5212 lines
159 KiB
C
5212 lines
159 KiB
C
/*-------------------------------------------------------------------------
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*
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* clauses.c
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* routines to manipulate qualification clauses
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*
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* Portions Copyright (c) 1996-2020, 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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*
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* IDENTIFICATION
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* src/backend/optimizer/util/clauses.c
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*
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* HISTORY
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* AUTHOR DATE MAJOR EVENT
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* Andrew Yu Nov 3, 1994 clause.c and clauses.c combined
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "access/htup_details.h"
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#include "catalog/pg_aggregate.h"
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#include "catalog/pg_class.h"
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#include "catalog/pg_language.h"
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#include "catalog/pg_operator.h"
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#include "catalog/pg_proc.h"
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#include "catalog/pg_type.h"
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#include "executor/executor.h"
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#include "executor/functions.h"
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#include "funcapi.h"
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#include "miscadmin.h"
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#include "nodes/makefuncs.h"
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#include "nodes/nodeFuncs.h"
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#include "nodes/supportnodes.h"
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#include "optimizer/clauses.h"
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#include "optimizer/cost.h"
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#include "optimizer/optimizer.h"
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#include "optimizer/plancat.h"
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#include "optimizer/planmain.h"
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#include "parser/analyze.h"
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#include "parser/parse_agg.h"
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#include "parser/parse_coerce.h"
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#include "parser/parse_func.h"
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#include "rewrite/rewriteManip.h"
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#include "tcop/tcopprot.h"
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#include "utils/acl.h"
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#include "utils/builtins.h"
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#include "utils/datum.h"
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#include "utils/fmgroids.h"
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#include "utils/lsyscache.h"
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#include "utils/memutils.h"
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#include "utils/syscache.h"
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#include "utils/typcache.h"
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typedef struct
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{
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PlannerInfo *root;
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AggSplit aggsplit;
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AggClauseCosts *costs;
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} get_agg_clause_costs_context;
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typedef struct
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{
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ParamListInfo boundParams;
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PlannerInfo *root;
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List *active_fns;
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Node *case_val;
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bool estimate;
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} eval_const_expressions_context;
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typedef struct
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{
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int nargs;
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List *args;
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int *usecounts;
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} substitute_actual_parameters_context;
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typedef struct
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{
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int nargs;
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List *args;
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int sublevels_up;
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} substitute_actual_srf_parameters_context;
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typedef struct
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{
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char *proname;
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char *prosrc;
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} inline_error_callback_arg;
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typedef struct
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{
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char max_hazard; /* worst proparallel hazard found so far */
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char max_interesting; /* worst proparallel hazard of interest */
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List *safe_param_ids; /* PARAM_EXEC Param IDs to treat as safe */
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} max_parallel_hazard_context;
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static bool contain_agg_clause_walker(Node *node, void *context);
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static bool get_agg_clause_costs_walker(Node *node,
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get_agg_clause_costs_context *context);
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static bool find_window_functions_walker(Node *node, WindowFuncLists *lists);
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static bool contain_subplans_walker(Node *node, void *context);
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static bool contain_mutable_functions_walker(Node *node, void *context);
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static bool contain_volatile_functions_walker(Node *node, void *context);
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static bool contain_volatile_functions_not_nextval_walker(Node *node, void *context);
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static bool max_parallel_hazard_walker(Node *node,
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max_parallel_hazard_context *context);
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static bool contain_nonstrict_functions_walker(Node *node, void *context);
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static bool contain_exec_param_walker(Node *node, List *param_ids);
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static bool contain_context_dependent_node(Node *clause);
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static bool contain_context_dependent_node_walker(Node *node, int *flags);
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static bool contain_leaked_vars_walker(Node *node, void *context);
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static Relids find_nonnullable_rels_walker(Node *node, bool top_level);
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static List *find_nonnullable_vars_walker(Node *node, bool top_level);
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static bool is_strict_saop(ScalarArrayOpExpr *expr, bool falseOK);
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static Node *eval_const_expressions_mutator(Node *node,
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eval_const_expressions_context *context);
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static bool contain_non_const_walker(Node *node, void *context);
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static bool ece_function_is_safe(Oid funcid,
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eval_const_expressions_context *context);
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static Node *apply_const_relabel(Node *arg, Oid rtype,
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int32 rtypmod, Oid rcollid,
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CoercionForm rformat, int rlocation);
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static List *simplify_or_arguments(List *args,
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eval_const_expressions_context *context,
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bool *haveNull, bool *forceTrue);
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static List *simplify_and_arguments(List *args,
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eval_const_expressions_context *context,
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bool *haveNull, bool *forceFalse);
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static Node *simplify_boolean_equality(Oid opno, List *args);
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static Expr *simplify_function(Oid funcid,
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Oid result_type, int32 result_typmod,
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Oid result_collid, Oid input_collid, List **args_p,
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bool funcvariadic, bool process_args, bool allow_non_const,
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eval_const_expressions_context *context);
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static List *reorder_function_arguments(List *args, HeapTuple func_tuple);
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static List *add_function_defaults(List *args, HeapTuple func_tuple);
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static List *fetch_function_defaults(HeapTuple func_tuple);
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static void recheck_cast_function_args(List *args, Oid result_type,
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HeapTuple func_tuple);
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static Expr *evaluate_function(Oid funcid, Oid result_type, int32 result_typmod,
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Oid result_collid, Oid input_collid, List *args,
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bool funcvariadic,
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HeapTuple func_tuple,
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eval_const_expressions_context *context);
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static Expr *inline_function(Oid funcid, Oid result_type, Oid result_collid,
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Oid input_collid, List *args,
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bool funcvariadic,
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HeapTuple func_tuple,
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eval_const_expressions_context *context);
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static Node *substitute_actual_parameters(Node *expr, int nargs, List *args,
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int *usecounts);
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static Node *substitute_actual_parameters_mutator(Node *node,
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substitute_actual_parameters_context *context);
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static void sql_inline_error_callback(void *arg);
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static Query *substitute_actual_srf_parameters(Query *expr,
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int nargs, List *args);
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static Node *substitute_actual_srf_parameters_mutator(Node *node,
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substitute_actual_srf_parameters_context *context);
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/*****************************************************************************
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* Aggregate-function clause manipulation
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*****************************************************************************/
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/*
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* contain_agg_clause
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* Recursively search for Aggref/GroupingFunc nodes within a clause.
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*
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* Returns true if any aggregate found.
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*
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* This does not descend into subqueries, and so should be used only after
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* reduction of sublinks to subplans, or in contexts where it's known there
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* are no subqueries. There mustn't be outer-aggregate references either.
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*
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* (If you want something like this but able to deal with subqueries,
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* see rewriteManip.c's contain_aggs_of_level().)
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*/
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bool
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contain_agg_clause(Node *clause)
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{
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return contain_agg_clause_walker(clause, NULL);
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}
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static bool
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contain_agg_clause_walker(Node *node, void *context)
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{
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if (node == NULL)
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return false;
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if (IsA(node, Aggref))
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{
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Assert(((Aggref *) node)->agglevelsup == 0);
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return true; /* abort the tree traversal and return true */
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}
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if (IsA(node, GroupingFunc))
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{
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Assert(((GroupingFunc *) node)->agglevelsup == 0);
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return true; /* abort the tree traversal and return true */
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}
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Assert(!IsA(node, SubLink));
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return expression_tree_walker(node, contain_agg_clause_walker, context);
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}
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/*
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* get_agg_clause_costs
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* Recursively find the Aggref nodes in an expression tree, and
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* accumulate cost information about them.
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*
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* 'aggsplit' tells us the expected partial-aggregation mode, which affects
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* the cost estimates.
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*
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* NOTE that the counts/costs are ADDED to those already in *costs ... so
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* the caller is responsible for zeroing the struct initially.
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*
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* We count the nodes, estimate their execution costs, and estimate the total
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* space needed for their transition state values if all are evaluated in
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* parallel (as would be done in a HashAgg plan). Also, we check whether
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* partial aggregation is feasible. See AggClauseCosts for the exact set
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* of statistics collected.
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*
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* In addition, we mark Aggref nodes with the correct aggtranstype, so
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* that that doesn't need to be done repeatedly. (That makes this function's
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* name a bit of a misnomer.)
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*
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* This does not descend into subqueries, and so should be used only after
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* reduction of sublinks to subplans, or in contexts where it's known there
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* are no subqueries. There mustn't be outer-aggregate references either.
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*/
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void
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get_agg_clause_costs(PlannerInfo *root, Node *clause, AggSplit aggsplit,
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AggClauseCosts *costs)
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{
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get_agg_clause_costs_context context;
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context.root = root;
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context.aggsplit = aggsplit;
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context.costs = costs;
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(void) get_agg_clause_costs_walker(clause, &context);
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}
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static bool
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get_agg_clause_costs_walker(Node *node, get_agg_clause_costs_context *context)
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{
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if (node == NULL)
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return false;
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if (IsA(node, Aggref))
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{
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Aggref *aggref = (Aggref *) node;
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AggClauseCosts *costs = context->costs;
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HeapTuple aggTuple;
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Form_pg_aggregate aggform;
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Oid aggtransfn;
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Oid aggfinalfn;
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Oid aggcombinefn;
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Oid aggserialfn;
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Oid aggdeserialfn;
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Oid aggtranstype;
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int32 aggtransspace;
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QualCost argcosts;
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Assert(aggref->agglevelsup == 0);
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/*
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* Fetch info about aggregate from pg_aggregate. Note it's correct to
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* ignore the moving-aggregate variant, since what we're concerned
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* with here is aggregates not window functions.
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*/
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aggTuple = SearchSysCache1(AGGFNOID,
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ObjectIdGetDatum(aggref->aggfnoid));
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if (!HeapTupleIsValid(aggTuple))
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elog(ERROR, "cache lookup failed for aggregate %u",
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aggref->aggfnoid);
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aggform = (Form_pg_aggregate) GETSTRUCT(aggTuple);
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aggtransfn = aggform->aggtransfn;
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aggfinalfn = aggform->aggfinalfn;
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aggcombinefn = aggform->aggcombinefn;
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aggserialfn = aggform->aggserialfn;
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aggdeserialfn = aggform->aggdeserialfn;
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aggtranstype = aggform->aggtranstype;
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aggtransspace = aggform->aggtransspace;
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ReleaseSysCache(aggTuple);
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/*
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* Resolve the possibly-polymorphic aggregate transition type, unless
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* already done in a previous pass over the expression.
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*/
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if (OidIsValid(aggref->aggtranstype))
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aggtranstype = aggref->aggtranstype;
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else
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{
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Oid inputTypes[FUNC_MAX_ARGS];
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int numArguments;
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/* extract argument types (ignoring any ORDER BY expressions) */
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numArguments = get_aggregate_argtypes(aggref, inputTypes);
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/* resolve actual type of transition state, if polymorphic */
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aggtranstype = resolve_aggregate_transtype(aggref->aggfnoid,
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aggtranstype,
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inputTypes,
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numArguments);
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aggref->aggtranstype = aggtranstype;
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}
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/*
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* Count it, and check for cases requiring ordered input. Note that
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* ordered-set aggs always have nonempty aggorder. Any ordered-input
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* case also defeats partial aggregation.
