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postgresql/src/include/utils/selfuncs.h

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Optimizer can now estimate selectivity of IS NULL, IS NOT NULL, IS TRUE, etc, with some degree of verisimilitude. Split out selectivity support functions from builtins.h into a new header file selfuncs.h, so as to reduce the number of header files builtins.h must depend on. Fix a few missing inclusions exposed thereby. From Joe Conway, with some kibitzing from Tom Lane.
2001-06-25 23:11:45 +02:00
/*-------------------------------------------------------------------------
*
* selfuncs.h
* Selectivity functions and index cost estimation functions for
* standard operators and index access methods.
*
*
Tag appropriate files for rc3 Also performed an initial run through of upgrading our Copyright date to extend to 2005 ... first run here was very simple ... change everything where: grep 1996-2004 && the word 'Copyright' ... scanned through the generated list with 'less' first, and after, to make sure that I only picked up the right entries ...
2004-12-31 23:04:05 +01:00
* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
Optimizer can now estimate selectivity of IS NULL, IS NOT NULL, IS TRUE, etc, with some degree of verisimilitude. Split out selectivity support functions from builtins.h into a new header file selfuncs.h, so as to reduce the number of header files builtins.h must depend on. Fix a few missing inclusions exposed thereby. From Joe Conway, with some kibitzing from Tom Lane.
2001-06-25 23:11:45 +02:00
* Portions Copyright (c) 1994, Regents of the University of California
*
Teach planner and executor to handle ScalarArrayOpExpr as an indexable qualification when the underlying operator is indexable and useOr is true. That is, indexkey op ANY (ARRAY[...]) is effectively translated into an OR combination of one indexscan for each array element. This only works for bitmap index scans, of course, since regular indexscans no longer support OR'ing of scans. There are still some loose ends to clean up before changing 'x IN (list)' to translate as a ScalarArrayOpExpr; for instance predtest.c ought to be taught about it. But this gets the basic functionality in place.
2005-11-25 20:47:50 +01:00
* $PostgreSQL: pgsql/src/include/utils/selfuncs.h,v 1.26 2005/11/25 19:47:50 tgl Exp $
Optimizer can now estimate selectivity of IS NULL, IS NOT NULL, IS TRUE, etc, with some degree of verisimilitude. Split out selectivity support functions from builtins.h into a new header file selfuncs.h, so as to reduce the number of header files builtins.h must depend on. Fix a few missing inclusions exposed thereby. From Joe Conway, with some kibitzing from Tom Lane.
2001-06-25 23:11:45 +02:00
*
*-------------------------------------------------------------------------
*/
#ifndef SELFUNCS_H
#define SELFUNCS_H
#include "fmgr.h"
Remove planner's private fields from Query struct, and put them into a new PlannerInfo struct, which is passed around instead of the bare Query in all the planning code. This commit is essentially just a code-beautification exercise, but it does open the door to making larger changes to the planner data structures without having to muck with the widely-known Query struct.
2005-06-06 00:32:58 +02:00
#include "nodes/relation.h"
Optimizer can now estimate selectivity of IS NULL, IS NOT NULL, IS TRUE, etc, with some degree of verisimilitude. Split out selectivity support functions from builtins.h into a new header file selfuncs.h, so as to reduce the number of header files builtins.h must depend on. Fix a few missing inclusions exposed thereby. From Joe Conway, with some kibitzing from Tom Lane.
2001-06-25 23:11:45 +02:00
Use a hopefully-more-reliable method of detecting default selectivity estimates when combining the estimates for a range query. As pointed out by Miquel van Smoorenburg, the existing check for an impossible combined result would quite possibly fail to detect one default and one non-default input. It seems better to use the default range query estimate in such cases. To do so, add a check for an estimate of exactly DEFAULT_INEQ_SEL. This is a bit ugly because it introduces additional coupling between clauselist_selectivity and scalarltsel/scalargtsel, but it's not like there wasn't plenty already...
2004-11-09 01:34:46 +01:00
/*
* 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 selectivity estimate for equalities such as "A = b" */
#define DEFAULT_EQ_SEL 0.005
/* 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" */
Standard pgindent run for 8.1.
2005-10-15 04:49:52 +02:00
#define DEFAULT_RANGE_INEQ_SEL 0.005
Use a hopefully-more-reliable method of detecting default selectivity estimates when combining the estimates for a range query. As pointed out by Miquel van Smoorenburg, the existing check for an impossible combined result would quite possibly fail to detect one default and one non-default input. It seems better to use the default range query estimate in such cases. To do so, add a check for an estimate of exactly DEFAULT_INEQ_SEL. This is a bit ugly because it introduces additional coupling between clauselist_selectivity and scalarltsel/scalargtsel, but it's not like there wasn't plenty already...
