Re: [PERFORM] PG writes a lot to the disk

2008-03-20 Thread Laurent Raufaste
2008/3/19, Laurent Raufaste [EMAIL PROTECTED]: What does it writes so much in the base directory ? If it's some temporary table or anything, how can I locate it so I can fix the problem ? Thanks for your help everybody ! I fixed the problem by doing an ANALYZE to every table (yes I'm so

Re: [PERFORM] PG writes a lot to the disk

2008-03-20 Thread Albe Laurenz
Laurent Raufaste wrote: The problem was that the optimiser didn't know how to run the queries well and used millions of tuples for simple queries. For each tuple used it was updating some bit in the table file, resulting in a huge writing activity to that file. Good that you solved your

Re: [PERFORM] PG writes a lot to the disk

2008-03-20 Thread Bill Moran
In response to Albe Laurenz [EMAIL PROTECTED]: Laurent Raufaste wrote: The problem was that the optimiser didn't know how to run the queries well and used millions of tuples for simple queries. For each tuple used it was updating some bit in the table file, resulting in a huge writing

Re: [PERFORM] PG writes a lot to the disk

2008-03-20 Thread Tom Lane
Bill Moran [EMAIL PROTECTED] writes: However, the part I wanted to comment on (and got busy yesterday so am only getting to it now) is that there's no guarantee that SELECT isn't modifying rows. Another way that SELECT can cause disk writes is if it sets hint bits on recently-committed rows.

Re: [PERFORM] PG writes a lot to the disk

2008-03-20 Thread Kris Jurka
On Thu, 20 Mar 2008, Albe Laurenz wrote: PostgreSQL doesn't write into the table files when it SELECTs data. It could easily be hint bit updates that are set by selects getting written. Kris Jurka -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make

Re: [PERFORM] PostgreSQL NetApp and NFS

2008-03-20 Thread Bruce Momjian
Chris Hoover wrote: If you have any real life good or bad stories, I'd love to hear it. Given the NetApp arrays supposedly being very good NFS platforms, overall, is this a recommended way to run PostgreSQL, or is it recommended to not run this way. We do have an NFS section in our

Re: [PERFORM] PostgreSQL NetApp and NFS

2008-03-20 Thread Woody Woodring
I need to know if anyone out there is/has run their PostgreSQL on NetApp arrays via NFS. My particular situation is RH Linux 4 servers running Postgresql 8.1. I need to provide our Operations manager with specific reasons why we should not run PostgreSQL over NetApp NFS. Otherwise, they

Re: [PERFORM] PostgreSQL NetApp and NFS

2008-03-20 Thread Frits Hoogland
My experience postgresql work good on NFS. Of course, use NFS over TCP, and use noac if you want to protect your database even more (my experience is NFS client caching doesn't lead to an irrecoverable database however) I've encountered problems with RHEL4 as a database server and a client of a

Re: [PERFORM] PostgreSQL NetApp and NFS

2008-03-20 Thread Tom Lane
Bruce Momjian [EMAIL PROTECTED] writes: Chris Hoover wrote: If you have any real life good or bad stories, I'd love to hear it. Given the NetApp arrays supposedly being very good NFS platforms, overall, is this a recommended way to run PostgreSQL, or is it recommended to not run this way.

Re: [PERFORM] PostgreSQL NetApp and NFS

2008-03-20 Thread Bruce Momjian
Tom Lane wrote: Bruce Momjian [EMAIL PROTECTED] writes: Chris Hoover wrote: If you have any real life good or bad stories, I'd love to hear it. Given the NetApp arrays supposedly being very good NFS platforms, overall, is this a recommended way to run PostgreSQL, or is it recommended

Re: [PERFORM] PostgreSQL NetApp and NFS

2008-03-20 Thread Tom Lane
Bruce Momjian [EMAIL PROTECTED] writes: Tom Lane wrote: Aside from what's said there, I'd note that it's a seriously bad idea to use a soft mount or any arrangement wherein it's possible for Postgres to be running while the NFS disk is not mounted. Do the docs need updating for this?