Horton

Re: why partition pruning doesn't work?

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

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: David Rowley <david.rowley@2ndquadrant.com>
Cc: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>, Dmitry Dolgov <9erthalion6@gmail.com>, Jeff Janes <jeff.janes@gmail.com>, Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>, Pavel Stehule <pavel.stehule@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2018-06-09T21:00:26Z
Lists: pgsql-hackers 
I wrote:
> One thing I'm wondering about is why in the world are PartitionPruneInfo
> and its subsidiary struct types declared in primnodes.h?

Oh, and while I'm bitching: it seems like there is hardly any part of
the partitioning code in which the comments aren't desperately in need
of a copy-editing pass.  They are just chock-full of misspellings,
grammar that is faulty enough to make the meaning unclear, and/or
errors of fact.  An example of the latter is the repeated claims that
the basic partitioning functions belong to the planner.  Maybe that
was true at some stage of development; but AFAICS the logic in question
now lives in src/backend/partitioning/, which I would not think is
part of the planner.

			regards, tom lane

Commits

  1. Fix up run-time partition pruning's use of relcache's partition data.

  2. Fix access to just-closed relcache entry.

  3. Improve ExecFindInitialMatchingSubPlans's subplan renumbering logic.

  4. Improve commentary about run-time partition pruning data structures.

  5. Fix run-time partition pruning code to handle NULL values properly.

  6. Assorted cosmetic cleanup of run-time-partition-pruning code.

  7. Relocate partition pruning structs to a saner place.

  8. Improve run-time partition pruning to handle any stable expression.

  9. Support partition pruning at execution time