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*/
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costs->numAggs++;
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if (aggref->aggorder != NIL || aggref->aggdistinct != NIL)
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{
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costs->numOrderedAggs++;
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costs->hasNonPartial = true;
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}
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/*
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* Check whether partial aggregation is feasible, unless we already
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* found out that we can't do it.
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*/
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if (!costs->hasNonPartial)
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{
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/*
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* If there is no combine function, then partial aggregation is
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* not possible.
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*/
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if (!OidIsValid(aggcombinefn))
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costs->hasNonPartial = true;
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/*
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* If we have any aggs with transtype INTERNAL then we must check
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* whether they have serialization/deserialization functions; if
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* not, we can't serialize partial-aggregation results.
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*/
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else if (aggtranstype == INTERNALOID &&
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(!OidIsValid(aggserialfn) || !OidIsValid(aggdeserialfn)))
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costs->hasNonSerial = true;
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}
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/*
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* Add the appropriate component function execution costs to
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* appropriate totals.
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*/
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if (DO_AGGSPLIT_COMBINE(context->aggsplit))
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{
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/* charge for combining previously aggregated states */
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add_function_cost(context->root, aggcombinefn, NULL,
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&costs->transCost);
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}
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else
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add_function_cost(context->root, aggtransfn, NULL,
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&costs->transCost);
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if (DO_AGGSPLIT_DESERIALIZE(context->aggsplit) &&
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OidIsValid(aggdeserialfn))
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add_function_cost(context->root, aggdeserialfn, NULL,
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&costs->transCost);
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if (DO_AGGSPLIT_SERIALIZE(context->aggsplit) &&
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OidIsValid(aggserialfn))
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add_function_cost(context->root, aggserialfn, NULL,
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&costs->finalCost);
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if (!DO_AGGSPLIT_SKIPFINAL(context->aggsplit) &&
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OidIsValid(aggfinalfn))
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add_function_cost(context->root, aggfinalfn, NULL,
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&costs->finalCost);
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/*
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* These costs are incurred only by the initial aggregate node, so we
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* mustn't include them again at upper levels.
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*/
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if (!DO_AGGSPLIT_COMBINE(context->aggsplit))
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{
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/* add the input expressions' cost to per-input-row costs */
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cost_qual_eval_node(&argcosts, (Node *) aggref->args, context->root);
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costs->transCost.startup += argcosts.startup;
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costs->transCost.per_tuple += argcosts.per_tuple;
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/*
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* Add any filter's cost to per-input-row costs.
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*
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* XXX Ideally we should reduce input expression costs according
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* to filter selectivity, but it's not clear it's worth the
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* trouble.
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*/
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if (aggref->aggfilter)
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{
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cost_qual_eval_node(&argcosts, (Node *) aggref->aggfilter,
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context->root);
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costs->transCost.startup += argcosts.startup;
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costs->transCost.per_tuple += argcosts.per_tuple;
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}
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}
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/*
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* If there are direct arguments, treat their evaluation cost like the
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* cost of the finalfn.
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*/
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if (aggref->aggdirectargs)
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{
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cost_qual_eval_node(&argcosts, (Node *) aggref->aggdirectargs,
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context->root);
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costs->finalCost.startup += argcosts.startup;
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costs->finalCost.per_tuple += argcosts.per_tuple;
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}
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/*
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* If the transition type is pass-by-value then it doesn't add
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* anything to the required size of the hashtable. If it is
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* pass-by-reference then we have to add the estimated size of the
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* value itself, plus palloc overhead.
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*/
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if (!get_typbyval(aggtranstype))
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{
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int32 avgwidth;
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/* Use average width if aggregate definition gave one */
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if (aggtransspace > 0)
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avgwidth = aggtransspace;
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else if (aggtransfn == F_ARRAY_APPEND)
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{
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/*
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* If the transition function is array_append(), it'll use an
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* expanded array as transvalue, which will occupy at least
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* ALLOCSET_SMALL_INITSIZE and possibly more. Use that as the
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* estimate for lack of a better idea.
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*/
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avgwidth = ALLOCSET_SMALL_INITSIZE;
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}
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else
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{
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/*
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* If transition state is of same type as first aggregated
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* input, assume it's the same typmod (same width) as well.
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* This works for cases like MAX/MIN and is probably somewhat
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* reasonable otherwise.
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*/
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int32 aggtranstypmod = -1;
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if (aggref->args)
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{
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TargetEntry *tle = (TargetEntry *) linitial(aggref->args);
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if (aggtranstype == exprType((Node *) tle->expr))
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aggtranstypmod = exprTypmod((Node *) tle->expr);
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}
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avgwidth = get_typavgwidth(aggtranstype, aggtranstypmod);
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}
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avgwidth = MAXALIGN(avgwidth);
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costs->transitionSpace += avgwidth + 2 * sizeof(void *);
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}
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else if (aggtranstype == INTERNALOID)
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{
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/*
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* INTERNAL transition type is a special case: although INTERNAL
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* is pass-by-value, it's almost certainly being used as a pointer
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* to some large data structure. The aggregate definition can
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* provide an estimate of the size. If it doesn't, then we assume
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* ALLOCSET_DEFAULT_INITSIZE, which is a good guess if the data is
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* being kept in a private memory context, as is done by
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* array_agg() for instance.
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*/
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if (aggtransspace > 0)
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costs->transitionSpace += aggtransspace;
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else
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costs->transitionSpace += ALLOCSET_DEFAULT_INITSIZE;
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}
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/*
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* We assume that the parser checked that there are no aggregates (of
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* this level anyway) in the aggregated arguments, direct arguments,
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* or filter clause. Hence, we need not recurse into any of them.
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*/
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return false;
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}
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Assert(!IsA(node, SubLink));
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return expression_tree_walker(node, get_agg_clause_costs_walker,
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(void *) context);
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}
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|
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/*****************************************************************************
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* Window-function clause manipulation
|
|
*****************************************************************************/
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|
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/*
|
|
* contain_window_function
|
|
* Recursively search for WindowFunc nodes within a clause.
|
|
*
|
|
* Since window functions don't have level fields, but are hard-wired to
|
|
* be associated with the current query level, this is just the same as
|
|
* rewriteManip.c's function.
|
|
*/
|
|
bool
|
|
contain_window_function(Node *clause)
|
|
{
|
|
return contain_windowfuncs(clause);
|
|
}
|
|
|
|
/*
|
|
* find_window_functions
|
|
* Locate all the WindowFunc nodes in an expression tree, and organize
|
|
* them by winref ID number.
|
|
*
|
|
* Caller must provide an upper bound on the winref IDs expected in the tree.
|
|
*/
|
|
WindowFuncLists *
|
|
find_window_functions(Node *clause, Index maxWinRef)
|
|
{
|
|
WindowFuncLists *lists = palloc(sizeof(WindowFuncLists));
|
|
|
|
lists->numWindowFuncs = 0;
|
|
lists->maxWinRef = maxWinRef;
|
|
lists->windowFuncs = (List **) palloc0((maxWinRef + 1) * sizeof(List *));
|
|
(void) find_window_functions_walker(clause, lists);
|
|
return lists;
|
|
}
|
|
|
|
static bool
|
|
find_window_functions_walker(Node *node, WindowFuncLists *lists)
|
|
{
|
|
if (node == NULL)
|
|
return false;
|
|
if (IsA(node, WindowFunc))
|
|
{
|
|
WindowFunc *wfunc = (WindowFunc *) node;
|
|
|
|
/* winref is unsigned, so one-sided test is OK */
|
|
if (wfunc->winref > lists->maxWinRef)
|
|
elog(ERROR, "WindowFunc contains out-of-range winref %u",
|
|
wfunc->winref);
|
|
/* eliminate duplicates, so that we avoid repeated computation */
|
|
if (!list_member(lists->windowFuncs[wfunc->winref], wfunc))
|
|
{
|
|
lists->windowFuncs[wfunc->winref] =
|
|
lappend(lists->windowFuncs[wfunc->winref], wfunc);
|
|
lists->numWindowFuncs++;
|
|
}
|
|
|
|
/*
|
|
* We assume that the parser checked that there are no window
|
|
* functions in the arguments or filter clause. Hence, we need not
|
|
* recurse into them. (If either the parser or the planner screws up
|
|
* on this point, the executor will still catch it; see ExecInitExpr.)
|
|
*/
|
|
return false;
|
|
}
|
|
Assert(!IsA(node, SubLink));
|
|
return expression_tree_walker(node, find_window_functions_walker,
|
|
(void *) lists);
|
|
}
|
|
|
|
|
|
/*****************************************************************************
|
|
* Support for expressions returning sets
|
|
*****************************************************************************/
|
|
|
|
/*
|
|
* expression_returns_set_rows
|
|
* Estimate the number of rows returned by a set-returning expression.
|
|
* The result is 1 if it's not a set-returning expression.
|
|
*
|
|
* We should only examine the top-level function or operator; it used to be
|
|
* appropriate to recurse, but not anymore. (Even if there are more SRFs in
|
|
* the function's inputs, their multipliers are accounted for separately.)
|
|
*
|
|
* Note: keep this in sync with expression_returns_set() in nodes/nodeFuncs.c.
|
|
*/
|
|
double
|
|
expression_returns_set_rows(PlannerInfo *root, Node *clause)
|
|
{
|
|
if (clause == NULL)
|
|
return 1.0;
|
|
if (IsA(clause, FuncExpr))
|
|
{
|
|
FuncExpr *expr = (FuncExpr *) clause;
|
|
|
|
if (expr->funcretset)
|
|
return clamp_row_est(get_function_rows(root, expr->funcid, clause));
|
|
}
|
|
if (IsA(clause, OpExpr))
|
|
{
|
|
OpExpr *expr = (OpExpr *) clause;
|
|
|
|
if (expr->opretset)
|
|
{
|
|
set_opfuncid(expr);
|
|
return clamp_row_est(get_function_rows(root, expr->opfuncid, clause));
|
|
}
|
|
}
|
|
return 1.0;
|
|
}
|
|
|
|
|
|
/*****************************************************************************
|
|
* Subplan clause manipulation
|
|
*****************************************************************************/
|
|
|
|
/*
|
|
* contain_subplans
|
|
* Recursively search for subplan nodes within a clause.
|
|
*
|
|
* If we see a SubLink node, we will return true. This is only possible if
|
|
* the expression tree hasn't yet been transformed by subselect.c. We do not
|
|
* know whether the node will produce a true subplan or just an initplan,
|
|
* but we make the conservative assumption that it will be a subplan.
|
|
*
|
|
* Returns true if any subplan found.
