Re: [GENERAL] [PERFORM] Inaccurate Explain Cost

2012-09-28 Thread Matthias
Am 27.09.2012, 02:04 Uhr, schrieb Jeff Janes jeff.ja...@gmail.com: On Wed, Sep 26, 2012 at 1:21 PM, hubert depesz lubaczewski dep...@depesz.com wrote: On Wed, Sep 26, 2012 at 02:38:09PM -0400, Robert Sosinski wrote: The first query shows a cost of 190,169.55 and runs in 199,806.951 ms. When I

[PERFORM] Inaccurate Explain Cost

2012-09-26 Thread Robert Sosinski
Hey Everyone, I seem to be getting an inaccurate cost from explain. Here are two examples for one query with two different query plans: exchange_prod=# set enable_nestloop = on; SET exchange_prod=# exchange_prod=# explain analyze SELECT COUNT(DISTINCT exchange_uploads.id) FROM

Re: [PERFORM] Inaccurate Explain Cost

2012-09-26 Thread Shaun Thomas
On 09/26/2012 01:38 PM, Robert Sosinski wrote: I seem to be getting an inaccurate cost from explain. Here are two examples for one query with two different query plans: Well, there's this: Nested Loop (cost=0.00..151986.53 rows=2817 width=4) (actual time=163.275..186869.844 rows=43904

Re: [PERFORM] Inaccurate Explain Cost

2012-09-26 Thread hubert depesz lubaczewski
On Wed, Sep 26, 2012 at 02:38:09PM -0400, Robert Sosinski wrote: The first query shows a cost of 190,169.55 and runs in 199,806.951 ms. When I disable nested loop, I get a cost of 2,535,992.34 which runs in only 133,447.790 ms. We have run queries on our database with a cost of 200K cost

Re: [PERFORM] Inaccurate Explain Cost

2012-09-26 Thread Samuel Gendler
On Wed, Sep 26, 2012 at 1:21 PM, hubert depesz lubaczewski dep...@depesz.com wrote: On Wed, Sep 26, 2012 at 02:38:09PM -0400, Robert Sosinski wrote: The first query shows a cost of 190,169.55 and runs in 199,806.951 ms. When I disable nested loop, I get a cost of 2,535,992.34 which runs in

Re: [GENERAL] [PERFORM] Inaccurate Explain Cost

2012-09-26 Thread Jeff Janes
On Wed, Sep 26, 2012 at 1:21 PM, hubert depesz lubaczewski dep...@depesz.com wrote: On Wed, Sep 26, 2012 at 02:38:09PM -0400, Robert Sosinski wrote: The first query shows a cost of 190,169.55 and runs in 199,806.951 ms. When I disable nested loop, I get a cost of 2,535,992.34 which runs in