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c7b8998ebb
Change pg_bsd_indent to follow upstream rules for placement of comments
to the right of code, and remove pgindent hack that caused comments
following #endif to not obey the general rule.
Commit e3860ffa4d wasn't actually using
the published version of pg_bsd_indent, but a hacked-up version that
tried to minimize the amount of movement of comments to the right of
code. The situation of interest is where such a comment has to be
moved to the right of its default placement at column 33 because there's
code there. BSD indent has always moved right in units of tab stops
in such cases --- but in the previous incarnation, indent was working
in 8-space tab stops, while now it knows we use 4-space tabs. So the
net result is that in about half the cases, such comments are placed
one tab stop left of before. This is better all around: it leaves
more room on the line for comment text, and it means that in such
cases the comment uniformly starts at the next 4-space tab stop after
the code, rather than sometimes one and sometimes two tabs after.
Also, ensure that comments following #endif are indented the same
as comments following other preprocessor commands such as #else.
That inconsistency turns out to have been self-inflicted damage
from a poorly-thought-through post-indent "fixup" in pgindent.
This patch is much less interesting than the first round of indent
changes, but also bulkier, so I thought it best to separate the effects.
Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org
Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
225 lines
8.3 KiB
C
225 lines
8.3 KiB
C
/*-------------------------------------------------------------------------
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*
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* selfuncs.h
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* Selectivity functions for standard operators, and assorted
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* infrastructure for selectivity and cost estimation.
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*
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*
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* Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/utils/selfuncs.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef SELFUNCS_H
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#define SELFUNCS_H
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#include "fmgr.h"
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#include "access/htup.h"
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#include "nodes/relation.h"
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/*
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* Note: the default selectivity estimates are not chosen entirely at random.
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* We want them to be small enough to ensure that indexscans will be used if
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* available, for typical table densities of ~100 tuples/page. Thus, for
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* example, 0.01 is not quite small enough, since that makes it appear that
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* nearly all pages will be hit anyway. Also, since we sometimes estimate
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* eqsel as 1/num_distinct, we probably want DEFAULT_NUM_DISTINCT to equal
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* 1/DEFAULT_EQ_SEL.
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*/
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/* default selectivity estimate for equalities such as "A = b" */
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#define DEFAULT_EQ_SEL 0.005
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/* default selectivity estimate for inequalities such as "A < b" */
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#define DEFAULT_INEQ_SEL 0.3333333333333333
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/* default selectivity estimate for range inequalities "A > b AND A < c" */
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#define DEFAULT_RANGE_INEQ_SEL 0.005
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/* default selectivity estimate for pattern-match operators such as LIKE */
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#define DEFAULT_MATCH_SEL 0.005
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/* default number of distinct values in a table */
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#define DEFAULT_NUM_DISTINCT 200
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/* default selectivity estimate for boolean and null test nodes */
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#define DEFAULT_UNK_SEL 0.005
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#define DEFAULT_NOT_UNK_SEL (1.0 - DEFAULT_UNK_SEL)
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/*
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* Clamp a computed probability estimate (which may suffer from roundoff or
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* estimation errors) to valid range. Argument must be a float variable.
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*/
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#define CLAMP_PROBABILITY(p) \
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do { \
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if (p < 0.0) \
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p = 0.0; \
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else if (p > 1.0) \
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p = 1.0; \
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} while (0)
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/* Return data from examine_variable and friends */
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typedef struct VariableStatData
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{
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Node *var; /* the Var or expression tree */
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RelOptInfo *rel; /* Relation, or NULL if not identifiable */
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HeapTuple statsTuple; /* pg_statistic tuple, or NULL if none */
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/* NB: if statsTuple!=NULL, it must be freed when caller is done */
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void (*freefunc) (HeapTuple tuple); /* how to free statsTuple */
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Oid vartype; /* exposed type of expression */
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Oid atttype; /* actual type (after stripping relabel) */
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int32 atttypmod; /* actual typmod (after stripping relabel) */
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bool isunique; /* matches unique index or DISTINCT clause */
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bool acl_ok; /* result of ACL check on table or column */
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} VariableStatData;
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#define ReleaseVariableStats(vardata) \
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do { \
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if (HeapTupleIsValid((vardata).statsTuple)) \
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(* (vardata).freefunc) ((vardata).statsTuple); \
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} while(0)
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typedef enum
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{
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Pattern_Type_Like, Pattern_Type_Like_IC,
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Pattern_Type_Regex, Pattern_Type_Regex_IC
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} Pattern_Type;
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typedef enum
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{
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Pattern_Prefix_None, Pattern_Prefix_Partial, Pattern_Prefix_Exact
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} Pattern_Prefix_Status;
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/*
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* deconstruct_indexquals is a simple function to examine the indexquals
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* attached to a proposed IndexPath. It returns a list of IndexQualInfo
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* structs, one per qual expression.
