Files
postgresql/src/include/executor/execPartition.h
Amit Langote cbc127917e Track unpruned relids to avoid processing pruned relations
This commit introduces changes to track unpruned relations explicitly,
making it possible for top-level plan nodes, such as ModifyTable and
LockRows, to avoid processing partitions pruned during initial
pruning.  Scan-level nodes, such as Append and MergeAppend, already
avoid the unnecessary processing by accessing partition pruning
results directly via part_prune_index. In contrast, top-level nodes
cannot access pruning results directly and need to determine which
partitions remain unpruned.

To address this, this commit introduces a new bitmapset field,
es_unpruned_relids, which the executor uses to track the set of
unpruned relations.  This field is referenced during plan
initialization to skip initializing certain nodes for pruned
partitions. It is initialized with PlannedStmt.unprunableRelids,
a new field that the planner populates with RT indexes of relations
that cannot be pruned during runtime pruning. These include relations
not subject to partition pruning and those required for execution
regardless of pruning.

PlannedStmt.unprunableRelids is computed during set_plan_refs() by
removing the RT indexes of runtime-prunable relations, identified
from PartitionPruneInfos, from the full set of relation RT indexes.
ExecDoInitialPruning() then updates es_unpruned_relids by adding
partitions that survive initial pruning.

To support this, PartitionedRelPruneInfo and PartitionedRelPruningData
now include a leafpart_rti_map[] array that maps partition indexes to
their corresponding RT indexes. The former is used in set_plan_refs()
when constructing unprunableRelids, while the latter is used in
ExecDoInitialPruning() to convert partition indexes returned by
get_matching_partitions() into RT indexes, which are then added to
es_unpruned_relids.

These changes make it possible for ModifyTable and LockRows nodes to
process only relations that remain unpruned after initial pruning.
ExecInitModifyTable() trims lists, such as resultRelations,
withCheckOptionLists, returningLists, and updateColnosLists, to
consider only unpruned partitions. It also creates ResultRelInfo
structs only for these partitions. Similarly, child RowMarks for
pruned relations are skipped.

By avoiding unnecessary initialization of structures for pruned
partitions, these changes improve the performance of updates and
deletes on partitioned tables during initial runtime pruning.

Due to ExecInitModifyTable() changes as described above, EXPLAIN on a
plan for UPDATE and DELETE that uses runtime initial pruning no longer
lists partitions pruned during initial pruning.

Reviewed-by: Robert Haas <robertmhaas@gmail.com> (earlier versions)
Reviewed-by: Tomas Vondra <tomas@vondra.me>
Discussion: https://postgr.es/m/CA+HiwqFGkMSge6TgC9KQzde0ohpAycLQuV7ooitEEpbKB0O_mg@mail.gmail.com
2025-02-07 17:15:09 +09:00

