Re: [PERFORM] HashAggregate slower than sort?

Hi Kevin, Thanks for the suggestions. I've already converted all of my SQL to use distinct on (...) and this is now always faster using the hash-aggregates than when using sorting. The queries now only use sorting if the hashing would take up too much memory. Thanks, --Jatinder -Original

Re: [PERFORM] HashAggregate slower than sort?

Jatinder Sangha j...@coalition.com wrote: I've already converted all of my SQL to use distinct on (...) and this is now always faster using the hash-aggregates than when using sorting. The queries now only use sorting if the hashing would take up too much memory. It's great that you have

[PERFORM] Low perfomance SUM and Group by large databse

Hi, I'm getting low performance on SUM and GROUP BY queries. How can I improve my database to perform such queries. Here is my table schema: = \d acct_2010_25 Tabela public.acct_2010_25 Coluna |Tipo | Modificadores

Re: [PERFORM] Slow function in queries SELECT clause.

Thanks Tom, Your concepts of inlining and black box really cleared things up for me. With fnc_unit_convert() written in SQL and declared as STABLE I indeed have fast performance now. I appreciate the note on the IMMUTABLE part. The table contents should not change in a way to affect the

Re: [PERFORM] Aggressive autovacuuming ?

Excerpts from Scott Marlowe's message of dom jun 20 16:13:15 -0400 2010: On Sun, Jun 20, 2010 at 11:44 AM, Jesper Krogh jes...@krogh.cc wrote: Hi. I have been wondering if anyone has been experimenting with really agressive autovacuuming. I have been using moderately aggressive

Re: [PERFORM] Aggressive autovacuuming ?

Jesper Krogh jes...@krogh.cc wrote: My thought was that if I tuned autovacuum to be really aggressive then I could get autovacuum to actually vacuum the tuples before they get evicted from the OS cache thus effectively saving the IO-overhead of vacuuming. Interesting concept. That might

Re: [PERFORM] mysql to postgresql, performance questions

On 31 March 2010 15:23, Bruce Momjian br...@momjian.us wrote: James Mansion wrote: Hannu Krosing wrote: Pulling the plug should not corrupt a postgreSQL database, unless it was using disks which lie about write caching. Didn't we recently put the old wife's 'the disks lied' tale to bed in

Re: [PERFORM] mysql to postgresql, performance questions

On Mon, Jun 21, 2010 at 12:02 PM, Thom Brown thombr...@gmail.com wrote: I thought I'd attempt to renew discussion of adding PostgreSQL support to MythTV, but here's the response: It is not being actively developed to my knowledge and we have no intention of _ever_ committing such patches. Any

Re: [PERFORM] Low perfomance SUM and Group by large databse

On 21/06/10 22:42, Sergio Charpinel Jr. wrote: Hi, I'm getting low performance on SUM and GROUP BY queries. How can I improve my database to perform such queries. - Sort (cost=3499863.27..3523695.89 rows=9533049 width=50) (actual time=165468.022..168908.828 rows=9494165

Re: [PERFORM] PostgreSQL as a local in-memory cache

On Thu, Jun 17, 2010 at 1:29 PM, Josh Berkus j...@agliodbs.com wrote: a) Eliminate WAL logging entirely In addition to global temporary tables, I am also planning to implement unlogged tables, which are, precisely, tables for which no WAL is written. On restart, any such tables will be