Re: Optimizer + bind variables

On 11/3/09 4:18 PM, "David Kerr" <dmk(at)mr-paradox(dot)net> wrote:

> On Wed, Nov 04, 2009 at 11:02:22AM +1100, Chris wrote:
> - David Kerr wrote:
> - >On Wed, Nov 04, 2009 at 07:43:16AM +0800, Craig Ringer wrote:
> - >- David Kerr wrote:
> - No.
> -
> - This is explained in the notes here:
> -
> - http://www.postgresql.org/docs/current/static/sql-prepare.html
>
> <sigh> and i've read that before too.
>
> On the upside, then it behaves like I would expect it to, which is
> good.
>
> Thanks
>
> Dave

Note that the query plan can often be the same for the example here.

It depends on whether the knowledge of the exact value makes a difference.

The most common case is an identifier column.
If the column is unique and indexed, and the parameter is an exact = match
in the where clause to that column, the plans won't differ.

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