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: Thomas Munro <thomas.munro@enterprisedb.com>, Rafia Sabih <rafia.sabih@enterprisedb.com>, Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>, Rajkumar Raghuwanshi <rajkumar.raghuwanshi@enterprisedb.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2017-09-01T19:10:22Z
Lists: pgsql-hackers

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Here's set of patches rebased on the latest head.

This rebase mainly changes patch 0001, which translates partition
hierarchy into inheritance hierarchy creating AppendRelInfos and
RelOptInfos for partitioned partitions. Because of that, it's not
necessary to record the partitioned partitions in a
PartitionedChildRelInfos::child_rels. The only RTI that goes in there
is the RTI of child RTE which is same as the parent RTE except inh
flag. I tried removing that with a series of changes but it seems that
following code in ExecInitModifyTable() requires it.
1897     /* The root table RT index is at the head of the
partitioned_rels list */
1898     if (node->partitioned_rels)
1899     {
1900         Index       root_rti;
1901         Oid         root_oid;
1902
1903         root_rti = linitial_int(node->partitioned_rels);
1904         root_oid = getrelid(root_rti, estate->es_range_table);
1905         rel = heap_open(root_oid, NoLock);  /* locked by InitPlan */
1906     }
1907     else
1908         rel = mtstate->resultRelInfo->ri_RelationDesc;

I don't know whether we could change this code not to use
PartitionedChildRelInfos::child_rels. Removing
PartitionedChildRelInfos machinary seems like a separate patch.

The last two patches implement the advanced partition matching
algorithm and are here in this set for ready reference. Please use [1]
for discussing/reviewing those.

[1] https://www.postgresql.org/message-id/CAFjFpRdjQvaUEV5DJX3TW6pU5eq54NCkadtxHX2JiJG_GvbrCA@mail.gmail.com
-- 
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.