On Tue, 14 May 2024, David Rowley wrote:
That assumes the Append won't ever use > 1 worker per subnode, but that's not the case for your plan as the subnodes are "Parallel". That means all the workers could be working on the same subnode which could result in one group being split between 2 or more workers.
Didn't think of that, makes sense!
Parallel Append can also run in a way that the Append child nodes will only get 1 worker each.
How can I tell which case it is, from the EXPLAIN output (for example the output at [1]) ? [1] https://www.postgresql.org/message-id/69077f15-4125-2d63-733f-21ce6eac4f01%40gmx.net Dimitris
