Re: "SELECT .. WHERE NOT IN" query running for hours - Mailing list pgsql-performance

Scott Carey <scott@richrelevance.com> wrote:

> Often, the best query plans result from 'LEFT JOIN WHERE right
> side is NULL' rather than NOT EXISTS however.  I often get
> performance gains by switching NOT EXISTS queries to LEFT JOIN
> form.

Even in 8.4 and later?  I would think that the anti-join that Tom
added in 8.4 would always perform at least as well as the LEFT JOIN
technique you describe.

-Kevin