| /*------------------------------------------------------------------------- |
| * |
| * selfuncs.h |
| * Selectivity functions and index cost estimation functions for |
| * standard operators and index access methods. |
| * |
| * |
| * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group |
| * Portions Copyright (c) 1994, Regents of the University of California |
| * |
| * $PostgreSQL: pgsql/src/include/utils/selfuncs.h,v 1.36.2.1 2007/08/31 23:35:30 tgl Exp $ |
| * |
| *------------------------------------------------------------------------- |
| */ |
| #ifndef SELFUNCS_H |
| #define SELFUNCS_H |
| |
| #include "fmgr.h" |
| #include "access/htup.h" |
| #include "catalog/catquery.h" |
| #include "nodes/relation.h" |
| |
| |
| /* |
| * Note: the default selectivity estimates are not chosen entirely at random. |
| * We want them to be small enough to ensure that indexscans will be used if |
| * available, for typical table densities of ~100 tuples/page. Thus, for |
| * example, 0.01 is not quite small enough, since that makes it appear that |
| * nearly all pages will be hit anyway. Also, since we sometimes estimate |
| * eqsel as 1/num_distinct, we probably want DEFAULT_NUM_DISTINCT to equal |
| * 1/DEFAULT_EQ_SEL. |
| */ |
| |
| /* default number of distinct values in a table */ |
| #define DEFAULT_NUM_DISTINCT 1000 /*CDB*/ |
| |
| /* default selectivity estimate for equalities such as "A = b" */ |
| #define DEFAULT_EQ_SEL (1.0 / DEFAULT_NUM_DISTINCT) /*CDB*/ |
| |
| /* default selectivity estimate for inequalities such as "A < b" */ |
| #define DEFAULT_INEQ_SEL 0.3333333333333333 |
| |
| /* default selectivity estimate for range inequalities "A > b AND A < c" */ |
| #define DEFAULT_RANGE_INEQ_SEL (10 * DEFAULT_EQ_SEL) /*CDB*/ |
| |
| /* default selectivity estimate for pattern-match operators such as LIKE */ |
| #define DEFAULT_MATCH_SEL (50 * DEFAULT_EQ_SEL) /*CDB*/ |
| |
| /* default selectivity estimate for boolean and null test nodes */ |
| #define DEFAULT_UNK_SEL DEFAULT_EQ_SEL /*CDB*/ |
| #define DEFAULT_NOT_UNK_SEL (1.0 - DEFAULT_UNK_SEL) |
| |
| |
| /* |
| * Clamp a computed probability estimate (which may suffer from roundoff or |
| * estimation errors) to valid range. Argument must be a float variable. |
| */ |
| #define CLAMP_PROBABILITY(p) \ |
| do { \ |
| if (p < 0.0) \ |
| p = 0.0; \ |
| else if (p > 1.0) \ |
| p = 1.0; \ |
| } while (0) |
| |
| |
| /* Return data from examine_variable and friends */ |
| typedef struct VariableStatData |
| { |
| Node *var; /* the Var or expression tree */ |
| RelOptInfo *rel; /* Relation, or NULL if not identifiable */ |
| cqContext *statscqCtx; /* pg_statistic cqctx, or NULL if none */ |
| /* NB: if statsTuple!=NULL, it must be freed when caller is done */ |
| double numdistinctFromPrimaryKey; /* this is the numdistinct as estimated from the primary key relation. If this is < 0, then it is ignored. */ |
| Oid vartype; /* exposed type of expression */ |
| Oid atttype; /* type to pass to get_attstatsslot */ |
| int32 atttypmod; /* typmod to pass to get_attstatsslot */ |
| bool isunique; /* true if matched to a unique index */ |
| } VariableStatData; |
| |
| /* get the pg_statistic tuple, or NULL if none */ |
| #define getStatsTuple(vardata) \ |
| (((NULL != (vardata)) && (NULL != (vardata)->statscqCtx)) ? \ |
| caql_get_current((vardata)->statscqCtx) : NULL) |
| |
| typedef enum |
| { |
| Pattern_Type_Like, Pattern_Type_Like_IC, |
| Pattern_Type_Regex, Pattern_Type_Regex_IC |
| } Pattern_Type; |
| |
| typedef enum |
| { |
| Pattern_Prefix_None, Pattern_Prefix_Partial, Pattern_Prefix_Exact |
