postgres/src/include/executor/execPartition.h
Robert Haas 2f17844104 Allow UPDATE to move rows between partitions.
When an UPDATE causes a row to no longer match the partition
constraint, try to move it to a different partition where it does
match the partition constraint.  In essence, the UPDATE is split into
a DELETE from the old partition and an INSERT into the new one.  This
can lead to surprising behavior in concurrency scenarios because
EvalPlanQual rechecks won't work as they normally did; the known
problems are documented.  (There is a pending patch to improve the
situation further, but it needs more review.)

Amit Khandekar, reviewed and tested by Amit Langote, David Rowley,
Rajkumar Raghuwanshi, Dilip Kumar, Amul Sul, Thomas Munro, Álvaro
Herrera, Amit Kapila, and me.  A few final revisions by me.

Discussion: http://postgr.es/m/CAJ3gD9do9o2ccQ7j7+tSgiE1REY65XRiMb=yJO3u3QhyP8EEPQ@mail.gmail.com
2018-01-19 15:33:06 -05:00

120 lines
4.7 KiB
C

/*--------------------------------------------------------------------
* execPartition.h
* POSTGRES partitioning executor interface
*
* Portions Copyright (c) 1996-2018, 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 "catalog/partition.h"
#include "nodes/execnodes.h"
#include "nodes/parsenodes.h"
#include "nodes/plannodes.h"
/*-----------------------
* PartitionDispatch - information about one partitioned table in a partition
* hierarchy required to route a tuple to one of its partitions
*
* reldesc Relation descriptor of the table
* key Partition key information of the table
* keystate Execution state required for expressions in the partition key
* partdesc Partition descriptor of the table
* tupslot A standalone TupleTableSlot initialized with this table's tuple
* descriptor
* tupmap TupleConversionMap to convert from the parent's rowtype to
* this table's rowtype (when extracting the partition key of a
* tuple just before routing it through this table)
* indexes Array with partdesc->nparts members (for details on what
* individual members represent, see how they are set in
* get_partition_dispatch_recurse())
*-----------------------
*/
typedef struct PartitionDispatchData
{
Relation reldesc;
PartitionKey key;
List *keystate; /* list of ExprState */
PartitionDesc partdesc;
TupleTableSlot *tupslot;
TupleConversionMap *tupmap;
int *indexes;
} PartitionDispatchData;
typedef struct PartitionDispatchData *PartitionDispatch;
/*-----------------------
* PartitionTupleRouting - Encapsulates all information required to execute
* tuple-routing between partitions.
*
* partition_dispatch_info Array of PartitionDispatch objects with one
* entry for every partitioned table in the
* partition tree.
* num_dispatch number of partitioned tables in the partition
* tree (= length of partition_dispatch_info[])
* partitions Array of ResultRelInfo* objects with one entry
* for every leaf partition in the partition tree.
* num_partitions Number of leaf partitions in the partition tree
* (= 'partitions' array length)
* parent_child_tupconv_maps Array of TupleConversionMap objects with one
* entry for every leaf partition (required to
* convert tuple from the root table's rowtype to
* a leaf partition's rowtype after tuple routing
* is done)
* child_parent_tupconv_maps Array of TupleConversionMap objects with one
* entry for every leaf partition (required to
* convert an updated tuple from the leaf
* partition's rowtype to the root table's rowtype
* so that tuple routing can be done)
* child_parent_map_not_required Array of bool. True value means that a map is
* determined to be not required for the given
* partition. False means either we haven't yet
* checked if a map is required, or it was
* determined to be required.
* subplan_partition_offsets Integer array ordered by UPDATE subplans. Each
* element of this array has the index into the
* corresponding partition in partitions array.
* partition_tuple_slot TupleTableSlot to be used to manipulate any
* given leaf partition's rowtype after that
* partition is chosen for insertion by
* tuple-routing.
*-----------------------
*/
typedef struct PartitionTupleRouting
{
PartitionDispatch *partition_dispatch_info;
int num_dispatch;
ResultRelInfo **partitions;
int num_partitions;
TupleConversionMap **parent_child_tupconv_maps;
TupleConversionMap **child_parent_tupconv_maps;
bool *child_parent_map_not_required;
int *subplan_partition_offsets;
TupleTableSlot *partition_tuple_slot;
TupleTableSlot *root_tuple_slot;
} PartitionTupleRouting;
extern PartitionTupleRouting *ExecSetupPartitionTupleRouting(ModifyTableState *mtstate,
Relation rel, Index resultRTindex,
EState *estate);
extern int ExecFindPartition(ResultRelInfo *resultRelInfo,
PartitionDispatch *pd,
TupleTableSlot *slot,
EState *estate);
extern void ExecSetupChildParentMapForLeaf(PartitionTupleRouting *proute);
extern TupleConversionMap *TupConvMapForLeaf(PartitionTupleRouting *proute,
ResultRelInfo *rootRelInfo, int leaf_index);
extern HeapTuple ConvertPartitionTupleSlot(TupleConversionMap *map,
HeapTuple tuple,
TupleTableSlot *new_slot,
TupleTableSlot **p_my_slot);
extern void ExecCleanupTupleRouting(PartitionTupleRouting *proute);
#endif /* EXECPARTITION_H */