Re: Indexes not used
От | D. Duccini |
---|---|
Тема | Re: Indexes not used |
Дата | |
Msg-id | Pine.GSO.4.03.10103161014500.5637-100000@ra.bpsi.net обсуждение исходный текст |
Ответ на | Re: Indexes not used (Tom Lane <tgl@sss.pgh.pa.us>) |
Список | pgsql-novice |
> 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 ----------------------------------------------------------------------------- david@backpack.com BackPack Software, Inc. www.backpack.com +1 651.645.7550 voice "Life is an Adventure. +1 651.645.9798 fax Don't forget your BackPack!" -----------------------------------------------------------------------------
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