|
|
*/
|
|
bool
|
|
contain_subplans(Node *clause)
|
|
{
|
|
return contain_subplans_walker(clause, NULL);
|
|
}
|
|
|
|
static bool
|
|
contain_subplans_walker(Node *node, void *context)
|
|
{
|
|
if (node == NULL)
|
|
return false;
|
|
if (IsA(node, SubPlan) ||
|
|
IsA(node, AlternativeSubPlan) ||
|
|
IsA(node, SubLink))
|
|
return true; /* abort the tree traversal and return true */
|
|
return expression_tree_walker(node, contain_subplans_walker, context);
|
|
}
|
|
|
|
|
|
/*****************************************************************************
|
|
* Check clauses for mutable functions
|
|
*****************************************************************************/
|
|
|
|
/*
|
|
* contain_mutable_functions
|
|
* Recursively search for mutable functions within a clause.
|
|
*
|
|
* Returns true if any mutable function (or operator implemented by a
|
|
* mutable function) is found. This test is needed so that we don't
|
|
* mistakenly think that something like "WHERE random() < 0.5" can be treated
|
|
* as a constant qualification.
|
|
*
|
|
* We will recursively look into Query nodes (i.e., SubLink sub-selects)
|
|
* but not into SubPlans. See comments for contain_volatile_functions().
|
|
*/
|
|
bool
|
|
contain_mutable_functions(Node *clause)
|
|
{
|
|
return contain_mutable_functions_walker(clause, NULL);
|
|
}
|
|
|
|
static bool
|
|
contain_mutable_functions_checker(Oid func_id, void *context)
|
|
{
|
|
return (func_volatile(func_id) != PROVOLATILE_IMMUTABLE);
|
|
}
|
|
|
|
static bool
|
|
contain_mutable_functions_walker(Node *node, void *context)
|
|
{
|
|
if (node == NULL)
|
|
return false;
|
|
/* Check for mutable functions in node itself */
|
|
if (check_functions_in_node(node, contain_mutable_functions_checker,
|
|
context))
|
|
return true;
|
|
|
|
if (IsA(node, SQLValueFunction))
|
|
{
|
|
/* all variants of SQLValueFunction are stable */
|
|
return true;
|
|
}
|
|
|
|
if (IsA(node, NextValueExpr))
|
|
{
|
|
/* NextValueExpr is volatile */
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* It should be safe to treat MinMaxExpr as immutable, because it will
|
|
* depend on a non-cross-type btree comparison function, and those should
|
|
* always be immutable. Treating XmlExpr as immutable is more dubious,
|
|
* and treating CoerceToDomain as immutable is outright dangerous. But we
|
|
* have done so historically, and changing this would probably cause more
|
|
* problems than it would fix. In practice, if you have a non-immutable
|
|
* domain constraint you are in for pain anyhow.
|
|
*/
|
|
|
|
/* Recurse to check arguments */
|
|
if (IsA(node, Query))
|
|
{
|
|
/* Recurse into subselects */
|
|
return query_tree_walker((Query *) node,
|
|
contain_mutable_functions_walker,
|
|
context, 0);
|
|
}
|
|
return expression_tree_walker(node, contain_mutable_functions_walker,
|
|
context);
|
|
}
|
|
|
|
|
|
/*****************************************************************************
|
|
* Check clauses for volatile functions
|
|
*****************************************************************************/
|
|
|
|
/*
|
|
* contain_volatile_functions
|
|
* Recursively search for volatile functions within a clause.
|
|
*
|
|
* Returns true if any volatile function (or operator implemented by a
|
|
* volatile function) is found. This test prevents, for example,
|
|
* invalid conversions of volatile expressions into indexscan quals.
|
|
*
|
|
* We will recursively look into Query nodes (i.e., SubLink sub-selects)
|
|
* but not into SubPlans. This is a bit odd, but intentional. If we are
|
|
* looking at a SubLink, we are probably deciding whether a query tree
|
|
* transformation is safe, and a contained sub-select should affect that;
|
|
* for example, duplicating a sub-select containing a volatile function
|
|
* would be bad. However, once we've got to the stage of having SubPlans,
|
|
* subsequent planning need not consider volatility within those, since
|
|
* the executor won't change its evaluation rules for a SubPlan based on
|
|
* volatility.
|
|
*/
|
|
bool
|
|
contain_volatile_functions(Node *clause)
|
|
{
|
|
return contain_volatile_functions_walker(clause, NULL);
|
|
}
|
|
|
|
static bool
|
|
contain_volatile_functions_checker(Oid func_id, void *context)
|
|
{
|
|
return (func_volatile(func_id) == PROVOLATILE_VOLATILE);
|
|
}
|
|
|
|
static bool
|
|
contain_volatile_functions_walker(Node *node, void *context)
|
|
{
|
|
if (node == NULL)
|
|
return false;
|
|
/* Check for volatile functions in node itself */
|
|
if (check_functions_in_node(node, contain_volatile_functions_checker,
|
|
context))
|
|
return true;
|
|
|
|
if (IsA(node, NextValueExpr))
|
|
{
|
|
/* NextValueExpr is volatile */
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* See notes in contain_mutable_functions_walker about why we treat
|
|
* MinMaxExpr, XmlExpr, and CoerceToDomain as immutable, while
|
|
* SQLValueFunction is stable. Hence, none of them are of interest here.
|
|
*/
|
|
|
|
/* Recurse to check arguments */
|
|
if (IsA(node, Query))
|
|
{
|
|
/* Recurse into subselects */
|
|
return query_tree_walker((Query *) node,
|
|
contain_volatile_functions_walker,
|
|
context, 0);
|
|
}
|
|
return expression_tree_walker(node, contain_volatile_functions_walker,
|
|
context);
|
|
}
|
|
|
|
/*
|
|
* Special purpose version of contain_volatile_functions() for use in COPY:
|
|
* ignore nextval(), but treat all other functions normally.
|
|
*/
|
|
bool
|
|
contain_volatile_functions_not_nextval(Node *clause)
|
|
{
|
|
return contain_volatile_functions_not_nextval_walker(clause, NULL);
|
|
}
|
|
|
|
static bool
|
|
contain_volatile_functions_not_nextval_checker(Oid func_id, void *context)
|
|
{
|
|
return (func_id != F_NEXTVAL_OID &&
|
|
func_volatile(func_id) == PROVOLATILE_VOLATILE);
|
|
}
|
|
|
|
static bool
|
|
contain_volatile_functions_not_nextval_walker(Node *node, void *context)
|
|
{
|
|
if (node == NULL)
|
|
return false;
|
|
/* Check for volatile functions in node itself */
|
|
if (check_functions_in_node(node,
|
|
contain_volatile_functions_not_nextval_checker,
|
|
context))
|
|
return true;
|
|
|
|
/*
|
|
* See notes in contain_mutable_functions_walker about why we treat
|
|
* MinMaxExpr, XmlExpr, and CoerceToDomain as immutable, while
|
|
* SQLValueFunction is stable. Hence, none of them are of interest here.
|
|
* Also, since we're intentionally ignoring nextval(), presumably we
|
|
* should ignore NextValueExpr.
|
|
*/
|
|
|
|
/* Recurse to check arguments */
|
|
if (IsA(node, Query))
|
|
{
|
|
/* Recurse into subselects */
|
|
return query_tree_walker((Query *) node,
|
|
contain_volatile_functions_not_nextval_walker,
|
|
context, 0);
|
|
}
|
|
return expression_tree_walker(node,
|
|
contain_volatile_functions_not_nextval_walker,
|
|
context);
|
|
}
|
|
|
|
|
|
/*****************************************************************************
|
|
* Check queries for parallel unsafe and/or restricted constructs
|
|
*****************************************************************************/
|
|
|
|
/*
|
|
* max_parallel_hazard
|
|
* Find the worst parallel-hazard level in the given query
|
|
*
|
|
* Returns the worst function hazard property (the earliest in this list:
|
|
* PROPARALLEL_UNSAFE, PROPARALLEL_RESTRICTED, PROPARALLEL_SAFE) that can
|
|
* be found in the given parsetree. We use this to find out whether the query
|
|
* can be parallelized at all. The caller will also save the result in
|
|
* PlannerGlobal so as to short-circuit checks of portions of the querytree
|
|
* later, in the common case where everything is SAFE.
|
|
*/
|
|
char
|
|
max_parallel_hazard(Query *parse)
|
|
{
|
|
max_parallel_hazard_context context;
|
|
|
|
context.max_hazard = PROPARALLEL_SAFE;
|
|
context.max_interesting = PROPARALLEL_UNSAFE;
|
|
context.safe_param_ids = NIL;
|
|
(void) max_parallel_hazard_walker((Node *) parse, &context);
|
|
return context.max_hazard;
|
|
}
|
|
|
|
/*
|
|
* is_parallel_safe
|
|
* Detect whether the given expr contains only parallel-safe functions
|
|
*
|
|
* root->glob->maxParallelHazard must previously have been set to the
|
|
* result of max_parallel_hazard() on the whole query.
|
|
*/
|
|
bool
|
|
is_parallel_safe(PlannerInfo *root, Node *node)
|
|
{
|
|
max_parallel_hazard_context context;
|
|
PlannerInfo *proot;
|
|
ListCell *l;
|
|
|
|
/*
|
|
* Even if the original querytree contained nothing unsafe, we need to
|
|
* search the expression if we have generated any PARAM_EXEC Params while
|
|
* planning, because those are parallel-restricted and there might be one
|
|
* in this expression. But otherwise we don't need to look.
|
|
*/
|
|
if (root->glob->maxParallelHazard == PROPARALLEL_SAFE &&
|
|
root->glob->paramExecTypes == NIL)
|
|
return true;
|
|
/* Else use max_parallel_hazard's search logic, but stop on RESTRICTED */
|
|
context.max_hazard = PROPARALLEL_SAFE;
|
|
context.max_interesting = PROPARALLEL_RESTRICTED;
|
|
context.safe_param_ids = NIL;
|
|
|
|
/*
|
|
* The params that refer to the same or parent query level are considered
|
|
* parallel-safe. The idea is that we compute such params at Gather or
|
|
* Gather Merge node and pass their value to workers.