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*/
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typedef struct
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{
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RestrictInfo *rinfo; /* the indexqual itself */
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int indexcol; /* zero-based index column number */
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bool varonleft; /* true if index column is on left of qual */
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Oid clause_op; /* qual's operator OID, if relevant */
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Node *other_operand; /* non-index operand of qual's operator */
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} IndexQualInfo;
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/*
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* genericcostestimate is a general-purpose estimator that can be used for
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* most index types. In some cases we use genericcostestimate as the base
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* code and then incorporate additional index-type-specific knowledge in
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* the type-specific calling function. To avoid code duplication, we make
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* genericcostestimate return a number of intermediate values as well as
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* its preliminary estimates of the output cost values. The GenericCosts
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* struct includes all these values.
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*
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* Callers should initialize all fields of GenericCosts to zero. In addition,
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* they can set numIndexTuples to some positive value if they have a better
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* than default way of estimating the number of leaf index tuples visited.
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*/
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typedef struct
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{
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/* These are the values the cost estimator must return to the planner */
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Cost indexStartupCost; /* index-related startup cost */
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Cost indexTotalCost; /* total index-related scan cost */
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Selectivity indexSelectivity; /* selectivity of index */
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double indexCorrelation; /* order correlation of index */
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/* Intermediate values we obtain along the way */
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double numIndexPages; /* number of leaf pages visited */
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double numIndexTuples; /* number of leaf tuples visited */
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double spc_random_page_cost; /* relevant random_page_cost value */
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double num_sa_scans; /* # indexscans from ScalarArrayOps */
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} GenericCosts;
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/* Hooks for plugins to get control when we ask for stats */
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typedef bool (*get_relation_stats_hook_type) (PlannerInfo *root,
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RangeTblEntry *rte,
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AttrNumber attnum,
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VariableStatData *vardata);
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extern PGDLLIMPORT get_relation_stats_hook_type get_relation_stats_hook;
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typedef bool (*get_index_stats_hook_type) (PlannerInfo *root,
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Oid indexOid,
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AttrNumber indexattnum,
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VariableStatData *vardata);
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extern PGDLLIMPORT get_index_stats_hook_type get_index_stats_hook;
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/* Functions in selfuncs.c */
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extern void examine_variable(PlannerInfo *root, Node *node, int varRelid,
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VariableStatData *vardata);
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extern bool statistic_proc_security_check(VariableStatData *vardata, Oid func_oid);
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extern bool get_restriction_variable(PlannerInfo *root, List *args,
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int varRelid,
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VariableStatData *vardata, Node **other,
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bool *varonleft);
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extern void get_join_variables(PlannerInfo *root, List *args,
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SpecialJoinInfo *sjinfo,
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VariableStatData *vardata1,
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VariableStatData *vardata2,
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bool *join_is_reversed);
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extern double get_variable_numdistinct(VariableStatData *vardata,
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bool *isdefault);
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extern double mcv_selectivity(VariableStatData *vardata, FmgrInfo *opproc,
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Datum constval, bool varonleft,
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double *sumcommonp);
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extern double histogram_selectivity(VariableStatData *vardata, FmgrInfo *opproc,
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Datum constval, bool varonleft,
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int min_hist_size, int n_skip,
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int *hist_size);
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extern Pattern_Prefix_Status pattern_fixed_prefix(Const *patt,
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Pattern_Type ptype,
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Oid collation,
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Const **prefix,
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Selectivity *rest_selec);
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extern Const *make_greater_string(const Const *str_const, FmgrInfo *ltproc,
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Oid collation);
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extern Selectivity boolvarsel(PlannerInfo *root, Node *arg, int varRelid);
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extern Selectivity booltestsel(PlannerInfo *root, BoolTestType booltesttype,
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Node *arg, int varRelid,
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JoinType jointype, SpecialJoinInfo *sjinfo);
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extern Selectivity nulltestsel(PlannerInfo *root, NullTestType nulltesttype,
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Node *arg, int varRelid,
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JoinType jointype, SpecialJoinInfo *sjinfo);
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extern Selectivity scalararraysel(PlannerInfo *root,
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ScalarArrayOpExpr *clause,
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bool is_join_clause,
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int varRelid, JoinType jointype, SpecialJoinInfo *sjinfo);
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extern int estimate_array_length(Node *arrayexpr);
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extern Selectivity rowcomparesel(PlannerInfo *root,
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RowCompareExpr *clause,
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int varRelid, JoinType jointype, SpecialJoinInfo *sjinfo);
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extern void mergejoinscansel(PlannerInfo *root, Node *clause,
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Oid opfamily, int strategy, bool nulls_first,
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Selectivity *leftstart, Selectivity *leftend,
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Selectivity *rightstart, Selectivity *rightend);
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extern double estimate_num_groups(PlannerInfo *root, List *groupExprs,
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double input_rows, List **pgset);
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extern Selectivity estimate_hash_bucketsize(PlannerInfo *root, Node *hashkey,
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double nbuckets);
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extern List *deconstruct_indexquals(IndexPath *path);
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extern void genericcostestimate(PlannerInfo *root, IndexPath *path,
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double loop_count,
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List *qinfos,
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GenericCosts *costs);
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/* Functions in array_selfuncs.c */
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extern Selectivity scalararraysel_containment(PlannerInfo *root,
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Node *leftop, Node *rightop,
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Oid elemtype, bool isEquality, bool useOr,
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int varRelid);
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#endif /* SELFUNCS_H */
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