> -----Original Message----- > From: Joel Fradkin [mailto:[EMAIL PROTECTED] > Sent: Thursday, April 14, 2005 11:39 AM > To: 'Tom Lane'; 'Dawid Kuroczko' > Cc: 'PERFORM' > Subject: Re: [PERFORM] speed of querry? > > > I did as described to alter table and did not see any > difference in speed. I am trying to undo the symbolic > link to the data array and set it up on raid 5 disks in > the machine just to test if there is an issue with the > config of the raid 10 array or a problem with the controller. > > I am kinda lame at Linux so not sure I have got it yet still > testing. Still kind puzzled why it chose tow different option, > but one is running windows version of postgres, so maybe that > has something to do with it.
That sounds like a plausible explanation. However, it could simply be that the statistics gathered on each box are sufficiently different to cause different plans. > The data bases and configs (as far as page cost) are the same. Did you do as Dawid suggested? > [...] > Then do a query couple of times (EXPLAIN ANALYZE also :)), then > do: > SET enable_seqscan = off; > and rerun the query -- if it was significantly faster, you will > want to do: > SET enable_seqscan = on; > and tweak: > SET random_page_cost = 2.1; > ...and play with values. When you reach the random_page_cost > which suits your data, you will want to put it into > postgresql.conf > [...] This is above and beyond toying with the column statistics. You are basically telling the planner to use an index. Try this, and post the EXPLAIN ANALYZE for the seqscan = off case on the slow box if it doesn't speed things up for you. __ David B. Held Software Engineer/Array Services Group 200 14th Ave. East, Sartell, MN 56377 320.534.3637 320.253.7800 800.752.8129 ---------------------------(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