Re: Left Join Not Using Index?
От | Tom Lane |
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Тема | Re: Left Join Not Using Index? |
Дата | |
Msg-id | 24304.1051075805@sss.pgh.pa.us обсуждение исходный текст |
Ответ на | Re: Left Join Not Using Index? (Hunter Hillegas <lists@lastonepicked.com>) |
Ответы |
Re: Left Join Not Using Index?
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Список | pgsql-general |
Hunter Hillegas <lists@lastonepicked.com> writes: > Can anyone point me in another direction to optimize this AFAICS you cannot improve that without changing the query structure and/or the database layout. Because the WHERE clause is a bunch of OR'd conditions, it's useless for restricting either individual table scan making up the join --- there is really no implementation short of forming the entire join described by the FROM ... JOIN ... ON ... part of the query and then testing each individual row against the WHERE clause. While that is the abstract semantic model implied by the SQL spec, it's not exactly how you want a query to really be done :-(. regards, tom lane
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