2004-11-09 01:34:46 +01:00
/* default selectivity estimate for pattern-match operators such as LIKE */
#define DEFAULT_MATCH_SEL 0.005
/* default number of distinct values in a table */
#define DEFAULT_NUM_DISTINCT 200
/* default selectivity estimate for boolean and null test nodes */
#define DEFAULT_UNK_SEL 0.005
#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)
Optimizer can now estimate selectivity of IS NULL, IS NOT NULL, IS TRUE, etc, with some degree of verisimilitude. Split out selectivity support functions from builtins.h into a new header file selfuncs.h, so as to reduce the number of header files builtins.h must depend on. Fix a few missing inclusions exposed thereby. From Joe Conway, with some kibitzing from Tom Lane.
2001-06-25 23:11:45 +02:00
typedef enum
{
Another pgindent run. Fixes enum indenting, and improves #endif spacing. Also adds space for one-line comments.
2001-10-28 07:26:15 +01:00
Pattern_Type_Like, Pattern_Type_Like_IC,
Pattern_Type_Regex, Pattern_Type_Regex_IC
Optimizer can now estimate selectivity of IS NULL, IS NOT NULL, IS TRUE, etc, with some degree of verisimilitude. Split out selectivity support functions from builtins.h into a new header file selfuncs.h, so as to reduce the number of header files builtins.h must depend on. Fix a few missing inclusions exposed thereby. From Joe Conway, with some kibitzing from Tom Lane.
2001-06-25 23:11:45 +02:00
} Pattern_Type;
typedef enum
{
Another pgindent run. Fixes enum indenting, and improves #endif spacing. Also adds space for one-line comments.
2001-10-28 07:26:15 +01:00
Pattern_Prefix_None, Pattern_Prefix_Partial, Pattern_Prefix_Exact
Optimizer can now estimate selectivity of IS NULL, IS NOT NULL, IS TRUE, etc, with some degree of verisimilitude. Split out selectivity support functions from builtins.h into a new header file selfuncs.h, so as to reduce the number of header files builtins.h must depend on. Fix a few missing inclusions exposed thereby. From Joe Conway, with some kibitzing from Tom Lane.
2001-06-25 23:11:45 +02:00
} Pattern_Prefix_Status;
/* selfuncs.c */
> Okay. When you get back to the original issue, the gold is hidden in > src/backend/optimizer/path/indxpath.c; see the "special indexable > operators" stuff near the bottom of that file. (It's a bit of a crock > that this code is hardwired there, and not somehow accessed through a > system catalog, but it's what we've got at the moment.) The attached patch re-enables a bytea right hand argument (as compared to a text right hand argument), and enables index usage, for bytea LIKE Joe Conway
2002-09-02 08:22:20 +02:00
extern Pattern_Prefix_Status pattern_fixed_prefix(Const *patt,
Optimizer can now estimate selectivity of IS NULL, IS NOT NULL, IS TRUE, etc, with some degree of verisimilitude. Split out selectivity support functions from builtins.h into a new header file selfuncs.h, so as to reduce the number of header files builtins.h must depend on. Fix a few missing inclusions exposed thereby. From Joe Conway, with some kibitzing from Tom Lane.
2001-06-25 23:11:45 +02:00
Pattern_Type ptype,
> Okay. When you get back to the original issue, the gold is hidden in > src/backend/optimizer/path/indxpath.c; see the "special indexable > operators" stuff near the bottom of that file. (It's a bit of a crock > that this code is hardwired there, and not somehow accessed through a > system catalog, but it's what we've got at the moment.) The attached patch re-enables a bytea right hand argument (as compared to a text right hand argument), and enables index usage, for bytea LIKE Joe Conway
2002-09-02 08:22:20 +02:00
Const **prefix,
Const **rest);
extern Const *make_greater_string(const Const *str_const);
Optimizer can now estimate selectivity of IS NULL, IS NOT NULL, IS TRUE, etc, with some degree of verisimilitude. Split out selectivity support functions from builtins.h into a new header file selfuncs.h, so as to reduce the number of header files builtins.h must depend on. Fix a few missing inclusions exposed thereby. From Joe Conway, with some kibitzing from Tom Lane.
2001-06-25 23:11:45 +02:00
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);
Remove planner's private fields from Query struct, and put them into a new PlannerInfo struct, which is passed around instead of the bare Query in all the planning code. This commit is essentially just a code-beautification exercise, but it does open the door to making larger changes to the planner data structures without having to muck with the widely-known Query struct.
2005-06-06 00:32:58 +02:00
extern Selectivity booltestsel(PlannerInfo *root, BoolTestType booltesttype,
pgindent run.
