Horton

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

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>
Cc: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>, Etsuro Fujita <fujita.etsuro@lab.ntt.co.jp>, Thomas Munro <thomas.munro@enterprisedb.com>, Rafia Sabih <rafia.sabih@enterprisedb.com>, Rajkumar Raghuwanshi <rajkumar.raghuwanshi@enterprisedb.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2017-10-03T02:18:11Z
Lists: pgsql-hackers 
On Thu, Sep 21, 2017 at 8:21 AM, Ashutosh Bapat
<ashutosh.bapat@enterprisedb.com> wrote:
> Here's set of rebased patches. The patch with extra tests is not for
> committing. All other patches, except the last one, will need to be
> committed together. The last patch may be committed along with other
> patches or as a separate patch.

In set_append_rel_size, is it necessary to set attr_needed =
bms_copy(rel->attr_needed[index]) rather than just pointing to the
existing value?  If so, perhaps the comments should explain the
reasons.  I would have thought that the values wouldn't change after
this point, in which case it might not be necessary to copy them.

Regarding nomenclature and my previous griping about wisdom, I was
wondering about just calling this a "partition join" like you have in
the regression test.  So the GUC would be enable_partition_join, you'd
have generate_partition_join_paths(), etc.  Basically just delete
"wise" throughout.

The elog(DEBUG3) in try_partition_wise_join() doesn't follow message
style guidelines and I think should just be removed.  It was useful
for development, I'm sure, but it's time for it to go.

+            elog(ERROR, "unrecognized path node type %d", (int) nodeTag(path));

I think we should use the same formulation as elsewhere, namely
"unrecognized node type: %d".  And likewise probably "unexpected join
type: %d".

partition_join_extras.sql has a bunch of whitespace damage, although
it doesn't really matter since, as you say, that's not for commit.

(This is not a full review, just a few thoughts.)

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

Commits

  1. Add test for partitionwise join involving default partition.

  2. Rewrite the code that applies scan/join targets to paths.

  3. Fix code related to partitioning schemes for dropped columns.

  4. Copy information from the relcache instead of pointing to it.

  5. Basic partition-wise join functionality.

  6. Associate partitioning information with each RelOptInfo.

  7. Expand partitioned table RTEs level by level, without flattening.

  8. Set partitioned_rels appropriately when UNION ALL is used.

  9. Remove dedicated B-tree root-split record types.

  10. Assorted preparatory refactoring for partition-wise join.

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

  12. Avoid unnecessary single-child Append nodes.

  13. Revisit handling of UNION ALL subqueries with non-Var output columns.