849074f9ae
on-the-fly, and thereby avoid blowing out memory when the planner has underestimated the hash table size. Hash join will now obey the work_mem limit with some faithfulness. Per my recent proposal (hash aggregate part isn't done yet though).
132 lines
4.2 KiB
C
132 lines
4.2 KiB
C
/*-------------------------------------------------------------------------
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*
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* selfuncs.h
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* Selectivity functions and index cost estimation functions for
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* standard operators and index access methods.
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*
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*
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* Portions Copyright (c) 1996-2005, 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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* $PostgreSQL: pgsql/src/include/utils/selfuncs.h,v 1.22 2005/03/06 22:15:05 tgl Exp $
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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 "nodes/parsenodes.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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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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/* selfuncs.c */
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extern Pattern_Prefix_Status pattern_fixed_prefix(Const *patt,
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Pattern_Type ptype,
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Const **prefix,
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Const **rest);
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extern Const *make_greater_string(const Const *str_const);
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extern Datum eqsel(PG_FUNCTION_ARGS);
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extern Datum neqsel(PG_FUNCTION_ARGS);
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extern Datum scalarltsel(PG_FUNCTION_ARGS);
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extern Datum scalargtsel(PG_FUNCTION_ARGS);
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extern Datum regexeqsel(PG_FUNCTION_ARGS);
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extern Datum icregexeqsel(PG_FUNCTION_ARGS);
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extern Datum likesel(PG_FUNCTION_ARGS);
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extern Datum iclikesel(PG_FUNCTION_ARGS);
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extern Datum regexnesel(PG_FUNCTION_ARGS);
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extern Datum icregexnesel(PG_FUNCTION_ARGS);
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extern Datum nlikesel(PG_FUNCTION_ARGS);
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extern Datum icnlikesel(PG_FUNCTION_ARGS);
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extern Datum eqjoinsel(PG_FUNCTION_ARGS);
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extern Datum neqjoinsel(PG_FUNCTION_ARGS);
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extern Datum scalarltjoinsel(PG_FUNCTION_ARGS);
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extern Datum scalargtjoinsel(PG_FUNCTION_ARGS);
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extern Datum regexeqjoinsel(PG_FUNCTION_ARGS);
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extern Datum icregexeqjoinsel(PG_FUNCTION_ARGS);
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extern Datum likejoinsel(PG_FUNCTION_ARGS);
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extern Datum iclikejoinsel(PG_FUNCTION_ARGS);
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extern Datum regexnejoinsel(PG_FUNCTION_ARGS);
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extern Datum icregexnejoinsel(PG_FUNCTION_ARGS);
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extern Datum nlikejoinsel(PG_FUNCTION_ARGS);
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extern Datum icnlikejoinsel(PG_FUNCTION_ARGS);
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extern Selectivity booltestsel(Query *root, BoolTestType booltesttype,
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Node *arg, int varRelid, JoinType jointype);
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extern Selectivity nulltestsel(Query *root, NullTestType nulltesttype,
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Node *arg, int varRelid);
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extern void mergejoinscansel(Query *root, Node *clause,
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Selectivity *leftscan,
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Selectivity *rightscan);
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extern double estimate_num_groups(Query *root, List *groupExprs,
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double input_rows);
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extern Selectivity estimate_hash_bucketsize(Query *root, Node *hashkey,
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double nbuckets);
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extern Datum btcostestimate(PG_FUNCTION_ARGS);
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extern Datum rtcostestimate(PG_FUNCTION_ARGS);
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extern Datum hashcostestimate(PG_FUNCTION_ARGS);
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extern Datum gistcostestimate(PG_FUNCTION_ARGS);
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#endif /* SELFUNCS_H */
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