Re: join optimization problem - Mailing list pgsql-sql

From Toby Tremayne
Subject Re: join optimization problem
Date
Msg-id 200308032020.52741.toby@lyricist.com.au
Whole thread Raw
In response to Re: join optimization problem  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: join optimization problem  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-sql
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Hi Tom,
yes I re-run vacuum analyze every time I muck about with the tables/ indexes.
The output of explain analyze is this:

Sort  (cost=1660930.18..1660946.63 rows=6581 width=568) (actual
time=545668.58..545675.05 rows=1537 loops=1)  Sort Key: max(m.date_created)  ->  Aggregate  (cost=0.00..1659452.99
rows=6581width=568) (actual  
time=614.83..544598.17 rows=1537 loops=1)        ->  Group  (cost=0.00..1659123.95 rows=65807 width=568) (actual
time=539.87..543988.21 rows=1537 loops=1)              ->  Nested Loop  (cost=0.00..1657643.30 rows=65807 width=568)
(actual time=539.82..543404.25 rows=1537 loops=1)                    Join Filter: ("inner".thread_id =
("outer".thread_id)::double precision)                    ->  Index Scan using fbof_group_idx on fbof_thread t
(cost=0.00..642.03 rows=1537 width=548) (actual time=29.27..1043.40 rows=1537
loops=1)                          Filter: ((forum_id = 1::double precision) AND
(barchived = 0) AND (bsticky = 0))                    ->  Seq Scan on fbof_msg m  (cost=0.00..949.63 rows=8563
width=20) (actual time=0.08.. 294.28 rows=8563 loops=1537)Total runtime: 545763.83 msec
(10 rows)

any input at all would be great.
cheers,
Toby


On Friday 01 August 2003 10:36, Tom Lane wrote:
> Toby Tremayne <toby@lyricist.com.au> writes:
> > the explain data I'm currently getting is this:
>
> "explain analyze" would be much more useful.
>
> Also, I assume you've vacuum analyzed these tables recently?
>
>             regards, tom lane

- --

- --------------------------------
 Life is poetry -    write it in your own words

- --------------------------------

Toby Tremayne
Code Poet and Zen Master of the Heavy Sleep
Senior Technical Consultant
Lyricist Software
www.lyricist.com.au
+61 416 048 090
ICQ: 13107913


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