Re: [SQL] optimizing 2-table join w/millions of rows

At 18:10 +0200 on 23/11/98, Tom Lane wrote:

> Here, indexes on the part number would be stressed. You'd have to
> experiment to see which is faster on your data. (As far as I know,
> the Postgres optimizer will always evaluate your AND clauses left to
> right, which means that the key to performance is to make the leftmost
> clause reject as large a fraction of candidate rows as possible.)

I thought the optimizer canonized the where clause into an ANDing of ORs,
and then sought the best solution. That is, that the order of the clauses
did not matter, because the optimizer would know that comparison to a
literal on an indexed column is better than comparison to a field.

Herouth

--
Herouth Maoz, Internet developer.
Open University of Israel - Telem project
http://telem.openu.ac.il/~herutma