postgres/src/include/partitioning/partbounds.h

/*-------------------------------------------------------------------------
 *
 * partbounds.h
 *
 * Copyright (c) 2007-2021, PostgreSQL Global Development Group
 *
 * src/include/partitioning/partbounds.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef PARTBOUNDS_H
#define PARTBOUNDS_H

#include "fmgr.h"
#include "parser/parse_node.h"
#include "partitioning/partdefs.h"

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


/*
 * PartitionBoundInfoData encapsulates a set of partition bounds. It is
 * usually associated with partitioned tables as part of its partition
 * descriptor, but may also be used to represent a virtual partitioned
 * table such as a partitioned joinrel within the planner.
 *
 * A list partition datum that is known to be NULL is never put into the
 * datums array. Instead, it is tracked using the null_index field.
 *
 * In the case of range partitioning, ndatums will typically be far less than
 * 2 * nparts, because a partition's upper bound and the next partition's lower
 * bound are the same in most common cases, and we only store one of them (the
 * upper bound).  In case of hash partitioning, ndatums will be the same as the
 * number of partitions.
 *
 * For range and list partitioned tables, datums is an array of datum-tuples
 * with key->partnatts datums each.  For hash partitioned tables, it is an array
 * of datum-tuples with 2 datums, modulus and remainder, corresponding to a
 * given partition.
 *
 * The datums in datums array are arranged in increasing order as defined by
 * functions qsort_partition_rbound_cmp(), qsort_partition_list_value_cmp() and
 * qsort_partition_hbound_cmp() for range, list and hash partitioned tables
 * respectively. For range and list partitions this simply means that the
 * datums in the datums array are arranged in increasing order as defined by
 * the partition key's operator classes and collations.
 *
 * In the case of list partitioning, the indexes array stores one entry for
 * each datum-array entry, which is the index of the partition that accepts
 * rows matching that datum.  So nindexes == ndatums.
 *
 * In the case of range partitioning, the indexes array stores one entry per
 * distinct range datum, which is the index of the partition for which that
 * datum is an upper bound (or -1 for a "gap" that has no partition).  It is
 * convenient to have an extra -1 entry representing values above the last
 * range datum, so nindexes == ndatums + 1.
 *
 * In the case of hash partitioning, the number of entries in the indexes
 * array is the same as the greatest modulus amongst all partitions (which
 * is a multiple of all partition moduli), so nindexes == greatest modulus.
 * The indexes array is indexed according to the hash key's remainder modulo
 * the greatest modulus, and it contains either the partition index accepting
 * that remainder, or -1 if there is no partition for that remainder.
 */
typedef struct PartitionBoundInfoData
{
	char		strategy;		/* hash, list or range? */
	int			ndatums;		/* Length of the datums[] array */
	Datum	  **datums;
	PartitionRangeDatumKind **kind; /* The kind of each range bound datum;
									 * NULL for hash and list partitioned
									 * tables */
	int			nindexes;		/* Length of the indexes[] array */
	int		   *indexes;		/* Partition indexes */
	int			null_index;		/* Index of the null-accepting partition; -1
								 * if there isn't one */
	int			default_index;	/* Index of the default partition; -1 if there
								 * isn't one */
} PartitionBoundInfoData;

#define partition_bound_accepts_nulls(bi) ((bi)->null_index != -1)
#define partition_bound_has_default(bi) ((bi)->default_index != -1)

extern int	get_hash_partition_greatest_modulus(PartitionBoundInfo b);
extern uint64 compute_partition_hash_value(int partnatts, FmgrInfo *partsupfunc,
										   Oid *partcollation,
										   Datum *values, bool *isnull);
extern List *get_qual_from_partbound(Relation rel, Relation parent,
									 PartitionBoundSpec *spec);
extern PartitionBoundInfo partition_bounds_create(PartitionBoundSpec **boundspecs,
												  int nparts, PartitionKey key, int **mapping);
extern bool partition_bounds_equal(int partnatts, int16 *parttyplen,
								   bool *parttypbyval, PartitionBoundInfo b1,
								   PartitionBoundInfo b2);
extern PartitionBoundInfo partition_bounds_copy(PartitionBoundInfo src,
												PartitionKey key);
extern PartitionBoundInfo partition_bounds_merge(int partnatts,
												 FmgrInfo *partsupfunc,
												 Oid *partcollation,
												 struct RelOptInfo *outer_rel,
												 struct RelOptInfo *inner_rel,
												 JoinType jointype,
												 List **outer_parts,
												 List **inner_parts);
extern bool partitions_are_ordered(PartitionBoundInfo boundinfo, int nparts);
extern void check_new_partition_bound(char *relname, Relation parent,
									  PartitionBoundSpec *spec,
									  ParseState *pstate);
extern void check_default_partition_contents(Relation parent,
											 Relation defaultRel,
											 PartitionBoundSpec *new_spec);

extern int32 partition_rbound_datum_cmp(FmgrInfo *partsupfunc,
										Oid *partcollation,
										Datum *rb_datums, PartitionRangeDatumKind *rb_kind,
										Datum *tuple_datums, int n_tuple_datums);
extern int	partition_list_bsearch(FmgrInfo *partsupfunc,
								   Oid *partcollation,
								   PartitionBoundInfo boundinfo,
								   Datum value, bool *is_equal);
extern int	partition_range_datum_bsearch(FmgrInfo *partsupfunc,
										  Oid *partcollation,
										  PartitionBoundInfo boundinfo,
										  int nvalues, Datum *values, bool *is_equal);
extern int	partition_hash_bsearch(PartitionBoundInfo boundinfo,
								   int modulus, int remainder);

#endif							/* PARTBOUNDS_H */