Re: Query plan not using index for some reason. - Mailing list pgsql-general

From Tom Lane
Subject Re: Query plan not using index for some reason.
Date
Msg-id 5864.1033492425@sss.pgh.pa.us
Whole thread Raw
In response to Query plan not using index for some reason.  (Jean-Christian Imbeault <jc@mega-bucks.co.jp>)
List pgsql-general
Jean-Christian Imbeault <jc@mega-bucks.co.jp> writes:
> $ psql TMP -c "explain select products.id as pid from
> products,rel_genres_movies where maker_id='53' OR
> (rel_genres_movies.minor_id='11' AND rel_genres_movies.prod_id=products.id)"

Is that *really* the query you want to run?

Rows having maker_id=53 will be joined to *every* row of the other
table.  I'm suspecting you really wanted
    where (maker_id='53' OR rel_genres_movies.minor_id='11') AND
          rel_genres_movies.prod_id=products.id
so that the join behaves sensibly.

            regards, tom lane

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