postgresql/src/include/optimizer/optimizer.h
Tom Lane 5c11104c7d Ensure we preprocess expressions before checking their volatility.
contain_mutable_functions and contain_volatile_functions give
reliable answers only after expression preprocessing (specifically
eval_const_expressions).  Some places understand this, but some did
not get the memo --- which is not entirely their fault, because the
problem is documented only in places far away from those functions.
Introduce wrapper functions that allow doing the right thing easily,
and add commentary in hopes of preventing future mistakes from
copy-and-paste of code that's only conditionally safe.

Two actual bugs of this ilk are fixed here.  We failed to preprocess
column GENERATED expressions before checking mutability, so that the
code could fail to detect the use of a volatile function
default-argument expression, or it could reject a polymorphic function
that is actually immutable on the datatype of interest.  Likewise,
column DEFAULT expressions weren't preprocessed before determining if
it's safe to apply the attmissingval mechanism.  A false negative
would just result in an unnecessary table rewrite, but a false
positive could allow the attmissingval mechanism to be used in a case
where it should not be, resulting in unexpected initial values in a
new column.

In passing, re-order the steps in ComputePartitionAttrs so that its
checks for invalid column references are done before applying
expression_planner, rather than after.  The previous coding would
not complain if a partition expression contains a disallowed column
reference that gets optimized away by constant folding, which seems
to me to be a behavior we do not want.

Per bug #18097 from Jim Keener.  Back-patch to all supported versions.

Discussion: https://postgr.es/m/18097-ebb179674f22932f@postgresql.org
2023-11-16 10:05:14 -05:00

