David Rowley <david.row...@2ndquadrant.com> writes: > So it looks like I've assumed that the Append path's partitioned_rels > will only ever be set for partitioned tables, but it can, in fact, be > set for UNION ALL parents too when the union children are partitioned > tables.
> As a discussion topic, I've attached a patch which does resolve the > error, but it also disables run-time pruning in this case. > There might be some way we can treat UNION ALL parents differently > when building the PartitionPruneInfos. I've just not thought of what > this would be just yet. If I can't think of that, I wonder if this is > a rare enough case not to bother with run-time partition pruning. So, IIUC, the issue is that for partitioning cases Append expects *all* its children to be partitions of the *same* partitioned table? That is, you could also break it with select * from partitioned_table_a union all select * from partitioned_table_b ? If so, maybe the best solution is to not allow a partitioning appendrel to be flattened into an appendrel generated in other ways (particularly, via UNION ALL). I also wonder whether it was a bad idea to treat these as the same kind of path/plan in the first place. regards, tom lane