On 2016/09/27 18:09, Ashutosh Bapat wrote:
>>> I tried to debug the problem somewhat. In set_append_rel_pathlist(),
>>> it finds that at least one child has a parameterized path as the
>>> cheapest path, so it doesn't create an unparameterized path for append
>>> rel. At the same time there is a parameterization common to all the
>>> children, so it doesn't create any path. There seem to be two problems
>>> here
>>> 1. The children from second level onwards may not be getting
>>> parameterized for lateral references. That seems unlikely but
>>> possible.
>
> Did you check this? We may be missing on creating index scan paths
> with parameterization. If we fix this, we don't need to
> re-parameterize Append.
You're right. How about the attached patch that fixes the problem along
these lines? The problem seems to be that multi-level inheritance sets
(partitioned tables) are not handled in create_lateral_join_info(), which
means that lateral_relids and lateral_referencers of the root relation are
not being propagated to the partitions below level 1.
I'm getting concerned about one thing though - for a given *regular*
inheritance set, the root->append_rel_list would be scanned only once; But
for a *partitioned table* inheritance set, it would be scanned for every
partitioned table in the set (ie, the root table and internal partitions).
Thanks,
Amit