On Tue, 10 Mar 2020 at 00:13, David Rowley <dgrowle...@gmail.com> wrote: > Over in inheritance_planner(), I noticed that the RT index of the > SELECT query and the UPDATE/DELETE query can differ. There was some > code that performed translations. I changed that code slightly so that > it's a bit more optimal. It was building two lists, one for the old > RT index and one for the new. It added elements to this list > regardless of if the RT indexes were the same or not. I've now changed > that to only add to the list if they differ, which I feel should never > be slower and most likely always faster. I'm also now building a > translation map between the old and new RT indexes, however, I only > found one test in the regression tests which require any sort of > translation of these RT indexes. This was with an inheritance table, > so I need to do a bit more work to find a case where this happens with > a partitioned table to ensure all this works.
I had a closer look at this today and the code I have in inheritance_planner() is certainly not right. It's pretty easy to made the SELECT and UPDATE/DELETE's RT indexes differ with something like: drop table part_t cascade; create table part_t (a int, b int, c int) partition by list (a); create table part_t12 partition of part_t for values in(1,2) partition by list (a); create table part_t12_1 partition of part_t12 for values in(1); create table part_t12_2 partition of part_t12 for values in(2); create table part_t3 partition of part_t for values in(3); create view vw_part_t as select * from part_t; explain analyze update vw_part_t set a = t2.a +0 from part_t t2 where t2.a = vw_part_t.a and vw_part_t.a = (select 1); In this case, the sub-partitioned table changes RT index. I can't just take the RelOptInfo's from the partition_root's simple_rel_array and put them in the correct element in the root's simple_rel_array as they RT indexes stored within also need to be translated. I'll be having another look at this to see what the best fix is going to be. David
