Re: automated index suggestor -- request for comment
От | Ron Johnson |
---|---|
Тема | Re: automated index suggestor -- request for comment |
Дата | |
Msg-id | 1039895176.16976.26.camel@haggis обсуждение исходный текст |
Ответ на | automated index suggestor -- request for comment (johnnnnnn <john@phaedrusdeinus.org>) |
Список | pgsql-performance |
On Thu, 2002-12-12 at 21:22, johnnnnnn wrote: > The manual is pretty sparse on advice regarding indices. Plenty of > good feature documentation, but not much about when and where an index > is appropriate (except a suggestion that multi-column indices should > be avoided). > > Of course, the ultimate arbiter of which indices are used is the > planner/optimizer. If i could somehow convince the optimizer to > consider indices that don't yet exist, it could tell me which would > give the greatest benefit should i add them. > > So, i'm writing for two reasons. First, i want to gauge interest in > this tool. Is this something that people would find useful? > > Second, i am looking to solicit some advice. Is this project even > feasible? If so, where would be the best place to start? My assumption > has been that i would need to hack into the current code for > determining index paths, and spoof it somehow, but is that possible > without actually creating the indices? Isn't this what a DBA (or, heck, even a modestly bright developer) does during transactional analysis? You know what the INSERTs and statements-that-have-WHERE-clauses are, and, hopefully, approximately how often per day (or week) each should execute. Then, *you* make the decision about which single-key and multi-key indexes should be created, based upon a) the cardinality of each table b) the frequency each query (includes UPDATE & DELETE) is run c) how often INSERT statements occur Thus, for example, an OLTP database will have a significantly different mix of indexes than, say, a "reporting" database... -- +---------------------------------------------------------------+ | Ron Johnson, Jr. mailto:ron.l.johnson@cox.net | | Jefferson, LA USA http://members.cox.net/ron.l.johnson | | | | "My advice to you is to get married: If you find a good wife, | | you will be happy; if not, you will become a philosopher." | | Socrates | +---------------------------------------------------------------+
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