with Postgresql 7.2.1 you will need to do BOTH vacuum and reindex and with a table that gets many updates/deletes, you should run vacuum more than daily. Both issues have been solved in 8.1. Jim ---------- Original Message ----------- From: Emmanuel Lacour <elacour@xxxxxxxxxxxxxxx> To: pgsql-performance@xxxxxxxxxxxxxx Sent: Mon, 30 Jan 2006 23:57:11 +0100 Subject: [PERFORM] Query planner issue > Hi everybody, > > I have the following problem, on a test server, if I do a fresh import > of production data then run > 'explain analyze select count(*) from mandats;' > > I get this result: > > Aggregate (cost=6487.32..6487.32 rows=1 width=0) (actual time=607.61..607.61 rows=1 loops=1) > -> Seq Scan on mandats (cost=0.00..6373.26 rows=45626 width=0) (actual time=0.14..496.20 rows=45626 > loops=1) Total runtime: 607.95 msec > > On the production server, if I do the same (without other use of the server), I get: > > Aggregate (cost=227554.33..227554.33 rows=1 width=0) (actual time=230705.79..230705.79 rows=1 loops=1) > -> Seq Scan on mandats (cost=0.00..227440.26 rows=45626 width=0) (actual time=0.03..230616.64 rows=45760 > loops=1) Total runtime: 230706.08 msec > > Is there anyone having an idea on how yo solve this poor performances? I > think it is caused by many delete/insert on this table every day, but > how to solve it, I need to run this qury each hour :(. I run > vacuum each night, postgresql is unfortunatly 7.2.1 :( (no upgrade > before 2 or 3 months). > > -- > Emmanuel Lacour ------------------------------------ Easter-eggs > 44-46 rue de l'Ouest - 75014 Paris - France - Métro Gaité > Phone: +33 (0) 1 43 35 00 37 - Fax: +33 (0) 1 41 35 00 76 > mailto:elacour@xxxxxxxxxxxxxxx - http://www.easter-eggs.com > > ---------------------------(end of broadcast)--------------------------- > TIP 6: explain analyze is your friend ------- End of Original Message -------
