src/include/partitioning/partprune.h

/*-------------------------------------------------------------------------
 *
 * partprune.h
 *	  prototypes for partprune.c
 *
 *
 * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/include/partitioning/partprune.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef PARTPRUNE_H
#define PARTPRUNE_H

#include "nodes/execnodes.h"
#include "partitioning/partdefs.h"

struct PlannerInfo;				/* avoid including pathnodes.h here */
struct RelOptInfo;


/*
 * PartitionPruneContext
 *		Stores information needed at runtime for pruning computations
 *		related to a single partitioned table.
 *
 * strategy			Partition strategy, e.g. LIST, RANGE, HASH.
 * partnatts		Number of columns in the partition key.
 * nparts			Number of partitions in this partitioned table.
 * boundinfo		Partition boundary info for the partitioned table.
 * partcollation	Array of partnatts elements, storing the collations of the
 *					partition key columns.
 * partsupfunc		Array of FmgrInfos for the comparison or hashing functions
 *					associated with the partition keys (partnatts elements).
 *					(This points into the partrel's partition key, typically.)
 * stepcmpfuncs		Array of FmgrInfos for the comparison or hashing function
 *					for each pruning step and partition key.
 * ppccontext		Memory context holding this PartitionPruneContext's
 *					subsidiary data, such as the FmgrInfos.
 * planstate		Points to the parent plan node's PlanState when called
 *					during execution; NULL when called from the planner.
 * exprstates		Array of ExprStates, indexed as per PruneCxtStateIdx; one
 *					for each partition key in each pruning step.  Allocated if
 *					planstate is non-NULL, otherwise NULL.
 */
typedef struct PartitionPruneContext
{
	char		strategy;
	int			partnatts;
	int			nparts;
	PartitionBoundInfo boundinfo;
	Oid		   *partcollation;
	FmgrInfo   *partsupfunc;
	FmgrInfo   *stepcmpfuncs;
	MemoryContext ppccontext;
	PlanState  *planstate;
	ExprState **exprstates;
} PartitionPruneContext;

/*
 * PruneCxtStateIdx() computes the correct index into the stepcmpfuncs[]
 * and exprstates[] arrays for step step_id and partition key column keyno.
 * (Note: there is code that assumes the entries for a given step are
 * sequential, so this is not chosen freely.)
 */
#define PruneCxtStateIdx(partnatts, step_id, keyno) \
	((partnatts) * (step_id) + (keyno))

extern PartitionPruneInfo *make_partition_pruneinfo(struct PlannerInfo *root,
													struct RelOptInfo *parentrel,
													List *subpaths,
													List *prunequal);
extern PartitionPruneInfo *make_partition_pruneinfo_ext(struct PlannerInfo *root,
														struct RelOptInfo *parentrel,
														List *subpaths,
														List *prunequal, Bitmapset *available_relids);
extern Bitmapset *prune_append_rel_partitions(struct RelOptInfo *rel);
extern Bitmapset *get_matching_partitions(PartitionPruneContext *context,
										  List *pruning_steps);

#endif							/* PARTPRUNE_H */