[PERFORM] NAS, SAN or any alternate solution ?

2004-07-20 Thread bsimon
Hi all, I've been searching the list for a while but couldn't find any up-to-date information relating to my problem. We have a production server with postgresql on cygwin that currently deels with about 200 Gigs of data (1 big IDE drive). We plan to move to linux for some reasons I don't have to

Re: [PERFORM] NAS, SAN or any alternate solution ?

2004-07-20 Thread Scott Marlowe
On Tue, 2004-07-20 at 01:52, [EMAIL PROTECTED] wrote: > Hi all, > > I've been searching the list for a while but couldn't find any > up-to-date information relating to my problem. > We have a production server with postgresql on cygwin that currently > deels with about 200 Gigs of data (1 big IDE

Réf. : Re: [PERFORM] NAS, SAN or any alternate solution ?

2004-07-20 Thread bsimon
Thanks a lot Scott. It seems that we were totally wrong when considering a network storage solution. I've read your techdoc http://techdocs.postgresql.org/guides/DiskTuningGuide and found many interesting remarks. I think that we will know focus on external Raid systems which seem to be relativi

Re: [PERFORM] Réf. : Re: [PERFORM] NAS,

2004-07-20 Thread Mark Kirkwood
[EMAIL PROTECTED] wrote: As we don't plan to have more than 5 connections (I.E process), we think SATA drives would fit our requirements. Could this be an issue for an after crash recovery ? If you can disable the write ATA write cache, then you have safety. Unfortunately many cards under Linu

Réf. : Re: Réf. : Re: [PERFORM] NAS, SAN or any alternate solution ?

2004-07-20 Thread bsimon
I must say that cygwin did well (there exists good software on windows, i've found one)... as a prototype ... when I look at the postgresql poll (http://www.postgresql.org/survey.php?View=1&SurveyID=11), it seems like I'm not alone !! Actually, the major problem was the limit of the available allo

Re: [PERFORM] Working on huge RAM based datasets

2004-07-20 Thread abhousehunt
Sorry for the late reply - I've been away, and I've had problems posting too :( Merlin, I'd like to come back with a few more points! >That's the whole point: memory is a limited resource. If pg is >crawling, then the problem is simple: you need more memory. My posting only relates to the scena

Re: [PERFORM] Odd sorting behaviour

2004-07-20 Thread Steinar H. Gunderson
On Thu, Jul 15, 2004 at 02:08:54PM +0200, Steinar H. Gunderson wrote: > sort_mem is already 16384, which I thought would be plenty -- I tried > increasing it to 65536 which made exactly zero difference. :-) I've tried some further tweaking, but I'm still unable to force it into doing a hash join -

Re: [PERFORM] NAS, SAN or any alternate solution ?

2004-07-20 Thread Grega Bremec
...and on Tue, Jul 20, 2004 at 09:52:56AM +0200, [EMAIL PROTECTED] used the keyboard: > Hi all, > > I've been searching the list for a while but couldn't find any up-to-date > information relating to my problem. > We have a production server with postgresql on cygwin that currently deels > with

Re: [PERFORM] NAS, SAN or any alternate solution ?

2004-07-20 Thread Grega Bremec
> > Oh, and not to forget - the price for a 3ware 9500S-12, the version > we're testing ranges between EUR1000 and EUR1500, depending on the > contract you have with the reseller and the intended use of the > device. SATA disks are dirt-cheap nowadays, as has been mentioned > before. > Correctio

Re: Réf. : Re: [PERFORM] NAS, SAN or any

2004-07-20 Thread Scott Marlowe
On Tue, 2004-07-20 at 03:32, [EMAIL PROTECTED] wrote: > Thanks a lot Scott. > > It seems that we were totally wrong when considering a network storage > solution. I've read your techdoc > http://techdocs.postgresql.org/guides/DiskTuningGuide and found many > interesting remarks. > I think that we

Re: [PERFORM] NAS, SAN or any alternate solution ?

