Re: Strange query plan - Mailing list pgsql-general

From Martin Gainty
Subject Re: Strange query plan
Date
Msg-id BLU142-W282CDB2234A4AD42F87B20AE720@phx.gbl
Whole thread Raw
In response to Strange query plan  ("Dmitry Teslenko" <dteslenko@gmail.com>)
Responses Re: Strange query plan  ("Gauthier, Dave" <dave.gauthier@intel.com>)
List pgsql-general
the columns referenced in the predicate need to reference columns whichimplement indexes to avert FTS
Anyone else?
Martin
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> Date: Thu, 14 Aug 2008 14:57:09 +0400
> From: dteslenko@gmail.com
> To: pgsql-general@postgresql.org
> Subject: [GENERAL] Strange query plan
>
> Hello!
>
> I have following table:
>
> CREATE TABLE table1 (
> field1 INTEGER NOT NULL,
> field2 INTEGER NOT NULL,
> field3 CHARACTER(30),
> ... some more numeric fields)
>
> I have also those indexes:
>
> CREATE UNIQUE INDEX idx1 ON table1 USING btree (field3, field2, field1)
> CREATE INDEX idx2 ON table1 USING btree (field1, field3)
>
> Then I query this table with something like this:
>
> SELECT SUM(...) FROM table1 WHERE field3 = 'ABC' AND field1 <> 1
> GROUP BY field2
>
> And planner picks up a sequential scan of a table. Why does he?
>
> --
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> Q: Why is top-posting such a bad thing?
> A: Top-posting.
> Q: What is the most annoying thing in e-mail?
>
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