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C

/*-------------------------------------------------------------------------
*
* optimizer.h
* External API for the Postgres planner.
*
* This header is meant to define everything that the core planner
* exposes for use by non-planner modules.
*
* Note that there are files outside src/backend/optimizer/ that are
* considered planner modules, because they're too much in bed with
* planner operations to be treated otherwise. FDW planning code is an
* example. For the most part, however, code outside the core planner
* should not need to include any optimizer/ header except this one.
*
* Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/optimizer/optimizer.h
*
*-------------------------------------------------------------------------
*/
#ifndef OPTIMIZER_H
#define OPTIMIZER_H
#include "nodes/parsenodes.h"
/*
* We don't want to include nodes/pathnodes.h here, because non-planner
* code should generally treat PlannerInfo as an opaque typedef.
* But we'd like such code to use that typedef name, so define the
* typedef either here or in pathnodes.h, whichever is read first.
*/
#ifndef HAVE_PLANNERINFO_TYPEDEF
typedef struct PlannerInfo PlannerInfo;
#define HAVE_PLANNERINFO_TYPEDEF 1
#endif
/* Likewise for IndexOptInfo and SpecialJoinInfo. */
#ifndef HAVE_INDEXOPTINFO_TYPEDEF
typedef struct IndexOptInfo IndexOptInfo;
#define HAVE_INDEXOPTINFO_TYPEDEF 1
#endif
#ifndef HAVE_SPECIALJOININFO_TYPEDEF
typedef struct SpecialJoinInfo SpecialJoinInfo;
#define HAVE_SPECIALJOININFO_TYPEDEF 1
#endif
/* It also seems best not to include plannodes.h, params.h, or htup.h here */
struct PlannedStmt;
struct ParamListInfoData;
struct HeapTupleData;
/* in path/clausesel.c: */
extern Selectivity clause_selectivity(PlannerInfo *root,
Node *clause,
int varRelid,
JoinType jointype,
SpecialJoinInfo *sjinfo);
extern Selectivity clauselist_selectivity_simple(PlannerInfo *root,
List *clauses,
int varRelid,
JoinType jointype,
SpecialJoinInfo *sjinfo,
Bitmapset *estimatedclauses);
extern Selectivity clauselist_selectivity(PlannerInfo *root,
List *clauses,
int varRelid,
JoinType jointype,
SpecialJoinInfo *sjinfo);
/* in path/costsize.c: */
/* widely used cost parameters */
extern PGDLLIMPORT double seq_page_cost;
extern PGDLLIMPORT double random_page_cost;
extern PGDLLIMPORT double cpu_tuple_cost;
extern PGDLLIMPORT double cpu_index_tuple_cost;
extern PGDLLIMPORT double cpu_operator_cost;
extern PGDLLIMPORT double parallel_tuple_cost;
extern PGDLLIMPORT double parallel_setup_cost;
extern PGDLLIMPORT int effective_cache_size;
extern double clamp_row_est(double nrows);
/* in path/indxpath.c: */
extern bool is_pseudo_constant_for_index(Node *expr, IndexOptInfo *index);
extern bool is_pseudo_constant_for_index_new(PlannerInfo *root, Node *expr,
IndexOptInfo *index);
/* in plan/planner.c: */
/* possible values for force_parallel_mode */
typedef enum
{
FORCE_PARALLEL_OFF,
FORCE_PARALLEL_ON,
FORCE_PARALLEL_REGRESS
} ForceParallelMode;
/* GUC parameters */
extern int force_parallel_mode;
extern bool parallel_leader_participation;
extern struct PlannedStmt *planner(Query *parse, const char *query_string,
int cursorOptions,
struct ParamListInfoData *boundParams);
extern Expr *expression_planner(Expr *expr);
extern Expr *expression_planner_with_deps(Expr *expr,
List **relationOids,
List **invalItems);
extern bool plan_cluster_use_sort(Oid tableOid, Oid indexOid);
extern int plan_create_index_workers(Oid tableOid, Oid indexOid);
/* in plan/setrefs.c: */
extern void extract_query_dependencies(Node *query,
List **relationOids,
List **invalItems,
bool *hasRowSecurity);
/* in prep/prepqual.c: */
extern Node *negate_clause(Node *node);
extern Expr *canonicalize_qual(Expr *qual, bool is_check);
/* in util/clauses.c: */
extern bool contain_mutable_functions(Node *clause);
extern bool contain_mutable_functions_after_planning(Expr *expr);
extern bool contain_volatile_functions(Node *clause);
extern bool contain_volatile_functions_after_planning(Expr *expr);
extern bool contain_volatile_functions_not_nextval(Node *clause);
extern Node *eval_const_expressions(PlannerInfo *root, Node *node);
extern Node *estimate_expression_value(PlannerInfo *root, Node *node);
extern Expr *evaluate_expr(Expr *expr, Oid result_type, int32 result_typmod,
Oid result_collation);
extern List *expand_function_arguments(List *args, Oid result_type,
struct HeapTupleData *func_tuple);
/* in util/predtest.c: */
extern bool predicate_implied_by(List *predicate_list, List *clause_list,
bool weak);
extern bool predicate_refuted_by(List *predicate_list, List *clause_list,
bool weak);
/* in util/tlist.c: */
extern int count_nonjunk_tlist_entries(List *tlist);
extern TargetEntry *get_sortgroupref_tle(Index sortref,
List *targetList);
extern TargetEntry *get_sortgroupclause_tle(SortGroupClause *sgClause,
List *targetList);
extern Node *get_sortgroupclause_expr(SortGroupClause *sgClause,
List *targetList);
extern List *get_sortgrouplist_exprs(List *sgClauses,
List *targetList);
extern SortGroupClause *get_sortgroupref_clause(Index sortref,
List *clauses);
extern SortGroupClause *get_sortgroupref_clause_noerr(Index sortref,
List *clauses);
/* in util/var.c: */
/* Bits that can be OR'd into the flags argument of pull_var_clause() */
#define PVC_INCLUDE_AGGREGATES 0x0001 /* include Aggrefs in output list */
#define PVC_RECURSE_AGGREGATES 0x0002 /* recurse into Aggref arguments */
#define PVC_INCLUDE_WINDOWFUNCS 0x0004 /* include WindowFuncs in output list */
#define PVC_RECURSE_WINDOWFUNCS 0x0008 /* recurse into WindowFunc arguments */
#define PVC_INCLUDE_PLACEHOLDERS 0x0010 /* include PlaceHolderVars in
* output list */
#define PVC_RECURSE_PLACEHOLDERS 0x0020 /* recurse into PlaceHolderVar
* arguments */
extern Bitmapset *pull_varnos(Node *node);
extern Bitmapset *pull_varnos_of_level(Node *node, int levelsup);
extern Bitmapset *pull_varnos_new(PlannerInfo *root, Node *node);
extern Bitmapset *pull_varnos_of_level_new(PlannerInfo *root, Node *node, int levelsup);
extern void pull_varattnos(Node *node, Index varno, Bitmapset **varattnos);
extern List *pull_vars_of_level(Node *node, int levelsup);
extern bool contain_var_clause(Node *node);
extern bool contain_vars_of_level(Node *node, int levelsup);
extern int locate_var_of_level(Node *node, int levelsup);
extern List *pull_var_clause(Node *node, int flags);
extern Node *flatten_join_alias_vars(Query *query, Node *node);
#endif /* OPTIMIZER_H */