Re: PG 7.4.3 optimizer choosing sequential scan. Why?
От
Barry S
Тема
Re: PG 7.4.3 optimizer choosing sequential scan. Why?
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Msg-id
e-udnSr_5vFHQZzcRVn-oA@giganews.com
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Re: PG 7.4.3 optimizer choosing sequential scan. Why? Barry S <barry@nospam.4.me.thx.com>
Re: PG 7.4.3 optimizer choosing sequential scan. Why? Greg Stark <gsstark@mit.edu>
> * The table contains one index: P1_NRN_ROAD_V (v, sobjid) (The index > includes the column sobjid because the query projects this col, and its > inclusion in the index allows it to be serviced without accessing the > underlying table) > Now, for the queries: > > QUERY 2: select sobjid from p1_nrn_road where v = 1 > > The plan is "Seq Scan on p1_nrn_road (cost=0.00..22158.54 rows=2 width=8)" > > That is puzzling. However, if you are only going to make a selection criteria for 'v', why the multi-column index? Setting an index on only 'v' should produce better results... -Barry
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