Bruno Baguette napisal 13.11.2008 12:02:
Hello !
Sorry for the subject, I didn't found a better one ! :-/
I'm having a problem with this query (below) that takes betweend 14 and
15 seconds to run, which is too long for the end-user.
I've done a EXPLAIN ANALYZE (below below) but I'm having difficulties to
see which part of that query is taking so many times.
If the lines are too long, your mailreader may cut them and make the SQL
query and the query plan unreadable, so I've put a copy of them on
pastebin.com : <http://pastebin.com/m53ca365>
Can you give me some tips to see which part of the query is guilty ?
1. Your explain analyze points to a lot of loops in exists clause:
Filter: ((NOT is_deleted) AND (subplan))
16.5msec * 800loops = ~13sec.
Try to replace exists() with in() or inner joins/distinct.
2. Those 3 left joins can be replaced with subselects:
select (select count(*)... ) as societe_nbre_commandes
from societes ...
--
Regards,
Tomasz Myrta
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