> If the sort is the inner input to a merge join, this could reflect > mark-and-restore rescanning of the sort's output. Are there a > whole lot of duplicate keys on the merge's other side?
Yes. The course_id column's values repeat a LOT on the merge side.
Dane Foster <studdugie@gmail.com> writes: > I'm trying to understand a bit of weirdness in a plan output. There is a > sort node above a sequential scan node where the scan node produces 26,026 > rows yet the sort node above it produces 42,995,408. How is it possible to > sort more data than you received?
If the sort is the inner input to a merge join, this could reflect mark-and-restore rescanning of the sort's output. Are there a whole lot of duplicate keys on the merge's other side?
