database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-15 19:21:59 +03:00
Code Activity

Expand partitioned table RTEs level by level, without flattening.

Browse Source 
Flattening the partitioning hierarchy at this stage makes various
desirable optimizations difficult.  The original use case for this
patch was partition-wise join, which wants to match up the partitions
in one partitioning hierarchy with those in another such hierarchy.
However, it now seems that it will also be useful in making partition
pruning work using the PartitionDesc rather than constraint exclusion,
because with a flattened expansion, we have no easy way to figure out
which PartitionDescs apply to which leaf tables in a multi-level
partition hierarchy.

As it turns out, we end up creating both rte->inh and !rte->inh RTEs
for each intermediate partitioned table, just as we previously did for
the root table.  This seems unnecessary since the partitioned tables
have no storage and are not scanned.  We might want to go back and
rejigger things so that no partitioned tables (including the parent)
need !rte->inh RTEs, but that seems to require some adjustments not
related to the core purpose of this patch.

Ashutosh Bapat, reviewed by me and by Amit Langote.  Some final
adjustments by me.

Discussion: http://postgr.es/m/CAFjFpRd=1venqLL7oGU=C1dEkuvk2DJgvF+7uKbnPHaum1mvHQ@mail.gmail.com
This commit is contained in:
Robert Haas
2017-09-14 15:41:08 -04:00
parent 0c4b879b74
commit 0a480502b0
9 changed files with 351 additions and 138 deletions
Download Patch File Download Diff File Expand all files Collapse all files

22
src/backend/optimizer/plan/initsplan.c
View File

@ -15,6 +15,7 @@
#include "postgres.h"
#include "catalog/pg_type.h"
#include "catalog/pg_class.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/clauses.h"
#include "optimizer/cost.h"
@ -629,11 +630,28 @@ create_lateral_join_info(PlannerInfo *root)
for (rti = 1; rti < root->simple_rel_array_size; rti++)
{
RelOptInfo *brel = root->simple_rel_array[rti];
RangeTblEntry *brte = root->simple_rte_array[rti];
if (brel == NULL || brel->reloptkind != RELOPT_BASEREL)
if (brel == NULL)
continue;
if (root->simple_rte_array[rti]->inh)
/*
* In the case of table inheritance, the parent RTE is directly linked
* to every child table via an AppendRelInfo. In the case of table
* partitioning, the inheritance hierarchy is expanded one level at a
* time rather than flattened. Therefore, an other member rel that is
* a partitioned table may have children of its own, and must
* therefore be marked with the appropriate lateral info so that those
* children eventually get marked also.
*/
Assert(IS_SIMPLE_REL(brel));
Assert(brte);
if (brel->reloptkind == RELOPT_OTHER_MEMBER_REL &&
(brte->rtekind != RTE_RELATION ||
brte->relkind != RELKIND_PARTITIONED_TABLE))
continue;
if (brte->inh)
{
foreach(lc, root->append_rel_list)
{