Re: [PERFORM] ECC RAM really needed?

2007-05-27 Thread Andrew Sullivan
On Sat, May 26, 2007 at 10:52:14AM -0400, [EMAIL PROTECTED] wrote: Do you want to be the one person who does notice a problem? :-) Right, and notice that when you notice the problem _may not_ be when it happens. The problem with errors in memory (or on disk controllers, another place not to

Re: [PERFORM] Feature suggestion : FAST CLUSTER

2007-05-27 Thread Jim C. Nasby
On Tue, May 22, 2007 at 09:29:00AM +0200, PFC wrote: This does not run a complete sort on the table. It would be about as fast as your seq scan disk throughput. Obviously, the end result is not as good as a real CLUSTER since the table will be made up of several ordered

Re: [PERFORM] Domains versus Check Constraints

2007-05-27 Thread Jim C. Nasby
On Tue, May 22, 2007 at 12:56:21PM -0400, Chander Ganesan wrote: Are there any performance improvements that come from using a domain over a check constraint (aside from the ease of management component)? No. Plus support for domain constraints isn't universal (plpgsql doesn't honor them, for

Re: [PERFORM] Simulate database fragmentation

2007-05-27 Thread Jim C. Nasby
On Wed, May 23, 2007 at 11:58:06AM -0700, Y Sidhu wrote: Is there any easy way to take a database and add/delete records to create fragmentation of the records and indexes. I am trying to recreate high vacuum times. Update random rows, then do a vacuum. That will result in free space in random

Re: [PERFORM] Memory allocation and Vacuum abends

2007-05-27 Thread Jim C. Nasby
What does top report as using the most memory? On Wed, May 23, 2007 at 11:01:24PM -0300, Leandro Guimar?es dos Santos wrote: Hi all, I have a 4 CPU, 4GB Ram memory box running PostgreSql 8.2.3 under Win 2003 in a very high IO intensive insert application. The application

Re: [PERFORM] Performance Problem with Vacuum of bytea table (PG 8.0.13)

2007-05-27 Thread Jim C. Nasby
On Fri, May 25, 2007 at 10:29:30AM +0200, Bastian Voigt wrote: Hi *, for caching large autogenerated XML files, I have created a bytea table in my database so that the cached files can be used by multiple servers. There are about 500 rows and 10-20 Updates per minute on the table. The

Re: [PERFORM] Domains versus Check Constraints

2007-05-27 Thread Stefan Kaltenbrunner
Jim C. Nasby wrote: On Tue, May 22, 2007 at 12:56:21PM -0400, Chander Ganesan wrote: Are there any performance improvements that come from using a domain over a check constraint (aside from the ease of management component)? No. Plus support for domain constraints isn't universal (plpgsql

Re: [PERFORM] Feature suggestion : FAST CLUSTER

2007-05-27 Thread PFC
On Sun, 27 May 2007 17:53:38 +0200, Jim C. Nasby [EMAIL PROTECTED] wrote: On Tue, May 22, 2007 at 09:29:00AM +0200, PFC wrote: This does not run a complete sort on the table. It would be about as fast as your seq scan disk throughput. Obviously, the end result is not as good as

Re: [PERFORM] Feature suggestion : FAST CLUSTER

2007-05-27 Thread Alexander Staubo
On 5/27/07, PFC [EMAIL PROTECTED] wrote: PostgreSQL humiliates InnoDB on CPU-bound workloads (about 2x faster since I run it on dual core ; InnoDB uses only one core). However, InnoDB can automatically cluster tables without maintenance. How does it know what to cluster by? Does it

Re: [PERFORM] Feature suggestion : FAST CLUSTER

2007-05-27 Thread PFC
How does it know what to cluster by? Does it gather statistics about query patterns on which it can decide an optimal clustering, or does it merely follow a clustering previously set up by the user? Nothing fancy, InnoDB ALWAYS clusters on the primary key, whatever it is. So, if you can

Re: [PERFORM] Postgres Benchmark Results

2007-05-27 Thread Chris
I am re-running it with other tuning, notably cost-based vacuum delay and less frequent checkpoints, and it is a *lot* smoother. These take a full night to run, so I'll post more results when I have usefull stuff to show. This has proven to be a very interesting trip to