Re: Query optimizer & prepared statements

Jack Orenstein wrote:
> If x is an integer column with an index, then
>
> select ...
> from T
> where x > 1
>
> and
>
> select ...
> from T
> where x > 1000000000
>
> could be optimized differently. So how is optimization done for a
> prepared statement containing a variable, e.g.
>
> select ...
> from T
> where x > $1

http://www.postgresql.org/docs/current/static/sql-prepare.html#AEN58703
explains this.

If your parameter is a unique key, then you won't see any difference. If
your parameter is a non-unique key, there may be differences depending
on your data/distribution etc.

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