On Wed, 27 Feb 2019 at 13:41, Li, Zheng <zhe...@amazon.com> wrote: > We still check for inner side's nullability, when it is nullable we > append a "var is NULL" to the anti join condition. So every outer > tuple is going to evaluate to true on the join condition when there > is indeed a null entry in the inner.
That's possible, at least providing the var is NULL is an OR condition, but the problem there is that you force the plan into a nested loop join. That's unfortunately not going to perform very well when the number of rows to process is large. -- David Rowley http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
