Re: Predicate migration on complex self joins

On Mon, Jul 13, 2009 at 3:48 PM, decibel<decibel@decibel.org> wrote:
> On Jul 13, 2009, at 1:06 PM, Simon Riggs wrote:
>>
>> Not just because of this but I wonder if we might benefit from an
>> optimizer setting specifically aimed at the foolishnesses of
>> automatically generated SQL.
>
>
> +1. And it's not just ORMs that do stupid things, I've seen crap like this
> come out of users too (not this exact case, but similar).
>

i've this come from users most of the time...
the few systems i have seen that generate sql, try to avoid using
complex queries and make simple ones and the JOIN them at the app
level...

> Perhaps what we really want is an "optimization level" GUC so that users can
> tell the backend how much overhead they want the optimizer to spend on
> trying to work around stupidity... :)

i wonder what the levels have to be:
- smart_sql
- application_generated_sql
- normal_user_sql
- xtremely_stupid_sql
- what_the_hell_sql

;)

--
Atentamente,
Jaime Casanova
Soporte y capacitación de PostgreSQL
Asesoría y desarrollo de sistemas
Guayaquil - Ecuador
Cel. +59387171157