Re: executor relation handling

Amit Langote <Langote_Amit_f8(at)lab(dot)ntt(dot)co(dot)jp> writes:
> On 2018/10/08 3:55, Tom Lane wrote:
>> I didn't like the idea of unifying ModifyTable.nominalRelation with
>> the partition root info. Those fields serve different masters ---
>> nominalRelation, at least in its original intent, is only meant for
>> use of EXPLAIN and might have nothing to do with what happens at
>> execution. So even though unifying them would work today, we might
>> regret it down the line. Instead I left that field alone and added
>> a separate rootRelation field to carry the partition root RT index,
>> which ends up being the same number of fields anyway since we don't
>> need a flag for is-the-nominal-relation-a-partition-root.

> Thanks for pushing that. I'd also named it 'rootRelation' in my original
> patch before David had objected to calling it that, because a command may
> not specify the "actual" root of a partition tree; it could be a non-root
> partitioned table. He'd suggested 'partitionedTarget' for the new field
> [1], stressing the "target" part. Maybe, 'rootRelation' isn't too
> confusing though.

Well, it's the root so far as the current query is concerned --- we do not
take any semantic account of partitioning levels that might exist above
the table named in the query, do we?

regards, tom lane