Tom Lane wrote:
> "Richard Broersma" <richard.broersma@gmail.com> writes:
>
>>There is one possible alteration that may or many not improve
>>performance. This would be to replace the EXISTS with a LEFT JOIN
>>WHERE IS NOT NULL;
>
>
> That changes the behavior, doesn't it? Or is event_log_no a unique
> key for Myevents? I think what you want is to make the EXISTS an IN
> instead.
>
> regards, tom lane
>
>
Yes event_log_no is a unique key for myevents.
