more voodoo planner bs :)
От | D. Duccini |
---|---|
Тема | more voodoo planner bs :) |
Дата | |
Msg-id | Pine.GSO.4.03.10205071926410.20094-100000@ra.bpsi.net обсуждение исходный текст |
Ответы |
voodoo planner update
Re: more voodoo planner bs :) |
Список | pgsql-novice |
Can anyone tell me why the planner is penalizing me for changing ONE value? explain SELECT l.idsubaccount,1 as status,l.type,l.date,l.units,l.rate,l.total,l.text FROM lineitemsnext l, accounts a, subaccounts s WHERE a.billdate = 1 and a.id = s.idaccount and s.id = l.idsubaccount and l.text <> '' and l.date <= '2002-05-30' ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ here is what i get if a.billdate = 1 Hash Join (cost=46.55..241.82 rows=242 width=48) -> Hash Join (cost=11.49..185.31 rows=242 width=44) -> Seq Scan on subaccounts s (cost=0.00..57.36 rows=2836 width=8) -> Hash (cost=10.88..10.88 rows=242 width=36) -> Seq Scan on lineitemsnext l (cost=0.00..10.88 rows=242 width=36) -> Hash (cost=24.76..24.76 rows=940 width=4) -> Seq Scan on accounts a (cost=0.00..24.76 rows=940 width=4) EXPLAIN ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ here is what i get if a.billdate = 2 Nested Loop (cost=0.00..123.69 rows=1 width=48) -> Nested Loop (cost=0.00..117.57 rows=3 width=12) -> Seq Scan on accounts a (cost=0.00..24.76 rows=1 width=4) -> Seq Scan on subaccounts s (cost=0.00..57.36 rows=2836 width=8) -> Index Scan using idxlineitemsnextbysub on lineitemsnext l (cost=0.00..2.02 rows=1 width=36) EXPLAIN ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ when billdate = 1, its blazing fast when its any other value, it never really completes (ie, i stop it because its taking too long) ----------------------------------------------------------------------------- david@backpack.com BackPack Software, Inc. www.backpack.com +1 651.645.7550 voice "Life is an Adventure. +1 651.645.9798 fax Don't forget your BackPack!" -----------------------------------------------------------------------------
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