Re: index / sequential scan problem
От | Fabian Kreitner |
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Тема | Re: index / sequential scan problem |
Дата | |
Msg-id | 5.1.0.14.0.20030717131157.03957fa0@195.145.148.245 обсуждение исходный текст |
Ответ на | Re: index / sequential scan problem (Paul Thomas <paul@tmsl.demon.co.uk>) |
Ответы |
Re: index / sequential scan problem
Re: index / sequential scan problem |
Список | pgsql-performance |
At 12:12 17.07.2003, you wrote: >On 17/07/2003 10:01 Fabian Kreitner wrote: > >Hi Fabian, > >When you are doing these kinds of tests, you need to be aware that the >kernel may have most of your data cached after the first query and this >may be why the second query appears to run faster. I thought of this too, but executions times wont change with repeating / alternating these two tests. >Also don't be worried if the planner chooses a seq scan for small tables >as the whole table can often be bought into memory with one IO whereas >reading the index then the table would be 2 IOs. HTH That is what I read too and is why Im confused that the index is indeed executing faster. Can this be a problem with the hardware and/or postgress installation? Thanks, Fabian
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