| Subject | Re: [firebird-support] FB 2.0 / FB1.5 optimizer difference |
|---|---|
| Author | Dmitry Yemanov |
| Post date | 2006-12-03T02:56Z |
Hans wrote:
mentioned there. The fact that NOT IN is equal to <> ALL is implied, but
it's not very obvious for everybody.
v2.0 de-optimizes both ALL and NOT IN subqueries in order to guarantee a
consistent result.
Dmitry
> All I have been able to find on page 62 isSorry, this is my fault. It's on page 102, but only the ALL predicate is
>
> 'More Optimization of NOT Conditions'
> 'NOT conditions are simplified and optimized via an index when possible'
mentioned there. The fact that NOT IN is equal to <> ALL is implied, but
it's not very obvious for everybody.
v2.0 de-optimizes both ALL and NOT IN subqueries in order to guarantee a
consistent result.
Dmitry