|
|
*/
|
|
for (proot = root; proot != NULL; proot = proot->parent_root)
|
|
{
|
|
foreach(l, proot->init_plans)
|
|
{
|
|
SubPlan *initsubplan = (SubPlan *) lfirst(l);
|
|
|
|
context.safe_param_ids = list_concat(context.safe_param_ids,
|
|
initsubplan->setParam);
|
|
}
|
|
}
|
|
|
|
return !max_parallel_hazard_walker(node, &context);
|
|
}
|
|
|
|
/* core logic for all parallel-hazard checks */
|
|
static bool
|
|
max_parallel_hazard_test(char proparallel, max_parallel_hazard_context *context)
|
|
{
|
|
switch (proparallel)
|
|
{
|
|
case PROPARALLEL_SAFE:
|
|
/* nothing to see here, move along */
|
|
break;
|
|
case PROPARALLEL_RESTRICTED:
|
|
/* increase max_hazard to RESTRICTED */
|
|
Assert(context->max_hazard != PROPARALLEL_UNSAFE);
|
|
context->max_hazard = proparallel;
|
|
/* done if we are not expecting any unsafe functions */
|
|
if (context->max_interesting == proparallel)
|
|
return true;
|
|
break;
|
|
case PROPARALLEL_UNSAFE:
|
|
context->max_hazard = proparallel;
|
|
/* we're always done at the first unsafe construct */
|
|
return true;
|
|
default:
|
|
elog(ERROR, "unrecognized proparallel value \"%c\"", proparallel);
|
|
break;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/* check_functions_in_node callback */
|
|
static bool
|
|
max_parallel_hazard_checker(Oid func_id, void *context)
|
|
{
|
|
return max_parallel_hazard_test(func_parallel(func_id),
|
|
(max_parallel_hazard_context *) context);
|
|
}
|
|
|
|
static bool
|
|
max_parallel_hazard_walker(Node *node, max_parallel_hazard_context *context)
|
|
{
|
|
if (node == NULL)
|
|
return false;
|
|
|
|
/* Check for hazardous functions in node itself */
|
|
if (check_functions_in_node(node, max_parallel_hazard_checker,
|
|
context))
|
|
return true;
|
|
|
|
/*
|
|
* It should be OK to treat MinMaxExpr as parallel-safe, since btree
|
|
* opclass support functions are generally parallel-safe. XmlExpr is a
|
|
* bit more dubious but we can probably get away with it. We err on the
|
|
* side of caution by treating CoerceToDomain as parallel-restricted.
|
|
* (Note: in principle that's wrong because a domain constraint could
|
|
* contain a parallel-unsafe function; but useful constraints probably
|
|
* never would have such, and assuming they do would cripple use of
|
|
* parallel query in the presence of domain types.) SQLValueFunction
|
|
* should be safe in all cases. NextValueExpr is parallel-unsafe.
|
|
*/
|
|
if (IsA(node, CoerceToDomain))
|
|
{
|
|
if (max_parallel_hazard_test(PROPARALLEL_RESTRICTED, context))
|
|
return true;
|
|
}
|
|
|
|
else if (IsA(node, NextValueExpr))
|
|
{
|
|
if (max_parallel_hazard_test(PROPARALLEL_UNSAFE, context))
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Treat window functions as parallel-restricted because we aren't sure
|
|
* whether the input row ordering is fully deterministic, and the output
|
|
* of window functions might vary across workers if not. (In some cases,
|
|
* like where the window frame orders by a primary key, we could relax
|
|
* this restriction. But it doesn't currently seem worth expending extra
|
|
* effort to do so.)
|
|
*/
|
|
else if (IsA(node, WindowFunc))
|
|
{
|
|
if (max_parallel_hazard_test(PROPARALLEL_RESTRICTED, context))
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* As a notational convenience for callers, look through RestrictInfo.
|
|
*/
|
|
else if (IsA(node, RestrictInfo))
|
|
{
|
|
RestrictInfo *rinfo = (RestrictInfo *) node;
|
|
|
|
return max_parallel_hazard_walker((Node *) rinfo->clause, context);
|
|
}
|
|
|
|
/*
|
|
* Really we should not see SubLink during a max_interesting == restricted
|
|
* scan, but if we do, return true.
|
|
*/
|
|
else if (IsA(node, SubLink))
|
|
{
|
|
if (max_parallel_hazard_test(PROPARALLEL_RESTRICTED, context))
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Only parallel-safe SubPlans can be sent to workers. Within the
|
|
* testexpr of the SubPlan, Params representing the output columns of the
|
|
* subplan can be treated as parallel-safe, so temporarily add their IDs
|
|
* to the safe_param_ids list while examining the testexpr.
|
|
*/
|
|
else if (IsA(node, SubPlan))
|
|
{
|
|
SubPlan *subplan = (SubPlan *) node;
|
|
List *save_safe_param_ids;
|
|
|
|
if (!subplan->parallel_safe &&
|
|
max_parallel_hazard_test(PROPARALLEL_RESTRICTED, context))
|
|
return true;
|
|
save_safe_param_ids = context->safe_param_ids;
|
|
context->safe_param_ids = list_concat_copy(context->safe_param_ids,
|
|
subplan->paramIds);
|
|
if (max_parallel_hazard_walker(subplan->testexpr, context))
|
|
return true; /* no need to restore safe_param_ids */
|
|
list_free(context->safe_param_ids);
|
|
context->safe_param_ids = save_safe_param_ids;
|
|
/* we must also check args, but no special Param treatment there */
|
|
if (max_parallel_hazard_walker((Node *) subplan->args, context))
|
|
return true;
|
|
/* don't want to recurse normally, so we're done */
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* We can't pass Params to workers at the moment either, so they are also
|
|
* parallel-restricted, unless they are PARAM_EXTERN Params or are
|
|
* PARAM_EXEC Params listed in safe_param_ids, meaning they could be
|
|
* either generated within workers or can be computed by the leader and
|
|
* then their value can be passed to workers.
|
|
*/
|
|
else if (IsA(node, Param))
|
|
{
|
|
Param *param = (Param *) node;
|
|
|
|
if (param->paramkind == PARAM_EXTERN)
|
|
return false;
|
|
|
|
if (param->paramkind != PARAM_EXEC ||
|
|
!list_member_int(context->safe_param_ids, param->paramid))
|
|
{
|
|
if (max_parallel_hazard_test(PROPARALLEL_RESTRICTED, context))
|
|
return true;
|
|
}
|
|
return false; /* nothing to recurse to */
|
|
}
|
|
|
|
/*
|
|
* When we're first invoked on a completely unplanned tree, we must
|
|
* recurse into subqueries so to as to locate parallel-unsafe constructs
|
|
* anywhere in the tree.
|
|
*/
|
|
else if (IsA(node, Query))
|
|
{
|
|
Query *query = (Query *) node;
|
|
|
|
/* SELECT FOR UPDATE/SHARE must be treated as unsafe */
|
|
if (query->rowMarks != NULL)
|
|
{
|
|
context->max_hazard = PROPARALLEL_UNSAFE;
|
|
return true;
|
|
}
|
|
|
|
/* Recurse into subselects */
|
|
return query_tree_walker(query,
|
|
max_parallel_hazard_walker,
|
|
context, 0);
|
|
}
|
|
|
|
/* Recurse to check arguments */
|
|
return expression_tree_walker(node,
|
|
max_parallel_hazard_walker,
|
|
context);
|
|
}
|
|
|
|
|
|
/*****************************************************************************
|
|
* Check clauses for nonstrict functions
|
|
*****************************************************************************/
|
|
|
|
/*
|
|
* contain_nonstrict_functions
|
|
* Recursively search for nonstrict functions within a clause.
|
|
*
|
|
* Returns true if any nonstrict construct is found --- ie, anything that
|
|
* could produce non-NULL output with a NULL input.
|
|
*
|
|
* The idea here is that the caller has verified that the expression contains
|
|
* one or more Var or Param nodes (as appropriate for the caller's need), and
|
|
* now wishes to prove that the expression result will be NULL if any of these
|
|
* inputs is NULL. If we return false, then the proof succeeded.
|
|
*/
|
|
bool
|
|
contain_nonstrict_functions(Node *clause)
|
|
{
|
|
return contain_nonstrict_functions_walker(clause, NULL);
|
|
}
|
|
|
|
static bool
|
|
contain_nonstrict_functions_checker(Oid func_id, void *context)
|
|
{
|
|
return !func_strict(func_id);
|
|
}
|
|
|
|
static bool
|
|
contain_nonstrict_functions_walker(Node *node, void *context)
|
|
{
|
|
if (node == NULL)
|
|
return false;
|
|
if (IsA(node, Aggref))
|
|
{
|
|
/* an aggregate could return non-null with null input */
|
|
return true;
|
|
}
|
|
if (IsA(node, GroupingFunc))
|
|
{
|
|
/*
|
|
* A GroupingFunc doesn't evaluate its arguments, and therefore must
|
|
* be treated as nonstrict.
|
|
*/
|
|
return true;
|
|
}
|
|
if (IsA(node, WindowFunc))
|
|
{
|
|
/* a window function could return non-null with null input */
|
|
return true;
|
|
}
|
|
if (IsA(node, SubscriptingRef))
|
|
{
|
|
/*
|
|
* subscripting assignment is nonstrict, but subscripting itself is
|
|
* strict
|
|
*/
|
|
if (((SubscriptingRef *) node)->refassgnexpr != NULL)
|
|
return true;
|
|
|
|
/* else fall through to check args */
|
|
}
|
|
if (IsA(node, DistinctExpr))
|
|
{
|
|
/* IS DISTINCT FROM is inherently non-strict */
|
|
return true;
|
|
}
|
|
if (IsA(node, NullIfExpr))
|
|
{
|
|
/* NULLIF is inherently non-strict */
|
|
return true;
|
|
}
|
|
if (IsA(node, BoolExpr))
|
|
{
|
|
BoolExpr *expr = (BoolExpr *) node;
|
|
|
|
switch (expr->boolop)
|
|
{
|
|
case AND_EXPR:
|
|
case OR_EXPR:
|
|
/* AND, OR are inherently non-strict */
|
|
return true;
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
if (IsA(node, SubLink))
|
|
{
|
|
/* In some cases a sublink might be strict, but in general not */
|
|
return true;
|
|
}
|
|
if (IsA(node, SubPlan))
|
|
return true;
|
|
if (IsA(node, AlternativeSubPlan))
|
|
return true;
|
|
if (IsA(node, FieldStore))
|
|
return true;
|
|
if (IsA(node, CoerceViaIO))
|
|
{
|
|
/*
|
|
* CoerceViaIO is strict regardless of whether the I/O functions are,
|
|
* so just go look at its argument; asking check_functions_in_node is
|
|
* useless expense and could deliver the wrong answer.
|
|
*/
|
|
return contain_nonstrict_functions_walker((Node *) ((CoerceViaIO *) node)->arg,
|
|
context);
|
|
}
|
|
if (IsA(node, ArrayCoerceExpr))
|
|
{
|
|
/*
|
|
* ArrayCoerceExpr is strict at the array level, regardless of what
|
|
* the per-element expression is; so we should ignore elemexpr and
|
|
* recurse only into the arg.
