Re: executor relation handling - Mailing list pgsql-hackers

From Tom Lane
Subject Re: executor relation handling
Date
Msg-id 22797.1539094061@sss.pgh.pa.us
Whole thread Raw
In response to Re: executor relation handling  (Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>)
Responses Re: executor relation handling  (Amit Langote <amitlangote09@gmail.com>)
List pgsql-hackers
Amit Langote <Langote_Amit_f8@lab.ntt.co.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


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