On Fri, 31 Dec 2021 at 00:14, Yura Sokolov <y.soko...@postgrespro.ru> wrote: > Problem: > - Append path is created with explicitely parallel_aware = true > - It has two child, one is trivial, other is parallel_aware = false . > Trivial child is dropped. > - Gather/GatherMerge path takes Append path as a child and thinks > its child is parallel_aware = true. > - But Append path is removed at the last since it has only one child. > - Now Gather/GatherMerge thinks its child is parallel_aware, but it > is not. > Gather/GatherMerge runs its child twice: in a worker and in a leader, > and gathers same rows twice.
Thanks for the report. I can confirm that I can recreate the problem with your script. I will look into this further later next week. David
