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/*-------------------------------------------------------------------------
*
* statistics.h
* Extended statistics and selectivity estimation functions.
*
* Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/statistics/statistics.h
*
*-------------------------------------------------------------------------
*/
#ifndef STATISTICS_H
#define STATISTICS_H
#include "commands/vacuum.h"
#include "nodes/relation.h"
#define STATS_MAX_DIMENSIONS 8 /* max number of attributes */
/* Multivariate distinct coefficients */
#define STATS_NDISTINCT_MAGIC 0xA352BFA4 /* struct identifier */
#define STATS_NDISTINCT_TYPE_BASIC 1 /* struct version */
/* MVDistinctItem represents a single combination of columns */
typedef struct MVNDistinctItem
{
double ndistinct; /* ndistinct value for this combination */
Bitmapset *attrs; /* attr numbers of items */
} MVNDistinctItem;
/* size of the struct, excluding attribute list */
#define SizeOfMVNDistinctItem \
(offsetof(MVNDistinctItem, ndistinct) + sizeof(double))
/* A MVNDistinct object, comprising all possible combinations of columns */
typedef struct MVNDistinct
{
uint32 magic; /* magic constant marker */
uint32 type; /* type of ndistinct (BASIC) */
uint32 nitems; /* number of items in the statistic */
MVNDistinctItem items[FLEXIBLE_ARRAY_MEMBER];
} MVNDistinct;
/* size of the struct excluding the items array */
#define SizeOfMVNDistinct (offsetof(MVNDistinct, nitems) + sizeof(uint32))
/* size of the struct excluding the items array */
#define SizeOfMVNDistinct (offsetof(MVNDistinct, nitems) + sizeof(uint32))
#define STATS_DEPS_MAGIC 0xB4549A2C /* marks serialized bytea */
#define STATS_DEPS_TYPE_BASIC 1 /* basic dependencies type */
/*
* Functional dependencies, tracking column-level relationships (values
* in one column determine values in another one).
*/
typedef struct MVDependency
{
double degree; /* degree of validity (0-1) */
AttrNumber nattributes; /* number of attributes */
AttrNumber attributes[FLEXIBLE_ARRAY_MEMBER]; /* attribute numbers */
} MVDependency;
/* size of the struct excluding the deps array */
#define SizeOfDependency \
(offsetof(MVDependency, nattributes) + sizeof(AttrNumber))
typedef struct MVDependencies
{
uint32 magic; /* magic constant marker */
uint32 type; /* type of MV Dependencies (BASIC) */
uint32 ndeps; /* number of dependencies */
MVDependency *deps[FLEXIBLE_ARRAY_MEMBER]; /* dependencies */
} MVDependencies;
/* size of the struct excluding the deps array */
#define SizeOfDependencies (offsetof(MVDependencies, ndeps) + sizeof(uint32))
extern MVNDistinct *statext_ndistinct_load(Oid mvoid);
extern MVDependencies *statext_dependencies_load(Oid mvoid);
extern void BuildRelationExtStatistics(Relation onerel, double totalrows,
int numrows, HeapTuple *rows,
int natts, VacAttrStats **vacattrstats);
extern bool statext_is_kind_built(HeapTuple htup, char kind);
extern Selectivity dependencies_clauselist_selectivity(PlannerInfo *root,
List *clauses,
int varRelid,
JoinType jointype,
SpecialJoinInfo *sjinfo,
RelOptInfo *rel,
Bitmapset **estimatedclauses);
extern bool has_stats_of_kind(List *stats, char requiredkind);
extern StatisticExtInfo *choose_best_statistics(List *stats,
Bitmapset *attnums, char requiredkind);
#endif /* STATISTICS_H */
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