Horton

Re: [HACKERS] Runtime Partition Pruning

David Rowley <david.rowley@2ndquadrant.com>

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From: David Rowley <david.rowley@2ndquadrant.com>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Amit Langote <amitlangote09@gmail.com>, Andres Freund <andres@anarazel.de>, Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>, Jesper Pedersen <jesper.pedersen@redhat.com>, Rajkumar Raghuwanshi <rajkumar.raghuwanshi@enterprisedb.com>, Beena Emerson <memissemerson@gmail.com>, Robert Haas <robertmhaas@gmail.com>, amul sul <sulamul@gmail.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>, Dilip Kumar <dilipbalaut@gmail.com>
Date: 2018-04-07T12:33:37Z
Lists: pgsql-hackers 
On 8 April 2018 at 00:23, Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:
> I edited it as attached, to 1. avoid mentioning functionality that
> doesn't yet exist, and 2. avoid excessive internal detail (we want a
> high-level overview here), which from experience gets outdated pretty
> quickly.

It's not exactly wrong but:

+ * are turned into a set of "pruning steps", which are then executed to
+ * produce a set of RTIs of partitions whose bounds satisfy the constraints in
+ * the step.  Partitions not in the set are said to have been pruned.

It's only prune_append_rel_partitions which is only used for the
planner's pruning needs that converts the partition indexes to RTIs.
Would it be better to mention that the output is partition indexes?
Maybe:

"which are then executed to produce a set of partition indexes whose
bounds satisfy the constraints in the step. These partition indexes
may then be translated into RTIs", or maybe even not mention the RTIs.

-- 
 David Rowley                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services

Commits

  1. Initialize ExprStates once in run-time partition pruning

  2. Add bms_prev_member function

  3. Support partition pruning at execution time

  4. Document partprune.c a little better

  5. Fix crash in pg_replication_slot_advance

  6. Add parallel-aware hash joins.

  7. Fix typo.

  8. Allow --with-bonjour to work with non-macOS implementations of Bonjour.

  9. Mention need for --no-inc-recursive in rsync command