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a4d75c86bf
Allow defining extended statistics on expressions, not just just on
simple column references. With this commit, expressions are supported
by all existing extended statistics kinds, improving the same types of
estimates. A simple example may look like this:
CREATE TABLE t (a int);
CREATE STATISTICS s ON mod(a,10), mod(a,20) FROM t;
ANALYZE t;
The collected statistics are useful e.g. to estimate queries with those
expressions in WHERE or GROUP BY clauses:
SELECT * FROM t WHERE mod(a,10) = 0 AND mod(a,20) = 0;
SELECT 1 FROM t GROUP BY mod(a,10), mod(a,20);
This introduces new internal statistics kind 'e' (expressions) which is
built automatically when the statistics object definition includes any
expressions. This represents single-expression statistics, as if there
was an expression index (but without the index maintenance overhead).
The statistics is stored in pg_statistics_ext_data as an array of
composite types, which is possible thanks to 79f6a942bd.
CREATE STATISTICS allows building statistics on a single expression, in
which case in which case it's not possible to specify statistics kinds.
A new system view pg_stats_ext_exprs can be used to display expression
statistics, similarly to pg_stats and pg_stats_ext views.
ALTER TABLE ... ALTER COLUMN ... TYPE now treats indexes the same way it
treats indexes, i.e. it drops and recreates the statistics. This means
all statistics are reset, and we no longer try to preserve at least the
functional dependencies. This should not be a major issue in practice,
as the functional dependencies actually rely on per-column statistics,
which were always reset anyway.
Author: Tomas Vondra
Reviewed-by: Justin Pryzby, Dean Rasheed, Zhihong Yu
Discussion: https://postgr.es/m/ad7891d2-e90c-b446-9fe2-7419143847d7%40enterprisedb.com
155 lines
6.4 KiB
C
155 lines
6.4 KiB
C
/*-------------------------------------------------------------------------
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*
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* defrem.h
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* POSTGRES define and remove utility definitions.
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*
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*
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* Portions Copyright (c) 1996-2021, 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/commands/defrem.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef DEFREM_H
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#define DEFREM_H
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#include "catalog/objectaddress.h"
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#include "nodes/params.h"
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#include "parser/parse_node.h"
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#include "tcop/dest.h"
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#include "utils/array.h"
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/* commands/dropcmds.c */
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extern void RemoveObjects(DropStmt *stmt);
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/* commands/indexcmds.c */
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extern ObjectAddress DefineIndex(Oid relationId,
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IndexStmt *stmt,
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Oid indexRelationId,
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Oid parentIndexId,
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Oid parentConstraintId,
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bool is_alter_table,
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bool check_rights,
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bool check_not_in_use,
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bool skip_build,
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bool quiet);
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extern void ExecReindex(ParseState *pstate, ReindexStmt *stmt, bool isTopLevel);
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extern char *makeObjectName(const char *name1, const char *name2,
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const char *label);
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extern char *ChooseRelationName(const char *name1, const char *name2,
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const char *label, Oid namespaceid,
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bool isconstraint);
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extern bool CheckIndexCompatible(Oid oldId,
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const char *accessMethodName,
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List *attributeList,
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List *exclusionOpNames);
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extern Oid GetDefaultOpClass(Oid type_id, Oid am_id);
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extern Oid ResolveOpClass(List *opclass, Oid attrType,
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const char *accessMethodName, Oid accessMethodId);
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/* commands/functioncmds.c */
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extern ObjectAddress CreateFunction(ParseState *pstate, CreateFunctionStmt *stmt);
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extern void RemoveFunctionById(Oid funcOid);
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extern ObjectAddress AlterFunction(ParseState *pstate, AlterFunctionStmt *stmt);
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extern ObjectAddress CreateCast(CreateCastStmt *stmt);
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extern ObjectAddress CreateTransform(CreateTransformStmt *stmt);
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extern void IsThereFunctionInNamespace(const char *proname, int pronargs,
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oidvector *proargtypes, Oid nspOid);
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extern void ExecuteDoStmt(DoStmt *stmt, bool atomic);
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extern void ExecuteCallStmt(CallStmt *stmt, ParamListInfo params, bool atomic, DestReceiver *dest);
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extern TupleDesc CallStmtResultDesc(CallStmt *stmt);
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extern Oid get_transform_oid(Oid type_id, Oid lang_id, bool missing_ok);
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extern void interpret_function_parameter_list(ParseState *pstate,
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List *parameters,
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Oid languageOid,
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ObjectType objtype,
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oidvector **parameterTypes,
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ArrayType **allParameterTypes,
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ArrayType **parameterModes,
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ArrayType **parameterNames,
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List **parameterDefaults,
