Re: Indexes not used

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От D. Duccini
Тема Re: Indexes not used
Дата
Msg-id Pine.GSO.4.03.10103161014500.5637-100000@ra.bpsi.net
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Ответ на Re: Indexes not used  (Tom Lane <tgl@sss.pgh.pa.us>)
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> If the system needs to fetch more than a small percentage of the
> records, then seqscan *will* be faster.  The issue you are dealing
> with seems to be misestimation of the retrieval percentage for this
> particular query, causing the planner to guess wrong about which
> kind of plan to use.

no worries...i'll try building a subset of the data and see if there is
some "threshhold" value

or...maybe its time i actually contributed some code to the project :)

i built an OO database engine a few years ago (in objective-c) that used a
modified N-tree approach to indicies that massively accelerated the
retrieval of a lot of "highly similar" data items

-duck

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