codekingpro/portable-devtools

1/*-------------------------------------------------------------------------2 *3 * selfuncs.h4 *	  Selectivity functions for standard operators, and assorted5 *	  infrastructure for selectivity and cost estimation.6 *7 *8 * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group9 * Portions Copyright (c) 1994, Regents of the University of California10 *11 * src/include/utils/selfuncs.h12 *13 *-------------------------------------------------------------------------14 */15#ifndef SELFUNCS_H16#define SELFUNCS_H17 18#include "access/htup.h"19#include "fmgr.h"20#include "nodes/pathnodes.h"21 22 23/*24 * Note: the default selectivity estimates are not chosen entirely at random.25 * We want them to be small enough to ensure that indexscans will be used if26 * available, for typical table densities of ~100 tuples/page.  Thus, for27 * example, 0.01 is not quite small enough, since that makes it appear that28 * nearly all pages will be hit anyway.  Also, since we sometimes estimate29 * eqsel as 1/num_distinct, we probably want DEFAULT_NUM_DISTINCT to equal30 * 1/DEFAULT_EQ_SEL.31 */32 33/* default selectivity estimate for equalities such as "A = b" */34#define DEFAULT_EQ_SEL	0.00535 36/* default selectivity estimate for inequalities such as "A < b" */37#define DEFAULT_INEQ_SEL  0.333333333333333338 39/* default selectivity estimate for range inequalities "A > b AND A < c" */40#define DEFAULT_RANGE_INEQ_SEL	0.00541 42/* default selectivity estimate for multirange inequalities "A > b AND A < c" */43#define DEFAULT_MULTIRANGE_INEQ_SEL	0.00544 45/* default selectivity estimate for pattern-match operators such as LIKE */46#define DEFAULT_MATCH_SEL	0.00547 48/* default selectivity estimate for other matching operators */49#define DEFAULT_MATCHING_SEL	0.01050 51/* default number of distinct values in a table */52#define DEFAULT_NUM_DISTINCT  20053 54/* default selectivity estimate for boolean and null test nodes */55#define DEFAULT_UNK_SEL			0.00556#define DEFAULT_NOT_UNK_SEL		(1.0 - DEFAULT_UNK_SEL)57 58 59/*60 * Clamp a computed probability estimate (which may suffer from roundoff or61 * estimation errors) to valid range.  Argument must be a float variable.62 */63#define CLAMP_PROBABILITY(p) \64	do { \65		if (p < 0.0) \66			p = 0.0; \67		else if (p > 1.0) \68			p = 1.0; \69	} while (0)70 71/*72 * A set of flags which some selectivity estimation functions can pass back to73 * callers to provide further details about some assumptions which were made74 * during the estimation.75 */76#define SELFLAG_USED_DEFAULT		(1 << 0)	/* Estimation fell back on one77												 * of the DEFAULTs as defined78												 * above. */79 80typedef struct EstimationInfo81{82	uint32		flags;			/* Flags, as defined above to mark special83								 * properties of the estimation. */84} EstimationInfo;85 86/* Return data from examine_variable and friends */87typedef struct VariableStatData88{89	Node	   *var;			/* the Var or expression tree */90	RelOptInfo *rel;			/* Relation, or NULL if not identifiable */91	HeapTuple	statsTuple;		/* pg_statistic tuple, or NULL if none */92	/* NB: if statsTuple!=NULL, it must be freed when caller is done */93	void		(*freefunc) (HeapTuple tuple);	/* how to free statsTuple */94	Oid			vartype;		/* exposed type of expression */95	Oid			atttype;		/* actual type (after stripping relabel) */96	int32		atttypmod;		/* actual typmod (after stripping relabel) */97	bool		isunique;		/* matches unique index or DISTINCT clause */98	bool		acl_ok;			/* result of ACL check on table or column */99} VariableStatData;100 101#define ReleaseVariableStats(vardata)  \102	do { \103		if (HeapTupleIsValid((vardata).statsTuple)) \104			(vardata).freefunc((vardata).statsTuple); \105	} while(0)106 107 108/*109 * genericcostestimate is a general-purpose estimator that can be used for110 * most index types.  In some cases we use genericcostestimate as the base111 * code and then incorporate additional index-type-specific knowledge in112 * the type-specific calling function.  To avoid code duplication, we make113 * genericcostestimate return a number of intermediate values as well as114 * its preliminary estimates of the output cost values.  The GenericCosts115 * struct includes all these values.116 *117 * Callers should initialize all fields of GenericCosts to zero.  