[PERFORM] 2 phase commit: performance implications?

2005-12-12 Thread Andy Ballingall
Hello, Clearly, I shouldn't actually use these transactions unless I have to, and in cases where I do use it, I'd expect the completion of the transaction to depend on the speed of all participating databases in the transaction, but are there any additional overheads which might come with a

[PERFORM] 7.4.7 vs. 8.1

2005-12-12 Thread Szabolcs BALLA
Hi, I am ready to install ver. 8.1 to our db server, but I have some questions about it. When I use autovacuum (8.1) is it required to use vacuum analyze for maintenance or autovacuum is enough? We have 2 processors (hyperthread) and is it needed to configure the psql to use it or is it

Re: [PERFORM] 7.4.7 vs. 8.1

2005-12-12 Thread Steinar H. Gunderson
On Mon, Dec 12, 2005 at 09:54:30AM +0100, Szabolcs BALLA wrote: When I use autovacuum (8.1) is it required to use vacuum analyze for maintenance or autovacuum is enough? autovacuum should be enough. We have 2 processors (hyperthread) and is it needed to configure the psql to use it or is

Re: [PERFORM] Very slow queries - please help

2005-12-12 Thread Bealach-na Bo
Thanks very much - there are a lot of good articles there... Reading as fast as I can :) Best, Bealach From: Thomas F. O'Connell [EMAIL PROTECTED] To: Bealach-na Bo [EMAIL PROTECTED] CC: PgSQL - Performance pgsql-performance@postgresql.org Subject: Re: [PERFORM] Very slow queries - please

Re: [PERFORM] How much expensive are row level statistics?

2005-12-12 Thread Alvaro Herrera
Michael Fuhr wrote: On Sun, Dec 11, 2005 at 11:53:36AM +, Carlos Benkendorf wrote: I would like to use autovacuum but is not too much expensive collecting row level statistics? The cost depends on your usage patterns. I did tests with one of my applications and saw no significant

Re: [PERFORM] Should Oracle outperform PostgreSQL on a complex

2005-12-12 Thread Luke Lonergan
Paal, On 12/12/05 2:10 AM, Pål Stenslet [EMAIL PROTECTED] wrote: Here are the schema details, but first a little introduction: Terrific, very helpful and thanks for both. I wonder why the bitmap scan isn't selected in this query, Tom might have some opinion and suggestions about it. I'd

Re: [PERFORM] How much expensive are row level statistics?

2005-12-12 Thread Merlin Moncure
On Sun, Dec 11, 2005 at 11:53:36AM +, Carlos Benkendorf wrote: I would like to use autovacuum but is not too much expensive collecting row level statistics? The cost depends on your usage patterns. I did tests with one of my applications and saw no significant performance

Re: [PERFORM] opinion on disk speed

2005-12-12 Thread Vivek Khera
On Dec 9, 2005, at 10:50 AM, Andreas Pflug wrote: Well, if your favourite dealer can't supply you with such common equipment as 15k drives you should consider changing the dealer. They don't seem to be aware of db hardware reqirements. Thanks to all for your opinions. I'm definitely

Re: [PERFORM] How much expensive are row level statistics?

2005-12-12 Thread Michael Fuhr
On Mon, Dec 12, 2005 at 01:33:27PM -0500, Merlin Moncure wrote: The cost depends on your usage patterns. I did tests with one of my applications and saw no significant performance difference for simple selects, but a series of insert/update/delete operations ran about 30% slower when

Re: [PERFORM] How much expensive are row level statistics?

2005-12-12 Thread Michael Fuhr
On Mon, Dec 12, 2005 at 10:23:42AM -0300, Alvaro Herrera wrote: Michael Fuhr wrote: The cost depends on your usage patterns. I did tests with one of my applications and saw no significant performance difference for simple selects, but a series of insert/update/delete operations ran about

Re: [PERFORM] opinion on disk speed

2005-12-12 Thread Vivek Khera
On Dec 8, 2005, at 2:21 PM, Jeffrey W. Baker wrote: For the write transactions, the speed and size of the DIMM on that LSI card will matter the most. I believe the max memory on that adapter is 512MB. These cost so little that it wouldn't make sense to go with anything smaller. From

Re: [PERFORM] opinion on disk speed

2005-12-12 Thread J. Andrew Rogers
On Dec 12, 2005, at 1:59 PM, Vivek Khera wrote: From where did you get LSI MegaRAID controller with 512MB? The 320-2X doesn't seem to come with more than 128 from the factory. Can you just swap out the DIMM card for higher capacity? We've swapped out the DIMMs on MegaRAID controllers.

Re: [PERFORM] opinion on disk speed

2005-12-12 Thread Vivek Khera
On Dec 12, 2005, at 5:16 PM, J. Andrew Rogers wrote: We've swapped out the DIMMs on MegaRAID controllers. Given the cost of a standard low-end DIMM these days (which is what the LSI controllers use last I checked), it is a very cheap upgrade. What's the max you can put into one of these

Re: [PERFORM] Small table or partial index?

2005-12-12 Thread Jim C. Nasby
On Fri, Dec 02, 2005 at 06:28:09PM -0500, Francisco Reyes wrote: I am in the process of designing a new system. There will be a long list of words such as -word table word_id integer word varchar special boolean Some special words are used to determine if some work is to be done and

Re: [PERFORM] Joining 2 tables with 300 million rows

2005-12-12 Thread Manfred Koizar
On Thu, 8 Dec 2005 11:59:24 -0500 , Amit V Shah [EMAIL PROTECTED] wrote: CONSTRAINT pk_runresult_has_catalogtable PRIMARY KEY (runresult_id_runresult, catalogtable_id_catalogtable, value) ' - Index Scan using runresult_has_catalogtable_id_runresult on runresult_has_catalogtable

Re: [PERFORM] How much expensive are row level statistics?

2005-12-12 Thread Tom Lane
Merlin Moncure [EMAIL PROTECTED] writes: The cost depends on your usage patterns. I did tests with one of my applications and saw no significant performance difference for simple selects, but a series of insert/update/delete operations ran about 30% slower when block- and row-level statistics

Re: [PERFORM] opinion on disk speed

2005-12-12 Thread Scott Marlowe
On Mon, 2005-12-12 at 16:19, Vivek Khera wrote: On Dec 12, 2005, at 5:16 PM, J. Andrew Rogers wrote: We've swapped out the DIMMs on MegaRAID controllers. Given the cost of a standard low-end DIMM these days (which is what the LSI controllers use last I checked), it is a very cheap

Re: [PERFORM] opinion on disk speed

2005-12-12 Thread J. Andrew Rogers
On Dec 12, 2005, at 2:19 PM, Vivek Khera wrote: On Dec 12, 2005, at 5:16 PM, J. Andrew Rogers wrote: We've swapped out the DIMMs on MegaRAID controllers. Given the cost of a standard low-end DIMM these days (which is what the LSI controllers use last I checked), it is a very cheap

Re: [PERFORM] How much expensive are row level statistics?

2005-12-12 Thread Michael Fuhr
On Mon, Dec 12, 2005 at 06:01:01PM -0500, Tom Lane wrote: IIRC, the only significant cost from enabling stats is the cost of transmitting the counts to the stats collector, which is a cost basically paid once at each transaction commit. So short transactions will definitely have more overhead

Re: [PERFORM] How much expensive are row level statistics?

2005-12-12 Thread Tom Lane
Michael Fuhr [EMAIL PROTECTED] writes: Further tests show that for this application the killer is stats_command_string, not stats_block_level or stats_row_level. I tried it with pgbench -c 10, and got these results: 41% reduction in TPS rate for stats_command_string 9%