|
|
*/
|
|
return contain_nonstrict_functions_walker((Node *) ((ArrayCoerceExpr *) node)->arg,
|
|
context);
|
|
}
|
|
if (IsA(node, CaseExpr))
|
|
return true;
|
|
if (IsA(node, ArrayExpr))
|
|
return true;
|
|
if (IsA(node, RowExpr))
|
|
return true;
|
|
if (IsA(node, RowCompareExpr))
|
|
return true;
|
|
if (IsA(node, CoalesceExpr))
|
|
return true;
|
|
if (IsA(node, MinMaxExpr))
|
|
return true;
|
|
if (IsA(node, XmlExpr))
|
|
return true;
|
|
if (IsA(node, NullTest))
|
|
return true;
|
|
if (IsA(node, BooleanTest))
|
|
return true;
|
|
|
|
/* Check other function-containing nodes */
|
|
if (check_functions_in_node(node, contain_nonstrict_functions_checker,
|
|
context))
|
|
return true;
|
|
|
|
return expression_tree_walker(node, contain_nonstrict_functions_walker,
|
|
context);
|
|
}
|
|
|
|
/*****************************************************************************
|
|
* Check clauses for Params
|
|
*****************************************************************************/
|
|
|
|
/*
|
|
* contain_exec_param
|
|
* Recursively search for PARAM_EXEC Params within a clause.
|
|
*
|
|
* Returns true if the clause contains any PARAM_EXEC Param with a paramid
|
|
* appearing in the given list of Param IDs. Does not descend into
|
|
* subqueries!
|
|
*/
|
|
bool
|
|
contain_exec_param(Node *clause, List *param_ids)
|
|
{
|
|
return contain_exec_param_walker(clause, param_ids);
|
|
}
|
|
|
|
static bool
|
|
contain_exec_param_walker(Node *node, List *param_ids)
|
|
{
|
|
if (node == NULL)
|
|
return false;
|
|
if (IsA(node, Param))
|
|
{
|
|
Param *p = (Param *) node;
|
|
|
|
if (p->paramkind == PARAM_EXEC &&
|
|
list_member_int(param_ids, p->paramid))
|
|
return true;
|
|
}
|
|
return expression_tree_walker(node, contain_exec_param_walker, param_ids);
|
|
}
|
|
|
|
/*****************************************************************************
|
|
* Check clauses for context-dependent nodes
|
|
*****************************************************************************/
|
|
|
|
/*
|
|
* contain_context_dependent_node
|
|
* Recursively search for context-dependent nodes within a clause.
|
|
*
|
|
* CaseTestExpr nodes must appear directly within the corresponding CaseExpr,
|
|
* not nested within another one, or they'll see the wrong test value. If one
|
|
* appears "bare" in the arguments of a SQL function, then we can't inline the
|
|
* SQL function for fear of creating such a situation. The same applies for
|
|
* CaseTestExpr used within the elemexpr of an ArrayCoerceExpr.
|
|
*
|
|
* CoerceToDomainValue would have the same issue if domain CHECK expressions
|
|
* could get inlined into larger expressions, but presently that's impossible.
|
|
* Still, it might be allowed in future, or other node types with similar
|
|
* issues might get invented. So give this function a generic name, and set
|
|
* up the recursion state to allow multiple flag bits.
|
|
*/
|
|
static bool
|
|
contain_context_dependent_node(Node *clause)
|
|
{
|
|
int flags = 0;
|
|
|
|
return contain_context_dependent_node_walker(clause, &flags);
|
|
}
|
|
|
|
#define CCDN_CASETESTEXPR_OK 0x0001 /* CaseTestExpr okay here? */
|
|
|
|
static bool
|
|
contain_context_dependent_node_walker(Node *node, int *flags)
|
|
{
|
|
if (node == NULL)
|
|
return false;
|
|
if (IsA(node, CaseTestExpr))
|
|
return !(*flags & CCDN_CASETESTEXPR_OK);
|
|
else if (IsA(node, CaseExpr))
|
|
{
|
|
CaseExpr *caseexpr = (CaseExpr *) node;
|
|
|
|
/*
|
|
* If this CASE doesn't have a test expression, then it doesn't create
|
|
* a context in which CaseTestExprs should appear, so just fall
|
|
* through and treat it as a generic expression node.
|
|
*/
|
|
if (caseexpr->arg)
|
|
{
|
|
int save_flags = *flags;
|
|
bool res;
|
|
|
|
/*
|
|
* Note: in principle, we could distinguish the various sub-parts
|
|
* of a CASE construct and set the flag bit only for some of them,
|
|
* since we are only expecting CaseTestExprs to appear in the
|
|
* "expr" subtree of the CaseWhen nodes. But it doesn't really
|
|
* seem worth any extra code. If there are any bare CaseTestExprs
|
|
* elsewhere in the CASE, something's wrong already.
|
|
*/
|
|
*flags |= CCDN_CASETESTEXPR_OK;
|
|
res = expression_tree_walker(node,
|
|
contain_context_dependent_node_walker,
|
|
(void *) flags);
|
|
*flags = save_flags;
|
|
return res;
|
|
}
|
|
}
|
|
else if (IsA(node, ArrayCoerceExpr))
|
|
{
|
|
ArrayCoerceExpr *ac = (ArrayCoerceExpr *) node;
|
|
int save_flags;
|
|
bool res;
|
|
|
|
/* Check the array expression */
|
|
if (contain_context_dependent_node_walker((Node *) ac->arg, flags))
|
|
return true;
|
|
|
|
/* Check the elemexpr, which is allowed to contain CaseTestExpr */
|
|
save_flags = *flags;
|
|
*flags |= CCDN_CASETESTEXPR_OK;
|
|
res = contain_context_dependent_node_walker((Node *) ac->elemexpr,
|
|
flags);
|
|
*flags = save_flags;
|
|
return res;
|
|
}
|
|
return expression_tree_walker(node, contain_context_dependent_node_walker,
|
|
(void *) flags);
|
|
}
|
|
|
|
/*****************************************************************************
|
|
* Check clauses for Vars passed to non-leakproof functions
|
|
*****************************************************************************/
|
|
|
|
/*
|
|
* contain_leaked_vars
|
|
* Recursively scan a clause to discover whether it contains any Var
|
|
* nodes (of the current query level) that are passed as arguments to
|
|
* leaky functions.
|
|
*
|
|
* Returns true if the clause contains any non-leakproof functions that are
|
|
* passed Var nodes of the current query level, and which might therefore leak
|
|
* data. Such clauses must be applied after any lower-level security barrier
|
|
* clauses.
|
|
*/
|
|
bool
|
|
contain_leaked_vars(Node *clause)
|
|
{
|
|
return contain_leaked_vars_walker(clause, NULL);
|
|
}
|
|
|
|
static bool
|
|
contain_leaked_vars_checker(Oid func_id, void *context)
|
|
{
|
|
return !get_func_leakproof(func_id);
|
|
}
|
|
|
|
static bool
|
|
contain_leaked_vars_walker(Node *node, void *context)
|
|
{
|
|
if (node == NULL)
|
|
return false;
|
|
|
|
switch (nodeTag(node))
|
|
{
|
|
case T_Var:
|
|
case T_Const:
|
|
case T_Param:
|
|
case T_ArrayExpr:
|
|
case T_FieldSelect:
|
|
case T_FieldStore:
|
|
case T_NamedArgExpr:
|
|
case T_BoolExpr:
|
|
case T_RelabelType:
|
|
case T_CollateExpr:
|
|
case T_CaseExpr:
|
|
case T_CaseTestExpr:
|
|
case T_RowExpr:
|
|
case T_SQLValueFunction:
|
|
case T_NullTest:
|
|
case T_BooleanTest:
|
|
case T_NextValueExpr:
|
|
case T_List:
|
|
|
|
/*
|
|
* We know these node types don't contain function calls; but
|
|
* something further down in the node tree might.
|
|
*/
|
|
break;
|
|
|
|
case T_FuncExpr:
|
|
case T_OpExpr:
|
|
case T_DistinctExpr:
|
|
case T_NullIfExpr:
|
|
case T_ScalarArrayOpExpr:
|
|
case T_CoerceViaIO:
|
|
case T_ArrayCoerceExpr:
|
|
case T_SubscriptingRef:
|
|
|
|
/*
|
|
* If node contains a leaky function call, and there's any Var
|
|
* underneath it, reject.
|
|
*/
|
|
if (check_functions_in_node(node, contain_leaked_vars_checker,
|
|
context) &&
|
|
contain_var_clause(node))
|
|
return true;
|
|
break;
|
|
|
|
case T_RowCompareExpr:
|
|
{
|
|
/*
|
|
* It's worth special-casing this because a leaky comparison
|
|
* function only compromises one pair of row elements, which
|
|
* might not contain Vars while others do.
|
|
*/
|
|
RowCompareExpr *rcexpr = (RowCompareExpr *) node;
|
|
ListCell *opid;
|
|
ListCell *larg;
|
|
ListCell *rarg;
|
|
|
|
forthree(opid, rcexpr->opnos,
|
|
larg, rcexpr->largs,
|
|
rarg, rcexpr->rargs)
|
|
{
|
|
Oid funcid = get_opcode(lfirst_oid(opid));
|
|
|
|
if (!get_func_leakproof(funcid) &&
|
|
(contain_var_clause((Node *) lfirst(larg)) ||
|
|
contain_var_clause((Node *) lfirst(rarg))))
|
|
return true;
|
|
}
|
|
}
|
|
break;
|
|
|
|
case T_MinMaxExpr:
|
|
{
|
|
/*
|
|
* MinMaxExpr is leakproof if the comparison function it calls
|
|
* is leakproof.
|
|
*/
|
|
MinMaxExpr *minmaxexpr = (MinMaxExpr *) node;
|
|
TypeCacheEntry *typentry;
|
|
bool leakproof;
|
|
|
|
/* Look up the btree comparison function for the datatype */
|
|
typentry = lookup_type_cache(minmaxexpr->minmaxtype,
|
|
TYPECACHE_CMP_PROC);
|
|
if (OidIsValid(typentry->cmp_proc))
|
|
leakproof = get_func_leakproof(typentry->cmp_proc);
|
|
else
|
|
{
|
|
/*
|
|
* The executor will throw an error, but here we just
|
|
* treat the missing function as leaky.
|
|
*/
|
|
leakproof = false;
|
|
}
|
|
|
|
if (!leakproof &&
|
|
contain_var_clause((Node *) minmaxexpr->args))
|
|
return true;
|
|
}
|
|
break;
|
|
|
|
case T_CurrentOfExpr:
|
|
|
|
/*
|
|
* WHERE CURRENT OF doesn't contain leaky function calls.
|
|
* Moreover, it is essential that this is considered non-leaky,
|
|
* since the planner must always generate a TID scan when CURRENT
|
|
* OF is present -- cf. cost_tidscan.
|
|
*/
|
|
return false;
|
|
|
|
default:
|
|
|
|
/*
|
|
* If we don't recognize the node tag, assume it might be leaky.
|
|
* This prevents an unexpected security hole if someone adds a new
|
|
* node type that can call a function.
|
|
*/
|
|
return true;
|
|
}
|
|
return expression_tree_walker(node, contain_leaked_vars_walker,
|
|
context);
|
|
}
|
|
|
|
/*
|
|
* find_nonnullable_rels
|
|
* Determine which base rels are forced nonnullable by given clause.
|
|
*
|
|
* Returns the set of all Relids that are referenced in the clause in such
|
|
* a way that the clause cannot possibly return TRUE if any of these Relids
|
|
* is an all-NULL row. (It is OK to err on the side of conservatism; hence
|
|
* the analysis here is simplistic.)