In addition,118 * they can set numIndexTuples to some positive value if they have a better119 * than default way of estimating the number of leaf index tuples visited.120 */121typedef struct122{123	/* These are the values the cost estimator must return to the planner */124	Cost		indexStartupCost;	/* index-related startup cost */125	Cost		indexTotalCost; /* total index-related scan cost */126	Selectivity indexSelectivity;	/* selectivity of index */127	double		indexCorrelation;	/* order correlation of index */128 129	/* Intermediate values we obtain along the way */130	double		numIndexPages;	/* number of leaf pages visited */131	double		numIndexTuples; /* number of leaf tuples visited */132	double		spc_random_page_cost;	/* relevant random_page_cost value */133	double		num_sa_scans;	/* # indexscans from ScalarArrayOpExprs */134} GenericCosts;135 136/* Hooks for plugins to get control when we ask for stats */137typedef bool (*get_relation_stats_hook_type) (PlannerInfo *root,138											  RangeTblEntry *rte,139											  AttrNumber attnum,140											  VariableStatData *vardata);141extern PGDLLIMPORT get_relation_stats_hook_type get_relation_stats_hook;142typedef bool (*get_index_stats_hook_type) (PlannerInfo *root,143										   Oid indexOid,144										   AttrNumber indexattnum,145										   VariableStatData *vardata);146extern PGDLLIMPORT get_index_stats_hook_type get_index_stats_hook;147 148/* Functions in selfuncs.c */149 150extern void examine_variable(PlannerInfo *root, Node *node, int varRelid,151							 VariableStatData *vardata);152extern bool statistic_proc_security_check(VariableStatData *vardata, Oid func_oid);153extern bool get_restriction_variable(PlannerInfo *root, List *args,154									 int varRelid,155									 VariableStatData *vardata, Node **other,156									 bool *varonleft);157extern void get_join_variables(PlannerInfo *root, List *args,158							   SpecialJoinInfo *sjinfo,159							   VariableStatData *vardata1,160							   VariableStatData *vardata2,161							   bool *join_is_reversed);162extern double get_variable_numdistinct(VariableStatData *vardata,163									   bool *isdefault);164extern double mcv_selectivity(VariableStatData *vardata,165							  FmgrInfo *opproc, Oid collation,166							  Datum constval, bool varonleft,167							  double *sumcommonp);168extern double histogram_selectivity(VariableStatData *vardata,169									FmgrInfo *opproc, Oid collation,170									Datum constval, bool varonleft,171									int min_hist_size, int n_skip,172									int *hist_size);173extern double generic_restriction_selectivity(PlannerInfo *root,174											  Oid oproid, Oid collation,175											  List *args, int varRelid,176											  double default_selectivity);177extern double ineq_histogram_selectivity(PlannerInfo *root,178										 VariableStatData *vardata,179										 Oid opoid, FmgrInfo *opproc,180										 bool isgt, bool iseq,181										 Oid collation,182										 Datum constval, Oid consttype);183extern double var_eq_const(VariableStatData *vardata,184						   Oid oproid, Oid collation,185						   Datum constval, bool constisnull,186						   bool varonleft, bool negate);187extern double var_eq_non_const(VariableStatData *vardata,188							   Oid oproid, Oid collation,189							   Node *other,190							   bool varonleft, bool negate);191 192extern Selectivity boolvarsel(PlannerInfo *root, Node *arg, int varRelid);193extern Selectivity booltestsel(PlannerInfo *root, BoolTestType booltesttype,194							   Node *arg, int varRelid,195							   JoinType jointype, SpecialJoinInfo *sjinfo);196extern Selectivity nulltestsel(PlannerInfo *root, NullTestType nulltesttype,197							   Node *arg, int varRelid,198							   JoinType jointype, SpecialJoinInfo *sjinfo);199extern Selectivity scalararraysel(PlannerInfo *root,200								  ScalarArrayOpExpr *clause,201								  bool is_join_clause,202								  int varRelid, JoinType jointype, SpecialJoinInfo *sjinfo);203extern int	estimate_array_length(Node *arrayexpr);204extern Selectivity rowcomparesel(PlannerInfo *root,205								 RowCompareExpr *clause,206								 int varRelid, JoinType jointype, SpecialJoinInfo *sjinfo);207 208extern void mergejoinscansel(PlannerInfo *root, Node *clause,209							 Oid opfamily, int strategy, bool nulls_first,210							 Selectivity *leftstart, Selectivity *leftend,211							 Selectivity *rightstart, Selectivity *rightend);212 213extern double estimate_num_groups(PlannerInfo *root, List *groupExprs,214								  double input_rows, List **pgset,215								  EstimationInfo *estinfo);216 217extern void estimate_hash_bucket_stats(PlannerInfo *root,218									   Node *hashkey, double nbuckets,219									   Selectivity *mcv_freq,220									   Selectivity *bucketsize_frac);221extern double estimate_hashagg_tablesize(PlannerInfo *root, Path *path,222										 const AggClauseCosts *agg_costs,223										 double dNumGroups);224 225extern List *get_quals_from_indexclauses(List *indexclauses);226extern Cost index_other_operands_eval_cost(PlannerInfo *root,227										   List *indexquals);228extern List *add_predicate_to_index_quals(IndexOptInfo *index,229										  List *indexQuals);230extern void genericcostestimate(PlannerInfo *root, IndexPath *path,231								double loop_count,232								GenericCosts *costs);233 234/* Functions in array_selfuncs.c */235 236extern Selectivity scalararraysel_containment(PlannerInfo *root,237											  Node *leftop, Node *rightop,238											  Oid elemtype, bool isEquality, bool useOr,239											  int varRelid);240 241#endif							/* SELFUNCS_H */242