On Tue, Apr 21, 2009 at 8:12 PM, <david@lang.hm> wrote:
>> Using prepared queries, at least if you use PQexecPrepared or
>> PQexecParams, also reduces the work required on the client to build the
>> whole string, and the parsing overhead on the database side to pull it
>> apart again. That's where the performance is going to be improved by
>> going that route, not so much in eliminating the planning.
>
> in a recent thread about prepared statements, where it was identified that
> since the planning took place at the time of the prepare you sometimes have
> worse plans than for non-prepared statements, a proposal was made to have a
> 'pre-parsed, but not pre-planned' version of a prepared statement. This was
> dismissed as a waste of time (IIRC by Tom L) as the parsing time was
> negligable.
>
> was that just because it was a more complex query to plan?
Joins are expensive to plan; a simple insert is not. I also disagree
that pre-parsed but not pre-planned is a waste of time, whoever said
it. Sometimes it's what you want, especially in PL/pgsql.
...Robert