|
|
*
|
|
* The semantics here are subtly different from contain_nonstrict_functions:
|
|
* that function is concerned with NULL results from arbitrary expressions,
|
|
* but here we assume that the input is a Boolean expression, and wish to
|
|
* see if NULL inputs will provably cause a FALSE-or-NULL result. We expect
|
|
* the expression to have been AND/OR flattened and converted to implicit-AND
|
|
* format.
|
|
*
|
|
* Note: this function is largely duplicative of find_nonnullable_vars().
|
|
* The reason not to simplify this function into a thin wrapper around
|
|
* find_nonnullable_vars() is that the tested conditions really are different:
|
|
* a clause like "t1.v1 IS NOT NULL OR t1.v2 IS NOT NULL" does not prove
|
|
* that either v1 or v2 can't be NULL, but it does prove that the t1 row
|
|
* as a whole can't be all-NULL. Also, the behavior for PHVs is different.
|
|
*
|
|
* top_level is true while scanning top-level AND/OR structure; here, showing
|
|
* the result is either FALSE or NULL is good enough. top_level is false when
|
|
* we have descended below a NOT or a strict function: now we must be able to
|
|
* prove that the subexpression goes to NULL.
|
|
*
|
|
* We don't use expression_tree_walker here because we don't want to descend
|
|
* through very many kinds of nodes; only the ones we can be sure are strict.
|
|
*/
|
|
Relids
|
|
find_nonnullable_rels(Node *clause)
|
|
{
|
|
return find_nonnullable_rels_walker(clause, true);
|
|
}
|
|
|
|
static Relids
|
|
find_nonnullable_rels_walker(Node *node, bool top_level)
|
|
{
|
|
Relids result = NULL;
|
|
ListCell *l;
|
|
|
|
if (node == NULL)
|
|
return NULL;
|
|
if (IsA(node, Var))
|
|
{
|
|
Var *var = (Var *) node;
|
|
|
|
if (var->varlevelsup == 0)
|
|
result = bms_make_singleton(var->varno);
|
|
}
|
|
else if (IsA(node, List))
|
|
{
|
|
/*
|
|
* At top level, we are examining an implicit-AND list: if any of the
|
|
* arms produces FALSE-or-NULL then the result is FALSE-or-NULL. If
|
|
* not at top level, we are examining the arguments of a strict
|
|
* function: if any of them produce NULL then the result of the
|
|
* function must be NULL. So in both cases, the set of nonnullable
|
|
* rels is the union of those found in the arms, and we pass down the
|
|
* top_level flag unmodified.
|
|
*/
|
|
foreach(l, (List *) node)
|
|
{
|
|
result = bms_join(result,
|
|
find_nonnullable_rels_walker(lfirst(l),
|
|
top_level));
|
|
}
|
|
}
|
|
else if (IsA(node, FuncExpr))
|
|
{
|
|
FuncExpr *expr = (FuncExpr *) node;
|
|
|
|
if (func_strict(expr->funcid))
|
|
result = find_nonnullable_rels_walker((Node *) expr->args, false);
|
|
}
|
|
else if (IsA(node, OpExpr))
|
|
{
|
|
OpExpr *expr = (OpExpr *) node;
|
|
|
|
set_opfuncid(expr);
|
|
if (func_strict(expr->opfuncid))
|
|
result = find_nonnullable_rels_walker((Node *) expr->args, false);
|
|
}
|
|
else if (IsA(node, ScalarArrayOpExpr))
|
|
{
|
|
ScalarArrayOpExpr *expr = (ScalarArrayOpExpr *) node;
|
|
|
|
if (is_strict_saop(expr, true))
|
|
result = find_nonnullable_rels_walker((Node *) expr->args, false);
|
|
}
|
|
else if (IsA(node, BoolExpr))
|
|
{
|
|
BoolExpr *expr = (BoolExpr *) node;
|
|
|
|
switch (expr->boolop)
|
|
{
|
|
case AND_EXPR:
|
|
/* At top level we can just recurse (to the List case) */
|
|
if (top_level)
|
|
{
|
|
result = find_nonnullable_rels_walker((Node *) expr->args,
|
|
top_level);
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Below top level, even if one arm produces NULL, the result
|
|
* could be FALSE (hence not NULL). However, if *all* the
|
|
* arms produce NULL then the result is NULL, so we can take
|
|
* the intersection of the sets of nonnullable rels, just as
|
|
* for OR. Fall through to share code.
|
|
*/
|
|
/* FALL THRU */
|
|
case OR_EXPR:
|
|
|
|
/*
|
|
* OR is strict if all of its arms are, so we can take the
|
|
* intersection of the sets of nonnullable rels for each arm.
|
|
* This works for both values of top_level.
|
|
*/
|
|
foreach(l, expr->args)
|
|
{
|
|
Relids subresult;
|
|
|
|
subresult = find_nonnullable_rels_walker(lfirst(l),
|
|
top_level);
|
|
if (result == NULL) /* first subresult? */
|
|
result = subresult;
|
|
else
|
|
result = bms_int_members(result, subresult);
|
|
|
|
/*
|
|
* If the intersection is empty, we can stop looking. This
|
|
* also justifies the test for first-subresult above.
|
|
*/
|
|
if (bms_is_empty(result))
|
|
break;
|
|
}
|
|
break;
|
|
case NOT_EXPR:
|
|
/* NOT will return null if its arg is null */
|
|
result = find_nonnullable_rels_walker((Node *) expr->args,
|
|
false);
|
|
break;
|
|
default:
|
|
elog(ERROR, "unrecognized boolop: %d", (int) expr->boolop);
|
|
break;
|
|
}
|
|
}
|
|
else if (IsA(node, RelabelType))
|
|
{
|
|
RelabelType *expr = (RelabelType *) node;
|
|
|
|
result = find_nonnullable_rels_walker((Node *) expr->arg, top_level);
|
|
}
|
|
else if (IsA(node, CoerceViaIO))
|
|
{
|
|
/* not clear this is useful, but it can't hurt */
|
|
CoerceViaIO *expr = (CoerceViaIO *) node;
|
|
|
|
result = find_nonnullable_rels_walker((Node *) expr->arg, top_level);
|
|
}
|
|
else if (IsA(node, ArrayCoerceExpr))
|
|
{
|
|
/* ArrayCoerceExpr is strict at the array level; ignore elemexpr */
|
|
ArrayCoerceExpr *expr = (ArrayCoerceExpr *) node;
|
|
|
|
result = find_nonnullable_rels_walker((Node *) expr->arg, top_level);
|
|
}
|
|
else if (IsA(node, ConvertRowtypeExpr))
|
|
{
|
|
/* not clear this is useful, but it can't hurt */
|
|
ConvertRowtypeExpr *expr = (ConvertRowtypeExpr *) node;
|
|
|
|
result = find_nonnullable_rels_walker((Node *) expr->arg, top_level);
|
|
}
|
|
else if (IsA(node, CollateExpr))
|
|
{
|
|
CollateExpr *expr = (CollateExpr *) node;
|
|
|
|
result = find_nonnullable_rels_walker((Node *) expr->arg, top_level);
|
|
}
|
|
else if (IsA(node, NullTest))
|
|
{
|
|
/* IS NOT NULL can be considered strict, but only at top level */
|
|
NullTest *expr = (NullTest *) node;
|
|
|
|
if (top_level && expr->nulltesttype == IS_NOT_NULL && !expr->argisrow)
|
|
result = find_nonnullable_rels_walker((Node *) expr->arg, false);
|
|
}
|
|
else if (IsA(node, BooleanTest))
|
|
{
|
|
/* Boolean tests that reject NULL are strict at top level */
|
|
BooleanTest *expr = (BooleanTest *) node;
|
|
|
|
if (top_level &&
|
|
(expr->booltesttype == IS_TRUE ||
|
|
expr->booltesttype == IS_FALSE ||
|
|
expr->booltesttype == IS_NOT_UNKNOWN))
|
|
result = find_nonnullable_rels_walker((Node *) expr->arg, false);
|
|
}
|
|
else if (IsA(node, PlaceHolderVar))
|
|
{
|
|
PlaceHolderVar *phv = (PlaceHolderVar *) node;
|
|
|
|
/*
|
|
* If the contained expression forces any rels non-nullable, so does
|
|
* the PHV.
|
|
*/
|
|
result = find_nonnullable_rels_walker((Node *) phv->phexpr, top_level);
|
|
|
|
/*
|
|
* If the PHV's syntactic scope is exactly one rel, it will be forced
|
|
* to be evaluated at that rel, and so it will behave like a Var of
|
|
* that rel: if the rel's entire output goes to null, so will the PHV.
|
|
* (If the syntactic scope is a join, we know that the PHV will go to
|
|
* null if the whole join does; but that is AND semantics while we
|
|
* need OR semantics for find_nonnullable_rels' result, so we can't do
|
|
* anything with the knowledge.)
|
|
*/
|
|
if (phv->phlevelsup == 0 &&
|
|
bms_membership(phv->phrels) == BMS_SINGLETON)
|
|
result = bms_add_members(result, phv->phrels);
|
|
}
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* find_nonnullable_vars
|
|
* Determine which Vars are forced nonnullable by given clause.
|
|
*
|
|
* Returns a list of all level-zero Vars that are referenced in the clause in
|
|
* such a way that the clause cannot possibly return TRUE if any of these Vars
|
|
* is NULL. (It is OK to err on the side of conservatism; hence the analysis
|
|
* here is simplistic.)
|
|
*
|
|
* The semantics here are subtly different from contain_nonstrict_functions:
|
|
* that function is concerned with NULL results from arbitrary expressions,
|
|
* but here we assume that the input is a Boolean expression, and wish to
|
|
* see if NULL inputs will provably cause a FALSE-or-NULL result. We expect
|
|
* the expression to have been AND/OR flattened and converted to implicit-AND
|
|
* format.
|
|
*
|
|
* The result is a palloc'd List, but we have not copied the member Var nodes.
|
|
* Also, we don't bother trying to eliminate duplicate entries.
|
|
*
|
|
* top_level is true while scanning top-level AND/OR structure; here, showing
|
|
* the result is either FALSE or NULL is good enough. top_level is false when
|
|
* we have descended below a NOT or a strict function: now we must be able to
|
|
* prove that the subexpression goes to NULL.
|
|
*
|
|
* We don't use expression_tree_walker here because we don't want to descend
|
|
* through very many kinds of nodes; only the ones we can be sure are strict.