| } Pattern_Prefix_Status; |
| |
| |
| /* selfuncs.c */ |
| |
| extern void examine_variable(PlannerInfo *root, Node *node, int varRelid, |
| VariableStatData *vardata); |
| extern void ReleaseVariableStats(VariableStatData vardata); |
| extern bool get_restriction_variable(PlannerInfo *root, List *args, |
| int varRelid, |
| VariableStatData *vardata, Node **other, |
| bool *varonleft); |
| extern void get_join_variables(PlannerInfo *root, List *args, |
| VariableStatData *vardata1, |
| VariableStatData *vardata2); |
| extern double get_variable_numdistinct(VariableStatData *vardata); |
| extern double mcv_selectivity(VariableStatData *vardata, FmgrInfo *opproc, |
| Datum constval, bool varonleft, |
| double *sumcommonp); |
| extern double histogram_selectivity(VariableStatData *vardata, FmgrInfo *opproc, |
| Datum constval, bool varonleft, |
| int min_hist_size, int n_skip); |
| extern double convert_timevalue_to_scalar(Datum value, Oid typid); |
| |
| extern Pattern_Prefix_Status pattern_fixed_prefix(Const *patt, |
| Pattern_Type ptype, |
| Const **prefix, |
| Const **rest); |
| extern Const *make_greater_string(const Const *str_const, FmgrInfo *ltproc); |
| |
| extern Datum eqsel(PG_FUNCTION_ARGS); |
| extern Datum neqsel(PG_FUNCTION_ARGS); |
| extern Datum scalarltsel(PG_FUNCTION_ARGS); |
| extern Datum scalargtsel(PG_FUNCTION_ARGS); |
| extern Datum regexeqsel(PG_FUNCTION_ARGS); |
| extern Datum icregexeqsel(PG_FUNCTION_ARGS); |
| extern Datum likesel(PG_FUNCTION_ARGS); |
| extern Datum iclikesel(PG_FUNCTION_ARGS); |
| extern Datum regexnesel(PG_FUNCTION_ARGS); |
| extern Datum icregexnesel(PG_FUNCTION_ARGS); |
| extern Datum nlikesel(PG_FUNCTION_ARGS); |
| extern Datum icnlikesel(PG_FUNCTION_ARGS); |
| |
| extern Datum eqjoinsel(PG_FUNCTION_ARGS); |
| extern Datum neqjoinsel(PG_FUNCTION_ARGS); |
| extern Datum scalarltjoinsel(PG_FUNCTION_ARGS); |
| extern Datum scalargtjoinsel(PG_FUNCTION_ARGS); |
| extern Datum regexeqjoinsel(PG_FUNCTION_ARGS); |
| extern Datum icregexeqjoinsel(PG_FUNCTION_ARGS); |
| extern Datum likejoinsel(PG_FUNCTION_ARGS); |
| extern Datum iclikejoinsel(PG_FUNCTION_ARGS); |
| extern Datum regexnejoinsel(PG_FUNCTION_ARGS); |
| extern Datum icregexnejoinsel(PG_FUNCTION_ARGS); |
| extern Datum nlikejoinsel(PG_FUNCTION_ARGS); |
| extern Datum icnlikejoinsel(PG_FUNCTION_ARGS); |
| |
| extern Selectivity booltestsel(PlannerInfo *root, BoolTestType booltesttype, |
| Node *arg, int varRelid, JoinType jointype); |
| extern Selectivity nulltestsel(PlannerInfo *root, NullTestType nulltesttype, |
| Node *arg, int varRelid, JoinType jointype); |
| extern Selectivity scalararraysel(PlannerInfo *root, |
| ScalarArrayOpExpr *clause, |
| bool is_join_clause, |
| int varRelid, JoinType jointype); |
| extern int estimate_array_length(Node *arrayexpr); |
| extern Selectivity rowcomparesel(PlannerInfo *root, |
| RowCompareExpr *clause, |
| int varRelid, JoinType jointype); |
| |
| extern void mergejoinscansel(PlannerInfo *root, Node *clause, |
| Selectivity *leftscan, |
| Selectivity *rightscan); |
| |
| extern double estimate_num_groups(PlannerInfo *root, List *groupExprs, |
| double input_rows); |
| |
| extern Selectivity estimate_hash_bucketsize(PlannerInfo *root, Node *hashkey, |
| double nbuckets); |
| |
| extern Datum btcostestimate(PG_FUNCTION_ARGS); |
| extern Datum hashcostestimate(PG_FUNCTION_ARGS); |
| extern Datum gistcostestimate(PG_FUNCTION_ARGS); |
| extern Datum gincostestimate(PG_FUNCTION_ARGS); |
| extern Datum bmcostestimate(PG_FUNCTION_ARGS); |
| |
| #endif /* SELFUNCS_H */ |
