Horton

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

Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>

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From: Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>
To: Robert Haas <robertmhaas@gmail.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: 2017-10-16T11:33:07Z
Lists: pgsql-hackers

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On Sat, Oct 7, 2017 at 1:04 AM, Robert Haas <robertmhaas@gmail.com> wrote:

>>
>> The fix is to copy the relevant partitioning information from relcache
>> into PartitionSchemeData and RelOptInfo. Here's a quick patch with
>> that fix.
>
> Committed.  I hope that makes things less red rather than more,
> because I'm going to be AFK for a few hours anyway.
>

set_append_rel_size() crashes when it encounters a partitioned table
with a dropped column. Dropped columns do not have any translations
saved in AppendInfo::translated_vars; the corresponding entry is NULL
per make_inh_translation_list().
1802         att = TupleDescAttr(old_tupdesc, old_attno);
1803         if (att->attisdropped)
1804         {
1805             /* Just put NULL into this list entry */
1806             vars = lappend(vars, NULL);
1807             continue;
1808         }

In set_append_rel_size() we try to attr_needed for child tables. While
doing so we try to translate a user attribute number of parent to that
of a child and crash since the translated Var is NULL. Here's patch to
fix the crash. The patch also contains a testcase to test dropped
columns in partitioned table.

Sorry for not noticing this problem earlier.

-- 
Best Wishes,
Ashutosh Bapat
EnterpriseDB Corporation
The Postgres Database 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.