|
|
*/
|
|
List *
|
|
find_nonnullable_vars(Node *clause)
|
|
{
|
|
return find_nonnullable_vars_walker(clause, true);
|
|
}
|
|
|
|
static List *
|
|
find_nonnullable_vars_walker(Node *node, bool top_level)
|
|
{
|
|
List *result = NIL;
|
|
ListCell *l;
|
|
|
|
if (node == NULL)
|
|
return NIL;
|
|
if (IsA(node, Var))
|
|
{
|
|
Var *var = (Var *) node;
|
|
|
|
if (var->varlevelsup == 0)
|
|
result = list_make1(var);
|
|
}
|
|
else if (IsA(node, List))
|
|
{
|
|
/*
|
|
* At top level, we are examining an implicit-AND list: if any of the
|
|
* arms produces FALSE-or-NULL then the result is FALSE-or-NULL. If
|
|
* not at top level, we are examining the arguments of a strict
|
|
* function: if any of them produce NULL then the result of the
|
|
* function must be NULL. So in both cases, the set of nonnullable
|
|
* vars is the union of those found in the arms, and we pass down the
|
|
* top_level flag unmodified.
|
|
*/
|
|
foreach(l, (List *) node)
|
|
{
|
|
result = list_concat(result,
|
|
find_nonnullable_vars_walker(lfirst(l),
|
|
top_level));
|
|
}
|
|
}
|
|
else if (IsA(node, FuncExpr))
|
|
{
|
|
FuncExpr *expr = (FuncExpr *) node;
|
|
|
|
if (func_strict(expr->funcid))
|
|
result = find_nonnullable_vars_walker((Node *) expr->args, false);
|
|
}
|
|
else if (IsA(node, OpExpr))
|
|
{
|
|
OpExpr *expr = (OpExpr *) node;
|
|
|
|
set_opfuncid(expr);
|
|
if (func_strict(expr->opfuncid))
|
|
result = find_nonnullable_vars_walker((Node *) expr->args, false);
|
|
}
|
|
else if (IsA(node, ScalarArrayOpExpr))
|
|
{
|
|
ScalarArrayOpExpr *expr = (ScalarArrayOpExpr *) node;
|
|
|
|
if (is_strict_saop(expr, true))
|
|
result = find_nonnullable_vars_walker((Node *) expr->args, false);
|
|
}
|
|
else if (IsA(node, BoolExpr))
|
|
{
|
|
BoolExpr *expr = (BoolExpr *) node;
|
|
|
|
switch (expr->boolop)
|
|
{
|
|
case AND_EXPR:
|
|
/* At top level we can just recurse (to the List case) */
|
|
if (top_level)
|
|
{
|
|
result = find_nonnullable_vars_walker((Node *) expr->args,
|
|
top_level);
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Below top level, even if one arm produces NULL, the result
|
|
* could be FALSE (hence not NULL). However, if *all* the
|
|
* arms produce NULL then the result is NULL, so we can take
|
|
* the intersection of the sets of nonnullable vars, just as
|
|
* for OR. Fall through to share code.
|
|
*/
|
|
/* FALL THRU */
|
|
case OR_EXPR:
|
|
|
|
/*
|
|
* OR is strict if all of its arms are, so we can take the
|
|
* intersection of the sets of nonnullable vars for each arm.
|
|
* This works for both values of top_level.
|
|
*/
|
|
foreach(l, expr->args)
|
|
{
|
|
List *subresult;
|
|
|
|
subresult = find_nonnullable_vars_walker(lfirst(l),
|
|
top_level);
|
|
if (result == NIL) /* first subresult? */
|
|
result = subresult;
|
|
else
|
|
result = list_intersection(result, subresult);
|
|
|
|
/*
|
|
* If the intersection is empty, we can stop looking. This
|
|
* also justifies the test for first-subresult above.
|
|
*/
|
|
if (result == NIL)
|
|
break;
|
|
}
|
|
break;
|
|
case NOT_EXPR:
|
|
/* NOT will return null if its arg is null */
|
|
result = find_nonnullable_vars_walker((Node *) expr->args,
|
|
false);
|
|
break;
|
|
default:
|
|
elog(ERROR, "unrecognized boolop: %d", (int) expr->boolop);
|
|
break;
|
|
}
|
|
}
|
|
else if (IsA(node, RelabelType))
|
|
{
|
|
RelabelType *expr = (RelabelType *) node;
|
|
|
|
result = find_nonnullable_vars_walker((Node *) expr->arg, top_level);
|
|
}
|
|
else if (IsA(node, CoerceViaIO))
|
|
{
|
|
/* not clear this is useful, but it can't hurt */
|
|
CoerceViaIO *expr = (CoerceViaIO *) node;
|
|
|
|
result = find_nonnullable_vars_walker((Node *) expr->arg, false);
|
|
}
|
|
else if (IsA(node, ArrayCoerceExpr))
|
|
{
|
|
/* ArrayCoerceExpr is strict at the array level; ignore elemexpr */
|
|
ArrayCoerceExpr *expr = (ArrayCoerceExpr *) node;
|
|
|
|
result = find_nonnullable_vars_walker((Node *) expr->arg, top_level);
|
|
}
|
|
else if (IsA(node, ConvertRowtypeExpr))
|
|
{
|
|
/* not clear this is useful, but it can't hurt */
|
|
ConvertRowtypeExpr *expr = (ConvertRowtypeExpr *) node;
|
|
|
|
result = find_nonnullable_vars_walker((Node *) expr->arg, top_level);
|
|
}
|
|
else if (IsA(node, CollateExpr))
|
|
{
|
|
CollateExpr *expr = (CollateExpr *) node;
|
|
|
|
result = find_nonnullable_vars_walker((Node *) expr->arg, top_level);
|
|
}
|
|
else if (IsA(node, NullTest))
|
|
{
|
|
/* IS NOT NULL can be considered strict, but only at top level */
|
|
NullTest *expr = (NullTest *) node;
|
|
|
|
if (top_level && expr->nulltesttype == IS_NOT_NULL && !expr->argisrow)
|
|
result = find_nonnullable_vars_walker((Node *) expr->arg, false);
|
|
}
|
|
else if (IsA(node, BooleanTest))
|
|
{
|
|
/* Boolean tests that reject NULL are strict at top level */
|
|
BooleanTest *expr = (BooleanTest *) node;
|
|
|
|
if (top_level &&
|
|
(expr->booltesttype == IS_TRUE ||
|
|
expr->booltesttype == IS_FALSE ||
|
|
expr->booltesttype == IS_NOT_UNKNOWN))
|
|
result = find_nonnullable_vars_walker((Node *) expr->arg, false);
|
|
}
|
|
else if (IsA(node, PlaceHolderVar))
|
|
{
|
|
PlaceHolderVar *phv = (PlaceHolderVar *) node;
|
|
|
|
result = find_nonnullable_vars_walker((Node *) phv->phexpr, top_level);
|
|
}
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* find_forced_null_vars
|
|
* Determine which Vars must be NULL for the given clause to return TRUE.
|
|
*
|
|
* This is the complement of find_nonnullable_vars: find the level-zero Vars
|
|
* that must be NULL for the clause to return TRUE. (It is OK to err on the
|
|
* side of conservatism; hence the analysis here is simplistic. In fact,
|
|
* we only detect simple "var IS NULL" tests at the top level.)
|
|
*
|
|
* The result is a palloc'd List, but we have not copied the member Var nodes.
|
|
* Also, we don't bother trying to eliminate duplicate entries.
|
|
*/
|
|
List *
|
|
find_forced_null_vars(Node *node)
|
|
{
|
|
List *result = NIL;
|
|
Var *var;
|
|
ListCell *l;
|
|
|
|
if (node == NULL)
|
|
return NIL;
|
|
/* Check single-clause cases using subroutine */
|
|
var = find_forced_null_var(node);
|
|
if (var)
|
|
{
|
|
result = list_make1(var);
|
|
}
|
|
/* Otherwise, handle AND-conditions */
|
|
else if (IsA(node, List))
|
|
{
|
|
/*
|
|
* At top level, we are examining an implicit-AND list: if any of the
|
|
* arms produces FALSE-or-NULL then the result is FALSE-or-NULL.
|
|
*/
|
|
foreach(l, (List *) node)
|
|
{
|
|
result = list_concat(result,
|
|
find_forced_null_vars(lfirst(l)));
|
|
}
|
|
}
|
|
else if (IsA(node, BoolExpr))
|
|
{
|
|
BoolExpr *expr = (BoolExpr *) node;
|
|
|
|
/*
|
|
* We don't bother considering the OR case, because it's fairly
|
|
* unlikely anyone would write "v1 IS NULL OR v1 IS NULL". Likewise,
|
|
* the NOT case isn't worth expending code on.
|
|
*/
|
|
if (expr->boolop == AND_EXPR)
|
|
{
|
|
/* At top level we can just recurse (to the List case) */
|
|
result = find_forced_null_vars((Node *) expr->args);
|
|
}
|
|
}
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* find_forced_null_var
|
|
* Return the Var forced null by the given clause, or NULL if it's
|
|
* not an IS NULL-type clause. For success, the clause must enforce
|
|
* *only* nullness of the particular Var, not any other conditions.
|
|
*
|
|
* This is just the single-clause case of find_forced_null_vars(), without
|
|
* any allowance for AND conditions. It's used by initsplan.c on individual
|
|
* qual clauses. The reason for not just applying find_forced_null_vars()
|
|
* is that if an AND of an IS NULL clause with something else were to somehow
|
|
* survive AND/OR flattening, initsplan.c might get fooled into discarding
|
|
* the whole clause when only the IS NULL part of it had been proved redundant.
|
|
*/
|
|
Var *
|
|
find_forced_null_var(Node *node)
|
|
{
|
|
if (node == NULL)
|
|
return NULL;
|
|
if (IsA(node, NullTest))
|
|
{
|
|
/* check for var IS NULL */
|
|
NullTest *expr = (NullTest *) node;
|
|
|
|
if (expr->nulltesttype == IS_NULL && !expr->argisrow)
|
|
{
|
|
Var *var = (Var *) expr->arg;
|
|
|
|
if (var && IsA(var, Var) &&
|
|
var->varlevelsup == 0)
|
|
return var;
|
|
}
|
|
}
|
|
else if (IsA(node, BooleanTest))
|
|
{
|
|
/* var IS UNKNOWN is equivalent to var IS NULL */
|
|
BooleanTest *expr = (BooleanTest *) node;
|
|
|
|
if (expr->booltesttype == IS_UNKNOWN)
|
|
{
|
|
Var *var = (Var *) expr->arg;
|
|
|
|
if (var && IsA(var, Var) &&
|
|
var->varlevelsup == 0)
|
|
return var;
|
|
}
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Can we treat a ScalarArrayOpExpr as strict?
|
|
*
|
|
* If "falseOK" is true, then a "false" result can be considered strict,
|
|
* else we need to guarantee an actual NULL result for NULL input.
|
|
*
|
|
* "foo op ALL array" is strict if the op is strict *and* we can prove
|
|
* that the array input isn't an empty array. We can check that
|
|
* for the cases of an array constant and an ARRAY[] construct.
|
|
*
|
|
* "foo op ANY array" is strict in the falseOK sense if the op is strict.
|
|
* If not falseOK, the test is the same as for "foo op ALL array".
