due to other processing nuking transactions, that leaves dead tuples for VACUUM to work with...) - A table that sees enormous numbers of updates (for instance, a list of account balances) should be vacuumed REALLY frequently. - Any time you do a VACUUM, you might as well also do an ANALYZE. pg_autovacuum applies these policies, so it's a reasonable thing to use in 7.3/7.4... -- If this was helpful, <http://svcs.affero.net/rm.php?r=cbbrowne> rate me http://www3.sympatico.ca/cbbrowne/ "One of the most dangerous things in the universe is an ignorant people with real grievances. That is nowhere near as dangerous, however, as an informed and intelligent society with grievances. The damage that vengeful intelligence can wreak, you cannot even imagine." -- Miles Teg, Heretics of Dune ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
