Re: [PERFORM] Defining performance.

2006-12-01 Thread Heikki Linnakangas
Paul Lathrop wrote: We run 4 ~25-30Gb databases which cache information from eBay. These databases have had performance issues since before I joined the company. The databases have gone through a number of iterations. Initially, they were deployed as one huge database - performance was apparently

Re: [PERFORM] Defining performance.

2006-11-30 Thread Tobias Brox
[Chris - Fri at 02:32:05PM +1100] > Not really. A bad query is a bad query (eg missing a join element). It > won't show up for 3000 rows, but will very quickly if you increase that > by a reasonable amount. Even as simple as a missing index on a join > column won't show up for a small dataset bu

Re: [PERFORM] Defining performance.

2006-11-30 Thread Chris
Tobias Brox wrote: [EMAIL PROTECTED] - Thu at 06:37:12PM -0600] As my dataset has gotten larger I have had to throw more metal at the problem, but I have also had to rethink my table and query design. Just because your data set grows linearly does NOT mean that the performance of your query is

Re: [PERFORM] Defining performance.

2006-11-30 Thread Tobias Brox
[EMAIL PROTECTED] - Thu at 06:37:12PM -0600] > As my dataset has gotten larger I have had to throw more metal at the > problem, but I have also had to rethink my table and query design. Just > because your data set grows linearly does NOT mean that the performance of > your query is guaranteed to

Re: [PERFORM] Defining performance.

2006-11-30 Thread nospam
> 4) Much of my reading of the PG docs and list archives seems to suggest that much of performance tuning is done at the query level - you have to know how to ask for information in an efficient way. Performance does not exist in a vacuum (ho ho, PostgreSQL joke). The person writing the queries h

Re: [PERFORM] Defining performance.

2006-11-30 Thread Tobias Brox
[Jeff Davis - Thu at 04:57:54PM -0800] > > We're having the same issues, so we do the dumping and restoring every > > now and then to be sure everything is properly cleaned up. With 8.1. > > > > What's causing that? Is it index bloat? > > I would think a REINDEX would avoid having to dump/resto

Re: [PERFORM] Defining performance.

2006-11-30 Thread Jeff Davis
On Fri, 2006-12-01 at 01:05 +0100, Tobias Brox wrote: > > However, we still are suffering a gradual decrease in performance over > > time - or so the application engineers claim. The DBA and I have been > > banging our heads against this for a month. > > We're having the same issues, so we do the

Re: [PERFORM] Defining performance.

2006-11-30 Thread Scott Marlowe
On Thu, 2006-11-30 at 18:26, Tom Lane wrote: > Paul Lathrop <[EMAIL PROTECTED]> writes: > > ... When I joined the company last year, the databases were > > deployed on 12-disk RAID5 arrays on dual-proc AMD machines with 4Gb of > > RAM, running Debian Woody and Postgres 7.2. These systems seemed to

Re: [PERFORM] Defining performance.

2006-11-30 Thread Tom Lane
Paul Lathrop <[EMAIL PROTECTED]> writes: > ... When I joined the company last year, the databases were > deployed on 12-disk RAID5 arrays on dual-proc AMD machines with 4Gb of > RAM, running Debian Woody and Postgres 7.2. These systems seemed to > suffer a gradually decreasing performance accompani

Re: [PERFORM] Defining performance.

2006-11-30 Thread Tobias Brox
[Paul Lathrop - Thu at 02:59:27PM -0800] > growing disk space usage. The DBA had come to the conclusion that the > VACUUM command did/does not work on these systems, because even after a > VACUUM FULL, the size of the database was continually increasing. So, as > things stand with the PG7.2 machine

[PERFORM] Defining performance.

2006-11-30 Thread Paul Lathrop
Hello all, I've been struggling with some performance questions regarding our Postgres databases. Here's the background: We run 4 ~25-30Gb databases which cache information from eBay. These databases have had performance issues since before I joined the company. The databases have gone through a