Re: Query slow as Function
От | Andreas Kretschmer |
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Тема | Re: Query slow as Function |
Дата | |
Msg-id | 20120218160244.GA23315@tux обсуждение исходный текст |
Ответ на | Query slow as Function (Steve Horn <steve@stevehorn.cc>) |
Ответы |
Re: Query slow as Function
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Список | pgsql-performance |
Steve Horn <steve@stevehorn.cc> wrote: > Execute the function: select * from geocode_carrier_route_by_geocode('xyz'); > > This query takes 500 milliseconds to run. My question of course is why? Wild guess: The planner doesn't know the actual value of the input-parameter, so the planner doesn't use the Index. > > Related: If I create a function and assign LANGUAGE 'sql', my function runs in > the expected 10 milliseconds. Is there some overhead to using the plpgsql > language? The planner, in this case, knows the actual value. > > Thanks for any help in clarifying my understanding! You can check the plan with the auto_explain - Extension, and you can force the planner to create a plan based on the actual input-value by using dynamic SQL (EXECUTE 'your query string' inside the function) As i said, wild guess ... Andreas -- Really, I'm not out to destroy Microsoft. That will just be a completely unintentional side effect. (Linus Torvalds) "If I was god, I would recompile penguin with --enable-fly." (unknown) Kaufbach, Saxony, Germany, Europe. N 51.05082°, E 13.56889°
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