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Oid *variadicArgType,
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Oid *requiredResultType);
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/* commands/operatorcmds.c */
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extern ObjectAddress DefineOperator(List *names, List *parameters);
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extern void RemoveOperatorById(Oid operOid);
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extern ObjectAddress AlterOperator(AlterOperatorStmt *stmt);
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/* commands/statscmds.c */
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extern ObjectAddress CreateStatistics(CreateStatsStmt *stmt);
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extern ObjectAddress AlterStatistics(AlterStatsStmt *stmt);
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extern void RemoveStatisticsById(Oid statsOid);
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extern Oid StatisticsGetRelation(Oid statId, bool missing_ok);
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/* commands/aggregatecmds.c */
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extern ObjectAddress DefineAggregate(ParseState *pstate, List *name, List *args, bool oldstyle,
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List *parameters, bool replace);
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/* commands/opclasscmds.c */
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extern ObjectAddress DefineOpClass(CreateOpClassStmt *stmt);
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extern ObjectAddress DefineOpFamily(CreateOpFamilyStmt *stmt);
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extern Oid AlterOpFamily(AlterOpFamilyStmt *stmt);
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extern void IsThereOpClassInNamespace(const char *opcname, Oid opcmethod,
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Oid opcnamespace);
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extern void IsThereOpFamilyInNamespace(const char *opfname, Oid opfmethod,
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Oid opfnamespace);
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extern Oid get_opclass_oid(Oid amID, List *opclassname, bool missing_ok);
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extern Oid get_opfamily_oid(Oid amID, List *opfamilyname, bool missing_ok);
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/* commands/tsearchcmds.c */
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extern ObjectAddress DefineTSParser(List *names, List *parameters);
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extern ObjectAddress DefineTSDictionary(List *names, List *parameters);
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extern ObjectAddress AlterTSDictionary(AlterTSDictionaryStmt *stmt);
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extern ObjectAddress DefineTSTemplate(List *names, List *parameters);
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extern ObjectAddress DefineTSConfiguration(List *names, List *parameters,
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ObjectAddress *copied);
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extern void RemoveTSConfigurationById(Oid cfgId);
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extern ObjectAddress AlterTSConfiguration(AlterTSConfigurationStmt *stmt);
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extern text *serialize_deflist(List *deflist);
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extern List *deserialize_deflist(Datum txt);
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/* commands/foreigncmds.c */
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extern ObjectAddress AlterForeignServerOwner(const char *name, Oid newOwnerId);
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extern void AlterForeignServerOwner_oid(Oid, Oid newOwnerId);
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extern ObjectAddress AlterForeignDataWrapperOwner(const char *name, Oid newOwnerId);
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extern void AlterForeignDataWrapperOwner_oid(Oid fwdId, Oid newOwnerId);
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extern ObjectAddress CreateForeignDataWrapper(CreateFdwStmt *stmt);
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extern ObjectAddress AlterForeignDataWrapper(AlterFdwStmt *stmt);
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extern ObjectAddress CreateForeignServer(CreateForeignServerStmt *stmt);
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extern ObjectAddress AlterForeignServer(AlterForeignServerStmt *stmt);
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extern ObjectAddress CreateUserMapping(CreateUserMappingStmt *stmt);
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extern ObjectAddress AlterUserMapping(AlterUserMappingStmt *stmt);
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extern Oid RemoveUserMapping(DropUserMappingStmt *stmt);
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extern void CreateForeignTable(CreateForeignTableStmt *stmt, Oid relid);
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extern void ImportForeignSchema(ImportForeignSchemaStmt *stmt);
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extern Datum transformGenericOptions(Oid catalogId,
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Datum oldOptions,
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List *options,
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Oid fdwvalidator);
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/* commands/amcmds.c */
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extern ObjectAddress CreateAccessMethod(CreateAmStmt *stmt);
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extern Oid get_index_am_oid(const char *amname, bool missing_ok);
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extern Oid get_table_am_oid(const char *amname, bool missing_ok);
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extern Oid get_am_oid(const char *amname, bool missing_ok);
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extern char *get_am_name(Oid amOid);
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/* support routines in commands/define.c */
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extern char *defGetString(DefElem *def);
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extern double defGetNumeric(DefElem *def);
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extern bool defGetBoolean(DefElem *def);
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extern int32 defGetInt32(DefElem *def);
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extern int64 defGetInt64(DefElem *def);
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extern List *defGetQualifiedName(DefElem *def);
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extern TypeName *defGetTypeName(DefElem *def);
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extern int defGetTypeLength(DefElem *def);
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extern List *defGetStringList(DefElem *def);
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#endif /* DEFREM_H */
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