Horton

Re: [HACKERS] path toward faster partition pruning

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

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From: David Rowley <david.rowley@2ndquadrant.com>
To: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>
Cc: Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>, Rajkumar Raghuwanshi <rajkumar.raghuwanshi@enterprisedb.com>, Robert Haas <robertmhaas@gmail.com>, Dilip Kumar <dilipbalaut@gmail.com>, Beena Emerson <memissemerson@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2017-12-19T04:36:44Z
Lists: pgsql-hackers 
On 12 December 2017 at 22:13, Amit Langote
<Langote_Amit_f8@lab.ntt.co.jp> wrote:
> Attached updated patches.

Hi Amit,

I'm sorry to say this is another micro review per code I'm stumbling
over when looking at the run-time partition pruning stuff.

1. In get_partitions_from_clauses_recurse(), since you're assigning
the result to the first input, the following should use
bms_add_members and not bms_union. The logical end result is the same,
but using bms_union means a wasted palloc and a small memory leak
within the memory context.

/*
* Partition sets obtained from mutually-disjunctive clauses are
* combined using set union.
*/
or_partset = bms_union(or_partset, arg_partset);


2. Also in get_partitions_from_clauses_recurse(), it might also be
worth putting in a bms_free(or_partset) after:

/*
* Partition sets obtained from mutually-conjunctive clauses are
* combined using set intersection.
*/
result = bms_intersect(result, or_partset);

Also, instead of using bms_intersect here, would it be better to do:

result = bms_del_members(result, or_partset); ?

That way you don't do a bms_copy and leak member for each OR branch
since bms_intersect also does a bms_copy()

The resulting set could end up with a few more trailing 0 words than
what you have now, but it to be a better idea not allocate a new set
each time.

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

Commits

  1. Fix assorted partition pruning bugs

  2. Make gen_partprune_steps static

  3. Remove useless 'default' clause

  4. Reorganize partitioning code

  5. Use custom hash opclass for hash partition pruning

  6. Blindly attempt to fix sepgsql tests broken due to 9fdb675fc5.

  7. Attempt to fix endianess issues in new hash partition test.

  8. Faster partition pruning

  9. For partitionwise join, match on partcollation, not parttypcoll.

  10. Revise API for partition bound search functions.

  11. Revise API for partition_rbound_cmp/partition_rbound_datum_cmp.

  12. Fix possible crash in partition-wise join.

  13. Refactor code for partition bound searching

  14. New C function: bms_add_range

  15. Add extensive tests for partition pruning.

  16. Add null test to partition constraint for default range partitions.

  17. Remove BufFile's isTemp flag.

  18. Make OWNER TO subcommand mention consistent

  19. Fix index matching for operators with mixed collatable/noncollatable inputs.