Horton

Re: Partition-wise join for join between (declaratively) partitioned tables

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>, Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>, Rafia Sabih <rafia.sabih@enterprisedb.com>, Rajkumar Raghuwanshi <rajkumar.raghuwanshi@enterprisedb.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2017-04-20T06:02:07Z
Lists: pgsql-hackers 
Robert Haas <robertmhaas@gmail.com> writes:
> I don't understand why you think that partition-wise join needs any
> new logic here; if this were a non-partitionwise join, we'd similarly
> need to use the correct operator, but the existing code handles that
> just fine.  If the join is performed partition-wise, it should use the
> same operators that would have been used by a non-partitionwise join
> between the same tables.

More to the point, the appropriate operator was chosen by parse analysis.
The planner has *zero* flexibility as to which operator is involved.

BTW, I remain totally mystified as to what people think the semantics of
partitioning ought to be.  Child columns can have a different type from
parent columns?  Really?  Why is this even under discussion?  We don't
allow that in old-school inheritance, and I cannot imagine a rational
argument why partitioning should allow it.

			regards, tom lane

Commits

  1. Basic partition-wise join functionality.

  2. Assorted preparatory refactoring for partition-wise join.

  3. Teach adjust_appendrel_attrs(_multilevel) to do multiple translations.

  4. Stamp 10beta2.

  5. Eat XIDs more efficiently in recovery TAP test.

  6. Abstract logic to allow for multiple kinds of child rels.

  7. Implement SortSupport for macaddr data type

  8. Attempt to stabilize grouping sets regression test plans.

  9. Teach xlogreader to follow timeline switches

  10. Don't scan partitioned tables.

  11. Fix grammar.

  12. postgres_fdw: Push down FULL JOINs with restriction clauses.

  13. Some preliminary refactoring towards partitionwise join.

  14. contrib/amcheck needs RecentGlobalXmin to be PGDLLIMPORT'ified.

  15. Print test parameters like "foo: 123", and results like "foo = 123".