Re: Expression errors with "FOR UPDATE" and postgres_fdw with partitionwise join enabled.

(2018/07/04 11:00), Etsuro Fujita wrote:
> (2018/07/04 1:35), Andres Freund wrote:
>> What's the plan forward here?
>
> I still think that this approach would be the right way to go, so I plan
> to polish the patch.

The approach would not require extra cycles where partitioning is not 
involved as discussed before, and makes code much simpler, which would 
make maintenance and the FDW author's life easy, so I still think that 
the approach would be the direction to go in.  So, I updated the patch. 
  Here are changes:

* I assumed that the child plan passed to adjust_subplan_tlist was a 
scan or join unless it was Append or MergeAppend, but I noticed I was 
wrong; if the topmost scan/join relation is partitioned, 
apply_scanjoin_target_to_paths might have pushed down ProjectSet or 
Result to each of partitions.  So, in that case the child's plan would 
have ProjectSet or Result atop the scan or join plan.  (I could not 
produce such an example, though.)  To address this, I modified 
build_childrel_tlist so that we just apply adjust_appendrel_attrs to the 
parent's targetlist to get the child's if the parent is the topmost 
scan/join relation.  So, we don't need to care about that in 
adjust_subplan_tlist.  I think this change would also increase the 
efficiency for that case.  I added regression test cases for that as well.

* I fixed an oversight in outfuncs.c.

* I renamed member variables I added to RelOptInfo before, and revised 
code/comments a bit.

Attached is an updated version of the patch.

Best regards,
Etsuro Fujita