2004-07-20 Thread Joe Conway
[EMAIL PROTECTED] wrote: Would NAS or SAN be good solutions ? (I've read that NAS uses NFS which could slow down the transfer rate ??) Has anyone ever tried one of these with postgresql ? Not (yet) with Postgres, but my company has run ~100GB Oracle database on NAS (NetApp) for the past couple

Re: [PERFORM] Odd sorting behaviour

2004-07-20 Thread Josh Berkus
Steinar, > I've tried some further tweaking, but I'm still unable to force it into > doing a hash join -- any ideas how I can find out why it chooses a merge > join? I'm sorry, I can't really give your issue the attention it deserves. At this point, I'd have to get a copy of your database, and

Re: [PERFORM] Odd sorting behaviour

2004-07-20 Thread Josh Berkus
Steinar, > I've tried some further tweaking, but I'm still unable to force it into > doing a hash join -- any ideas how I can find out why it chooses a merge > join? Actually, quick question -- have you tried setting enable_mergjoin=false to see the plan the system comes up with? Is it in fact

Re: [PERFORM] Odd sorting behaviour

2004-07-20 Thread Steinar H. Gunderson
On Tue, Jul 20, 2004 at 10:06:08AM -0700, Josh Berkus wrote: > Actually, quick question -- have you tried setting enable_mergjoin=false to > see the plan the system comes up with? Is it in fact faster? It is significantly faster -- 1200ms vs. 1900ms (on 7.4, at least). Some of the merge joins ar

Re: [PERFORM] NAS, SAN or any alternate solution ?

2004-07-20 Thread Rod Taylor
> Would NAS or SAN be good solutions ? (I've read that NAS uses NFS > which could slow down the transfer rate ??) > Has anyone ever tried one of these with postgresql ? I've used both a NetApp and Hitachi based SANs with PostgreSQL. Both work as well as expected, but do require some tweeking as t

[PERFORM] Unbearably slow cascading deletes

2004-07-20 Thread andrew
I have (among other things) a parent table with 200 records and a child table with 20MM or more. I set up referential integrity on the FK with ON DELETE CASCADE. It appears that when a DELETE is done on the parent table, the child table deletion is done with a sequential scan. I say this because

Re: [PERFORM] Unbearably slow cascading deletes

2004-07-20 Thread Stephan Szabo
On Tue, 20 Jul 2004 [EMAIL PROTECTED] wrote: > I have (among other things) a parent table with 200 records and a child > table with 20MM or more. I set up referential integrity on the FK with > ON DELETE CASCADE. > > It appears that when a DELETE is done on the parent table, the child > table del

Re: [PERFORM] Unbearably slow cascading deletes

2004-07-20 Thread Stephan Szabo
On Tue, 20 Jul 2004, Stephan Szabo wrote: > > On Tue, 20 Jul 2004 [EMAIL PROTECTED] wrote: > > > I have (among other things) a parent table with 200 records and a child > > table with 20MM or more. I set up referential integrity on the FK with > > ON DELETE CASCADE. > > > > It appears that when a

Re: [PERFORM] Unbearably slow cascading deletes

2004-07-20 Thread andrew
PREPARE c(int4) AS DELETE FROM childtable WHERE fk=$1; EXPLAIN EXECUTE c(-1); gives an index scan. PREPARE c2(int4) AS DELETE FROM parenttable WHERE key=$1; EXPLAIN EXECUTE c2(1); gives a seq scan on the parent table (itself a little curious) and no explanation of what the triggers are doing.

Re: [PERFORM] Unbearably slow cascading deletes

2004-07-20 Thread andrew
I FOUND IT! A second trigger that doesn't belong.. OK, we're set now, and thanks for showing me some ways to check what the planner is up to. Is there a way of seeing what the triggers will do? ---(end of broadcast)--- TIP 4: Don't 'kill -9' t

Re: [PERFORM] Unbearably slow cascading deletes

2004-07-20 Thread Christopher Kings-Lynne
I have (among other things) a parent table with 200 records and a child table with 20MM or more. I set up referential integrity on the FK with ON DELETE CASCADE. It appears that when a DELETE is done on the parent table, the child table deletion is done with a sequential scan. I say this because i

Re: [PERFORM] Odd sorting behaviour

2004-07-20 Thread Rod Taylor
> I could of course post the updated query plan if anybody is interested; let > me know. (The data is still available if anybody needs it as well, of > course.) I've taken a look and managed to cut out quite a bit of used time. You'll need to confirm it's the same results though (I didn't -- it is