2003-08-04 02:43:34 +02:00
Node *arg, int varRelid, JoinType jointype);
Remove planner's private fields from Query struct, and put them into a new PlannerInfo struct, which is passed around instead of the bare Query in all the planning code. This commit is essentially just a code-beautification exercise, but it does open the door to making larger changes to the planner data structures without having to muck with the widely-known Query struct.
2005-06-06 00:32:58 +02:00
extern Selectivity nulltestsel(PlannerInfo *root, NullTestType nulltesttype,
pgindent run.
2003-08-04 02:43:34 +02:00
Node *arg, int varRelid);
Teach planner and executor to handle ScalarArrayOpExpr as an indexable qualification when the underlying operator is indexable and useOr is true. That is, indexkey op ANY (ARRAY[...]) is effectively translated into an OR combination of one indexscan for each array element. This only works for bitmap index scans, of course, since regular indexscans no longer support OR'ing of scans. There are still some loose ends to clean up before changing 'x IN (list)' to translate as a ScalarArrayOpExpr; for instance predtest.c ought to be taught about it. But this gets the basic functionality in place.
2005-11-25 20:47:50 +01:00
extern Selectivity scalararraysel(PlannerInfo *root,
ScalarArrayOpExpr *clause,
bool is_join_clause,
int varRelid, JoinType jointype);
Teach planner about the idea that a mergejoin won't necessarily read both input streams to the end. If one variable's range is much less than the other, an indexscan-based merge can win by not scanning all of the other table. Per example from Reinhard Max.
2002-03-01 05:09:28 +01:00
Remove planner's private fields from Query struct, and put them into a new PlannerInfo struct, which is passed around instead of the bare Query in all the planning code. This commit is essentially just a code-beautification exercise, but it does open the door to making larger changes to the planner data structures without having to muck with the widely-known Query struct.
2005-06-06 00:32:58 +02:00
extern void mergejoinscansel(PlannerInfo *root, Node *clause,
pgindent run.
2002-09-04 22:31:48 +02:00
Selectivity *leftscan,
Selectivity *rightscan);
Optimizer can now estimate selectivity of IS NULL, IS NOT NULL, IS TRUE, etc, with some degree of verisimilitude. Split out selectivity support functions from builtins.h into a new header file selfuncs.h, so as to reduce the number of header files builtins.h must depend on. Fix a few missing inclusions exposed thereby. From Joe Conway, with some kibitzing from Tom Lane.
2001-06-25 23:11:45 +02:00
Remove planner's private fields from Query struct, and put them into a new PlannerInfo struct, which is passed around instead of the bare Query in all the planning code. This commit is essentially just a code-beautification exercise, but it does open the door to making larger changes to the planner data structures without having to muck with the widely-known Query struct.
2005-06-06 00:32:58 +02:00
extern double estimate_num_groups(PlannerInfo *root, List *groupExprs,
pgindent run.
2003-08-04 02:43:34 +02:00
double input_rows);
Add an at-least-marginally-plausible method of estimating the number of groups produced by GROUP BY. This improves the accuracy of planning estimates for grouped subselects, and is needed to check whether a hashed aggregation plan risks memory overflow.
2002-11-20 00:22:00 +01:00
Remove planner's private fields from Query struct, and put them into a new PlannerInfo struct, which is passed around instead of the bare Query in all the planning code. This commit is essentially just a code-beautification exercise, but it does open the door to making larger changes to the planner data structures without having to muck with the widely-known Query struct.
2005-06-06 00:32:58 +02:00
extern Selectivity estimate_hash_bucketsize(PlannerInfo *root, Node *hashkey,
Revise hash join code so that we can increase the number of batches 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).
2005-03-06 23:15:05 +01:00
double nbuckets);
Make use of statistics on index expressions. There are still some corner cases that could stand improvement, but it does all the basic stuff. A byproduct is that the selectivity routines are no longer constrained to working on simple Vars; we might in future be able to improve the behavior for subexpressions that don't match indexes.
2004-02-17 01:52:53 +01:00
Optimizer can now estimate selectivity of IS NULL, IS NOT NULL, IS TRUE, etc, with some degree of verisimilitude. Split out selectivity support functions from builtins.h into a new header file selfuncs.h, so as to reduce the number of header files builtins.h must depend on. Fix a few missing inclusions exposed thereby. From Joe Conway, with some kibitzing from Tom Lane.
2001-06-25 23:11:45 +02:00
extern Datum btcostestimate(PG_FUNCTION_ARGS);
extern Datum hashcostestimate(PG_FUNCTION_ARGS);
extern Datum gistcostestimate(PG_FUNCTION_ARGS);
Another pgindent run. Fixes enum indenting, and improves #endif spacing. Also adds space for one-line comments.
2001-10-28 07:26:15 +01:00
New pgindent run with fixes suggested by Tom. Patch manually reviewed, initdb/regression tests pass.
2001-11-05 18:46:40 +01:00
#endif /* SELFUNCS_H */