pg.ddx.io pgsql-sql@postgresql.org mailing list archive
help / color / mirror / Atom feedproblem with slow select
3+ messages / 3 participants
[nested] [flat]
* problem with slow select
@ 2004-04-21 15:00 francescosaf <francescosaf.152kao@mail.webservertalk.com>
2004-04-26 18:58 ` Re: problem with slow select Rod Taylor <pg@rbt.ca>
0 siblings, 1 reply; 3+ messages in thread
From: francescosaf @ 2004-04-21 15:00 UTC (permalink / raw)
To: pgsql-sql
hi
I have two tables:
table: XXXX
idcode varchar(15) -->references (idcode) table YYYY
latitude float
longitude float
time timestamp
p_a char(1)
barcode....
address....
idprog serial... -->primary key
flag boolean
table YYYY
idfact numeric(7,0) --->references .....
idcode varchar(15) --->primary key
name varchar(20)
I want to exctract the last operation of table XXXX for each idcode of
table YYYY where idfact=123
I HAVE THIS QUERY BUT IT IS TOO SLOW (10 SECONDS):
select XXXX.*,YYYY.name from YYYY,XXXX join (select
XXXX.idcode,max(XXXX.tempo) as tempo from XXXX,YYYY where
YYYY.idfact=123 and XXXX.idcode=YYYY.idcode group by XXXX.idcode)
temptable on (temptable.tempo=XXXX.tempo and
temptable.idcode=XXXX.idcode) where YYYY.idfact=123 and
XXXX.idcode=YYYY.idcode order by YYYY.name;
PLEASE HELP ME
--
francescosaf
------------------------------------------------------------------------
Posted via http://www.webservertalk.com
------------------------------------------------------------------------
View this thread: http://www.webservertalk.com/message189539.html
^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: problem with slow select
2004-04-21 15:00 problem with slow select francescosaf <francescosaf.152kao@mail.webservertalk.com>
@ 2004-04-26 18:58 ` Rod Taylor <pg@rbt.ca>
0 siblings, 0 replies; 3+ messages in thread
From: Rod Taylor @ 2004-04-26 18:58 UTC (permalink / raw)
To: francescosaf <francescosaf.152kao@mail.webservertalk.com>; +Cc: pgsql-sql
On Wed, 2004-04-21 at 11:00, francescosaf wrote:
> hi
>
> I have two tables:
Please send results of EXPLAIN ANALYZE for the query in question.
Thanks
^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: problem with slow select
@ 2004-04-30 09:25 francescosaf <francescosaf.15irmp@mail.webservertalk.com>
0 siblings, 0 replies; 3+ messages in thread
From: francescosaf @ 2004-04-30 09:25 UTC (permalink / raw)
To: pgsql-sql
thank you for answer and excuse me for later
this is query plan:
QUERY PLAN
---------------------------------------------------------------------------------------------------------------------------------------------------------------
Nested Loop (cost=10564.42..10853.74 rows=1 width=150) (actual
time=11626.89..12060.36 rows=6 loops=1)
-> Merge Join (cost=10564.42..10820.69 rows=6 width=131) (actual
time=11626.45..12058.84 rows=6 loops=1)
Merge Cond: (("outer".idcode = "inner".idcode) AND
("outer".time = "inner".time))
-> Sort (cost=7550.07..7675.40 rows=50134 width=104) (actual
time=8910.91..9031.23 rows=49293 loops=1)
Sort Key: XXXX.idcode, XXXX.time
-> Seq Scan on XXXX (cost=0.00..1586.34 rows=50134
width=104) (actual time=0.10..852.78 rows=50515 loops=1)
-> Sort (cost=3014.35..3017.11 rows=1102 width=31) (actual
time=2419.43..2419.45 rows=6 loops=1)
Sort Key: temptable.idcode, temptable.time
-> Subquery Scan temptable (cost=2876.08..2958.70
rows=1102 width=31) (actual time=2154.84..2419.15 rows=6 loops=1)
-> Aggregate (cost=2876.08..2958.70 rows=1102
width=31) (actual time=2154.83..2419.10 rows=6 loops=1)
-> Group (cost=2876.08..2931.16 rows=11016
width=31) (actual time=2066.58..2389.91 rows=19486 loops=1)
-> Sort (cost=2876.08..2903.62
rows=11016 width=31) (actual time=2066.55..2106.39 rows=19486 loops=1)
Sort Key: XXXX.idcode
-> Hash Join
(cost=36.50..2136.54 rows=11016 width=31) (actual time=3.41..765.49
rows=19486 loops=1)
Hash Cond: ("outer".idcode
= "inner".idcode)
-> Seq Scan on XXXX
(cost=0.00..1586.34 rows=50134 width=21) (actual time=0.12..301.87
rows=50515 loops=1)
-> Hash
(cost=36.48..36.48 rows=7 width=10) (actual time=3.10..3.10 rows=0
loops=1)
-> Seq Scan on YYYY
(cost=0.00..36.48 rows=7 width=10) (actual time=0.13..3.04 rows=6
loops=1)
Filter:
((idazien = 8::numeric) OR (idazien = 1019::numeric))
-> Index Scan using YYYY_pkey on YYYY (cost=0.00..5.46 rows=1
width=19) (actual time=0.17..0.18 rows=1 loops=6)
Index Cond: (YYYY.idcode = "outer".idcode)
Filter: ((idazien = 8::numeric) OR (idazien = 1019::numeric))
Total runtime: 12065.05 msec
(23 rows)
--
francescosaf
------------------------------------------------------------------------
Posted via http://www.webservertalk.com
------------------------------------------------------------------------
View this thread: http://www.webservertalk.com/message189539.html
^ permalink raw reply [nested|flat] 3+ messages in thread
end of thread, other threads:[~2004-04-30 09:25 UTC | newest]
Thread overview: 3+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2004-04-21 15:00 problem with slow select francescosaf <francescosaf.152kao@mail.webservertalk.com>
2004-04-26 18:58 ` Rod Taylor <pg@rbt.ca>
2004-04-30 09:25 Re: problem with slow select francescosaf <francescosaf.15irmp@mail.webservertalk.com>
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox