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: 2017-04-26T16:41:56Z
Lists: pgsql-hackers 
Robert Haas <robertmhaas@gmail.com> writes:
> So this is about a cross-type join,
> not multiple types within a single partitioning hierarchy, as you
> might also gather from the subject line of this thread.

OK, but I still don't understand why any type conversion is needed
in such a case.  The existing join estimators don't try to do that,
for the good and sufficient reasons you and I have already mentioned.
They just apply the given cross-type join operator, and whatever
cross-type selectivity estimator might be associated with it, and
possibly other cross-type operators obtained from the same btree
opfamily.

The minute you get into trying to do any type conversion that is not
mandated by the semantics of the query as written, you're going to
have problems.

			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".