Centuries ago, Nostradamus foresaw when [EMAIL PROTECTED] (Javier Somoza) would write: > Hi all > I've a question about vacuuming, ... > Vacuum: cleans out obsolete and deleted registers... > Analyze: update statistics for the planner > Reindex: rebuild indexes > I think the correct order to perform the database maintenance for > performance is: > 1 - Vacuum > 2 - Reindex > 3 - Analyze > So the planner is updated with the updated indexes.
There is a misunderstanding there. The planner isn't aware of "updates" to the indexes; it is aware of how they are defined. ANALYZE doesn't calculate index-specific things; it calculates statistical distributions for the contents of each column. As soon as it runs, the planner will be better able to choose from the available indexes. If you add another index, the planner will, without another ANALYZE, be able to choose that index, if it is useful to do so, based on the existing statistical distributions. > The autovacuum daemon does vacuum and analyze. Not reindex. > So, no way to perform it in that order. > What do you think? > How often do you reindex your tables? If tables are being vacuumed frequently enough, the answer to that can be "almost never." Back in the days of 7.2, there were conditions where indexes could bloat mercilessly, so that heavily updated tables needed a reindex every so often. But if you're running a reasonably modern version, that shouldn't be necessary. -- wm(X,Y):-write(X),write('@'),write(Y). wm('cbbrowne','gmail.com'). http://linuxfinances.info/info/slony.html Rules of the Evil Overlord #219. "I will be selective in the hiring of assassins. Anyone who attempts to strike down the hero the first instant his back is turned will not even be considered for the job." <http://www.eviloverlord.com/> ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster