Re: [PERFORM] Query taking too long. Problem reading explain output.

2007-10-10 Thread Ow Mun Heng
On Thu, 2007-10-04 at 08:30 -0400, Alvaro Herrera wrote: > Henrik wrote: > > > Ahh I had exactly 8 joins. > > Following your suggestion I raised the join_collapse_limit from 8 to 10 and > > the planners decision sure changed but now I have some crazy nested loops. > > Maybe I have some statistic

Re: [PERFORM] Query taking too long. Problem reading explain output.

2007-10-04 Thread Alvaro Herrera
Henrik wrote: > Correct. I changed the statistics to 500 in tbl_file.file_name and now the > statistics is better. But now my big seq scan on tbl_file_Structure back > and I don't know why. Hmm, I think the problem here is that it needs to fetch ~20 tuples from tbl_file_structure one way o

Re: [PERFORM] Query taking too long. Problem reading explain output.

2007-10-04 Thread Henrik
4 okt 2007 kl. 14:30 skrev Alvaro Herrera: Henrik wrote: Ahh I had exactly 8 joins. Following your suggestion I raised the join_collapse_limit from 8 to 10 and the planners decision sure changed but now I have some crazy nested loops. Maybe I have some statistics wrong? Yeah. The prob

Re: [PERFORM] Query taking too long. Problem reading explain output.

2007-10-04 Thread Alvaro Herrera
Henrik wrote: > Ahh I had exactly 8 joins. > Following your suggestion I raised the join_collapse_limit from 8 to 10 and > the planners decision sure changed but now I have some crazy nested loops. > Maybe I have some statistics wrong? Yeah. The problematic misestimation is exactly the innermo

Re: [PERFORM] Query taking too long. Problem reading explain output.

2007-10-04 Thread Henrik
3 okt 2007 kl. 16:15 skrev Tom Lane: Henrik <[EMAIL PROTECTED]> writes: Here is the query if needed. explain analyze SELECT file_name FROM tbl_file_structure JOIN tbl_file ON pk_file_id = fk_file_id JOIN tbl_structure ON pk_structure_id = fk_structure_id JOIN tbl_archive ON pk_archive_id =fk_a

Re: [PERFORM] Query taking too long. Problem reading explain output.

2007-10-03 Thread Tom Lane
Henrik <[EMAIL PROTECTED]> writes: > Here is the query if needed. > explain analyze SELECT file_name FROM tbl_file_structure JOIN > tbl_file ON pk_file_id = fk_file_id JOIN tbl_structure ON > pk_structure_id = fk_structure_id JOIN tbl_archive ON pk_archive_id > =fk_archive_id JOIN tbl_share O

Re: [PERFORM] Query taking too long. Problem reading explain output.

2007-10-03 Thread Michael Fuhr
On Wed, Oct 03, 2007 at 10:03:53AM +0200, Henrik wrote: > I have a little query that takes too long and what I can see in the > explain output is a seq scan on my biggest table ( tbl_file_structure) > which I can't explain why. Here's where almost all of the time is taken: > Hash Join (cost=8

[PERFORM] Query taking too long. Problem reading explain output.

2007-10-03 Thread Henrik
Hello list, I have a little query that takes too long and what I can see in the explain output is a seq scan on my biggest table ( tbl_file_structure) which I can't explain why. Here is the output. I hope this is formatted correctly. If not, let me know and I'll paste it somewhere. Pos