144 lines
5.6 KiB
C

/*--------------------------------------------------------------------
* execPartition.h
* POSTGRES partitioning executor interface
*
* Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* src/include/executor/execPartition.h
*--------------------------------------------------------------------
*/
#ifndef EXECPARTITION_H
#define EXECPARTITION_H
#include "nodes/execnodes.h"
#include "nodes/parsenodes.h"
#include "nodes/plannodes.h"
#include "partitioning/partprune.h"
/* See execPartition.c for the definitions. */
typedef struct PartitionDispatchData *PartitionDispatch;
typedef struct PartitionTupleRouting PartitionTupleRouting;
extern PartitionTupleRouting *ExecSetupPartitionTupleRouting(EState *estate,
Relation rel);
extern ResultRelInfo *ExecFindPartition(ModifyTableState *mtstate,
ResultRelInfo *rootResultRelInfo,
PartitionTupleRouting *proute,
TupleTableSlot *slot,
EState *estate);
extern void ExecCleanupTupleRouting(ModifyTableState *mtstate,
PartitionTupleRouting *proute);
/*
* PartitionedRelPruningData - Per-partitioned-table data for run-time pruning
* of partitions. For a multilevel partitioned table, we have one of these
* for the topmost partition plus one for each non-leaf child partition.
*
* subplan_map[] and subpart_map[] have the same definitions as in
* PartitionedRelPruneInfo (see plannodes.h); though note that here,
* subpart_map contains indexes into PartitionPruningData.partrelprunedata[].
*
* partrel Partitioned table Relation; obtained by
* ExecGetRangeTableRelation(estate, rti), where
* rti is PartitionedRelPruneInfo.rtindex.
* nparts Length of subplan_map[] and subpart_map[].
* subplan_map Subplan index by partition index, or -1.
* subpart_map Subpart index by partition index, or -1.
* leafpart_rti_map RT index by partition index, or 0.
* present_parts A Bitmapset of the partition indexes that we
* have subplans or subparts for.
* initial_pruning_steps List of PartitionPruneSteps used to
* perform executor startup pruning.
* exec_pruning_steps List of PartitionPruneSteps used to
* perform per-scan pruning.
* initial_context If initial_pruning_steps isn't NIL, contains
* the details needed to execute those steps.
* exec_context If exec_pruning_steps isn't NIL, contains
* the details needed to execute those steps.
*/
typedef struct PartitionedRelPruningData
{
Relation partrel;
int nparts;
int *subplan_map;
int *subpart_map;
int *leafpart_rti_map;
Bitmapset *present_parts;
List *initial_pruning_steps;
List *exec_pruning_steps;
PartitionPruneContext initial_context;
PartitionPruneContext exec_context;
} PartitionedRelPruningData;
/*
* PartitionPruningData - Holds all the run-time pruning information for
* a single partitioning hierarchy containing one or more partitions.
* partrelprunedata[] is an array ordered such that parents appear before
* their children; in particular, the first entry is the topmost partition,
* which was actually named in the SQL query.
*/
typedef struct PartitionPruningData
{
int num_partrelprunedata; /* number of array entries */
PartitionedRelPruningData partrelprunedata[FLEXIBLE_ARRAY_MEMBER];
} PartitionPruningData;
/*
* PartitionPruneState - State object required for plan nodes to perform
* run-time partition pruning.
*
* This struct can be attached to plan types which support arbitrary Lists of
* subplans containing partitions, to allow subplans to be eliminated due to
* the clauses being unable to match to any tuple that the subplan could
* possibly produce.
*
* econtext Standalone ExprContext to evaluate expressions in
* the pruning steps
* execparamids Contains paramids of PARAM_EXEC Params found within
* any of the partprunedata structs. Pruning must be
* done again each time the value of one of these
* parameters changes.
* other_subplans Contains indexes of subplans that don't belong to any
* "partprunedata", e.g UNION ALL children that are not
* partitioned tables, or a partitioned table that the
* planner deemed run-time pruning to be useless for.
* These must not be pruned.
* prune_context A short-lived memory context in which to execute the
* partition pruning functions.
* do_initial_prune true if pruning should be performed during executor
* startup (at any hierarchy level).
* do_exec_prune true if pruning should be performed during
* executor run (at any hierarchy level).
* num_partprunedata Number of items in "partprunedata" array.
* partprunedata Array of PartitionPruningData pointers for the plan's
* partitioned relation(s), one for each partitioning
* hierarchy that requires run-time pruning.
*/
typedef struct PartitionPruneState
{
ExprContext *econtext;
Bitmapset *execparamids;
Bitmapset *other_subplans;
MemoryContext prune_context;
bool do_initial_prune;
bool do_exec_prune;
int num_partprunedata;
PartitionPruningData *partprunedata[FLEXIBLE_ARRAY_MEMBER];
} PartitionPruneState;
extern void ExecDoInitialPruning(EState *estate);
extern PartitionPruneState *ExecInitPartitionExecPruning(PlanState *planstate,
int n_total_subplans,
int part_prune_index,
Bitmapset *relids,
Bitmapset **initially_valid_subplans);
extern Bitmapset *ExecFindMatchingSubPlans(PartitionPruneState *prunestate,
bool initial_prune,
Bitmapset **validsubplan_rtis);
#endif /* EXECPARTITION_H */