Re: Reallife szenario for GEQO
От | Bernd Helmle |
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Тема | Re: Reallife szenario for GEQO |
Дата | |
Msg-id | 4003E1AB.2040105@oopsware.de обсуждение исходный текст |
Ответ на | Re: Reallife szenario for GEQO (Richard Huxton <dev@archonet.com>) |
Ответы |
Re: Reallife szenario for GEQO
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Список | pgsql-general |
Richard Huxton wrote: > On Tuesday 13 January 2004 09:50, Bernd Helmle wrote: > > > > I don't think it's that it provides a better plan, just that it comes up with > a quicker solution. Searching all possible paths is not practical for a large > number of tables, so you need another approach. > Aggreed. That was my opinion, too. Sorry for my unclear statement. > Google for "travelling salesman problem" for discussion of the sort of > thinking behind it. > That was the first thing i've done. I understand the theoretical background, but i need a practical scenario, to show: QUERY A with GEQO QUERY A without GEQO And then compare the specific query plan generation efficency. In this case I have to think about a practical database scenario, to execute such queries. If i have enough tables i can join against, i should see an improvement, in theory. But what means "enough tables"? So i wonder, if anyone had done such a comparison already. Thanks for your reply, Bernd
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