Re: LIMIT Question
От | Scott Marlowe |
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Тема | Re: LIMIT Question |
Дата | |
Msg-id | dcc563d10802281532n3da2ee0dlc2114f23af8136b8@mail.gmail.com обсуждение исходный текст |
Ответ на | LIMIT Question (Terry Lee Tucker <terry@chosen-ones.org>) |
Ответы |
Re: LIMIT Question
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Список | pgsql-general |
On Thu, Feb 28, 2008 at 3:20 PM, Terry Lee Tucker <terry@chosen-ones.org> wrote: > When one uses LIMIT, as in LIMIT 1, is the entire query executed on the server > side, but only one record returned? > > -------------------------------------------------------------------------------------------------------- > PostgreSQL 7.4.19 on i686-redhat-linux-gnu, compiled by GCC gcc (GCC) 3.4.6 > 20060404 (Red Hat 3.4.6-9) Sometimes yes, sometimes no. Depends on how complex the query is and whether or not pgsql's query planner can see a shortcut or not. It's more likely that a later version will have the optimizations needed to do that than an older version like 7.4 I'd think. But I'd ask someone more expert on the planner like Tom to be sure.
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