Re: [PERFORM] select on 22 GB table causes An I/O error occured while sending to the backend. exception

2008-08-29 Thread Valentin Bogdanov
In 2003 I met this guy who was doing Computation Fluid Dynamics and he had to use this software written by physics engineers in FORTRAN. 1 Gig of ram wasn't yet the standard for a desktop pc at that time but the software required at least 1 Gig just to get started. So I thought what is the

Re: [PERFORM] Using PK value as a String

2008-08-11 Thread Valentin Bogdanov
--- On Mon, 11/8/08, Gregory Stark [EMAIL PROTECTED] wrote: From: Gregory Stark [EMAIL PROTECTED] Subject: Re: [PERFORM] Using PK value as a String To: Jay [EMAIL PROTECTED] Cc: pgsql-performance@postgresql.org Date: Monday, 11 August, 2008, 10:30 AM Jay [EMAIL PROTECTED] writes: I have

Re: [PERFORM] Database size Vs performance degradation

2008-07-30 Thread Valentin Bogdanov
I am guessing that you are using DELETE to remove the 75,000 unimportant. Change your batch job to CREATE a new table consisting only of the 5,000 important. You can use CREATE TABLE table_name AS select_statement command. Then drop the old table. After that you can use ALTER TABLE to change the

Re: [PERFORM] Perl/DBI vs Native

2008-07-23 Thread Valentin Bogdanov
Thanks Guys, this is really useful, especially the pg_service.conf. I have got an app where the connection parameters have to be set in 3 different places I was thinking of writing something myself but now that I know of pg_service.conf, problem solved. Regards, Val --- On Tue, 22/7/08,

Re: [PERFORM] Perl/DBI vs Native

2008-07-22 Thread Valentin Bogdanov
Thanks to everyone who replied. There were some really good points. However, I found what is causing the difference. The perl program was connecting to the database via a TCP socket while the C version was using Unix socket. I changed the connect in my perl script, so that it now uses Unix

[PERFORM] Perl/DBI vs Native

2008-07-21 Thread Valentin Bogdanov
Hi, I have ran quite a few tests comparing how long a query takes to execute from Perl/DBI as compared to psql/pqlib. No matter how many times I run the test the results were always the same. I run a SELECT all on a fairly big table and enabled the log_min_duration_statement option. With psql

[PERFORM] postgres overall performance seems to degrade when large SELECT are requested

2008-05-14 Thread Valentin Bogdanov
HI, I have an application that maintains 150 open connections to a Postgres DB server. The application works fine without a problem for the most time. The problem seem to arise when a SELECT that returns a lot of rows is executed or the SELECT is run on a large object. These selects are run