Subject Re: [firebird-support] Problem with not in queries in Firebird 2.0 RC3
Author Dmitry Yemanov
"Graeme Edwards" <g.edwards@...> wrote:
> It appears to me that if I now attempt to run a query with a not in clause

It's a bugfix, actually. NOT IN and ALL don't use indices anymore, as it may
cause wrong results in some cases (we had three related bugreports). But as
subqueries still executed per every master row, you'll have a very long
execution time. Sad but true.

A workaround is to use a left outer join with IS NULL clause in the WHERE