|
|
*/
|
|
static bool
|
|
is_strict_saop(ScalarArrayOpExpr *expr, bool falseOK)
|
|
{
|
|
Node *rightop;
|
|
|
|
/* The contained operator must be strict. */
|
|
set_sa_opfuncid(expr);
|
|
if (!func_strict(expr->opfuncid))
|
|
return false;
|
|
/* If ANY and falseOK, that's all we need to check. */
|
|
if (expr->useOr && falseOK)
|
|
return true;
|
|
/* Else, we have to see if the array is provably non-empty. */
|
|
Assert(list_length(expr->args) == 2);
|
|
rightop = (Node *) lsecond(expr->args);
|
|
if (rightop && IsA(rightop, Const))
|
|
{
|
|
Datum arraydatum = ((Const *) rightop)->constvalue;
|
|
bool arrayisnull = ((Const *) rightop)->constisnull;
|
|
ArrayType *arrayval;
|
|
int nitems;
|
|
|
|
if (arrayisnull)
|
|
return false;
|
|
arrayval = DatumGetArrayTypeP(arraydatum);
|
|
nitems = ArrayGetNItems(ARR_NDIM(arrayval), ARR_DIMS(arrayval));
|
|
if (nitems > 0)
|
|
return true;
|
|
}
|
|
else if (rightop && IsA(rightop, ArrayExpr))
|
|
{
|
|
ArrayExpr *arrayexpr = (ArrayExpr *) rightop;
|
|
|
|
if (arrayexpr->elements != NIL && !arrayexpr->multidims)
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
|
|
/*****************************************************************************
|
|
* Check for "pseudo-constant" clauses
|
|
*****************************************************************************/
|
|
|
|
/*
|
|
* is_pseudo_constant_clause
|
|
* Detect whether an expression is "pseudo constant", ie, it contains no
|
|
* variables of the current query level and no uses of volatile functions.
|
|
* Such an expr is not necessarily a true constant: it can still contain
|
|
* Params and outer-level Vars, not to mention functions whose results
|
|
* may vary from one statement to the next. However, the expr's value
|
|
* will be constant over any one scan of the current query, so it can be
|
|
* used as, eg, an indexscan key. (Actually, the condition for indexscan
|
|
* keys is weaker than this; see is_pseudo_constant_for_index().)
|
|
*
|
|
* CAUTION: this function omits to test for one very important class of
|
|
* not-constant expressions, namely aggregates (Aggrefs). In current usage
|
|
* this is only applied to WHERE clauses and so a check for Aggrefs would be
|
|
* a waste of cycles; but be sure to also check contain_agg_clause() if you
|
|
* want to know about pseudo-constness in other contexts. The same goes
|
|
* for window functions (WindowFuncs).
|
|
*/
|
|
bool
|
|
is_pseudo_constant_clause(Node *clause)
|
|
{
|
|
/*
|
|
* We could implement this check in one recursive scan. But since the
|
|
* check for volatile functions is both moderately expensive and unlikely
|
|
* to fail, it seems better to look for Vars first and only check for
|
|
* volatile functions if we find no Vars.
|
|
*/
|
|
if (!contain_var_clause(clause) &&
|
|
!contain_volatile_functions(clause))
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* is_pseudo_constant_clause_relids
|
|
* Same as above, except caller already has available the var membership
|
|
* of the expression; this lets us avoid the contain_var_clause() scan.
|
|
*/
|
|
bool
|
|
is_pseudo_constant_clause_relids(Node *clause, Relids relids)
|
|
{
|
|
if (bms_is_empty(relids) &&
|
|
!contain_volatile_functions(clause))
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
|
|
/*****************************************************************************
|
|
* *
|
|
* General clause-manipulating routines *
|
|
* *
|
|
*****************************************************************************/
|
|
|
|
/*
|
|
* NumRelids
|
|
* (formerly clause_relids)
|
|
*
|
|
* Returns the number of different relations referenced in 'clause'.
|
|
*/
|
|
int
|
|
NumRelids(Node *clause)
|
|
{
|
|
Relids varnos = pull_varnos(clause);
|
|
int result = bms_num_members(varnos);
|
|
|
|
bms_free(varnos);
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* CommuteOpExpr: commute a binary operator clause
|
|
*
|
|
* XXX the clause is destructively modified!
|
|
*/
|
|
void
|
|
CommuteOpExpr(OpExpr *clause)
|
|
{
|
|
Oid opoid;
|
|
Node *temp;
|
|
|
|
/* Sanity checks: caller is at fault if these fail */
|
|
if (!is_opclause(clause) ||
|
|
list_length(clause->args) != 2)
|
|
elog(ERROR, "cannot commute non-binary-operator clause");
|
|
|
|
opoid = get_commutator(clause->opno);
|
|
|
|
if (!OidIsValid(opoid))
|
|
elog(ERROR, "could not find commutator for operator %u",
|
|
clause->opno);
|
|
|
|
/*
|
|
* modify the clause in-place!
|
|
*/
|
|
clause->opno = opoid;
|
|
clause->opfuncid = InvalidOid;
|
|
/* opresulttype, opretset, opcollid, inputcollid need not change */
|
|
|
|
temp = linitial(clause->args);
|
|
linitial(clause->args) = lsecond(clause->args);
|
|
lsecond(clause->args) = temp;
|
|
}
|
|
|
|
/*
|
|
* Helper for eval_const_expressions: check that datatype of an attribute
|
|
* is still what it was when the expression was parsed. This is needed to
|
|
* guard against improper simplification after ALTER COLUMN TYPE. (XXX we
|
|
* may well need to make similar checks elsewhere?)
|
|
*
|
|
* rowtypeid may come from a whole-row Var, and therefore it can be a domain
|
|
* over composite, but for this purpose we only care about checking the type
|
|
* of a contained field.
|
|
*/
|
|
static bool
|
|
rowtype_field_matches(Oid rowtypeid, int fieldnum,
|
|
Oid expectedtype, int32 expectedtypmod,
|
|
Oid expectedcollation)
|
|
{
|
|
TupleDesc tupdesc;
|
|
Form_pg_attribute attr;
|
|
|
|
/* No issue for RECORD, since there is no way to ALTER such a type */
|
|
if (rowtypeid == RECORDOID)
|
|
return true;
|
|
tupdesc = lookup_rowtype_tupdesc_domain(rowtypeid, -1, false);
|
|
if (fieldnum <= 0 || fieldnum > tupdesc->natts)
|
|
{
|
|
ReleaseTupleDesc(tupdesc);
|
|
return false;
|
|
}
|
|
attr = TupleDescAttr(tupdesc, fieldnum - 1);
|
|
if (attr->attisdropped ||
|
|
attr->atttypid != expectedtype ||
|
|
attr->atttypmod != expectedtypmod ||
|
|
attr->attcollation != expectedcollation)
|
|
{
|
|
ReleaseTupleDesc(tupdesc);
|
|
return false;
|
|
}
|
|
ReleaseTupleDesc(tupdesc);
|
|
return true;
|
|
}
|
|
|
|
|
|
/*--------------------
|
|
* eval_const_expressions
|
|
*
|
|
* Reduce any recognizably constant subexpressions of the given
|
|
* expression tree, for example "2 + 2" => "4". More interestingly,
|
|
* we can reduce certain boolean expressions even when they contain
|
|
* non-constant subexpressions: "x OR true" => "true" no matter what
|
|
* the subexpression x is. (XXX We assume that no such subexpression
|
|
* will have important side-effects, which is not necessarily a good
|
|
* assumption in the presence of user-defined functions; do we need a
|
|
* pg_proc flag that prevents discarding the execution of a function?)
|
|
*
|
|
* We do understand that certain functions may deliver non-constant
|
|
* results even with constant inputs, "nextval()" being the classic
|
|
* example. Functions that are not marked "immutable" in pg_proc
|
|
* will not be pre-evaluated here, although we will reduce their
|
|
* arguments as far as possible.
|
|
*
|
|
* Whenever a function is eliminated from the expression by means of
|
|
* constant-expression evaluation or inlining, we add the function to
|
|
* root->glob->invalItems. This ensures the plan is known to depend on
|
|
* such functions, even though they aren't referenced anymore.
|
|
*
|
|
* We assume that the tree has already been type-checked and contains
|
|
* only operators and functions that are reasonable to try to execute.
|
|
*
|
|
* NOTE: "root" can be passed as NULL if the caller never wants to do any
|
|
* Param substitutions nor receive info about inlined functions.
|
|
*
|
|
* NOTE: the planner assumes that this will always flatten nested AND and
|
|
* OR clauses into N-argument form. See comments in prepqual.c.
|
|
*
|
|
* NOTE: another critical effect is that any function calls that require
|
|
* default arguments will be expanded, and named-argument calls will be
|
|
* converted to positional notation. The executor won't handle either.
|
|
*--------------------
|
|
*/
|
|
Node *
|
|
eval_const_expressions(PlannerInfo *root, Node *node)
|
|
{
|
|
eval_const_expressions_context context;
|
|
|
|
if (root)
|
|
context.boundParams = root->glob->boundParams; /* bound Params */
|
|
else
|
|
context.boundParams = NULL;
|
|
context.root = root; /* for inlined-function dependencies */
|
|
context.active_fns = NIL; /* nothing being recursively simplified */
|
|
context.case_val = NULL; /* no CASE being examined */
|
|
context.estimate = false; /* safe transformations only */
|
|
return eval_const_expressions_mutator(node, &context);
|
|
}
|
|
|
|
/*--------------------
|
|
* estimate_expression_value
|
|
*
|
|
* This function attempts to estimate the value of an expression for
|
|
* planning purposes. It is in essence a more aggressive version of
|
|
* eval_const_expressions(): we will perform constant reductions that are
|
|
* not necessarily 100% safe, but are reasonable for estimation purposes.
|
|
*
|
|
* Currently the extra steps that are taken in this mode are:
|
|
* 1. Substitute values for Params, where a bound Param value has been made
|
|
* available by the caller of planner(), even if the Param isn't marked
|
|
* constant. This effectively means that we plan using the first supplied
|
|
* value of the Param.
|
|
* 2. Fold stable, as well as immutable, functions to constants.
|
|
* 3. Reduce PlaceHolderVar nodes to their contained expressions.
|
|
*--------------------
|
|
*/
|
|
Node *
|
|
estimate_expression_value(PlannerInfo *root, Node *node)
|
|
{
|
|
eval_const_expressions_context context;
|
|
|
|
context.boundParams = root->glob->boundParams; /* bound Params */
|
|
/* we do not need to mark the plan as depending on inlined functions */
|
|
context.root = NULL;
|
|
context.active_fns = NIL; /* nothing being recursively simplified */
|
|
context.case_val = NULL; /* no CASE being examined */
|
|
context.estimate = true; /* unsafe transformations OK */
|
|
return eval_const_expressions_mutator(node, &context);
|
|
}
|
|
|
|
/*
|
|
* The generic case in eval_const_expressions_mutator is to recurse using
|
|
* expression_tree_mutator, which will copy the given node unchanged but
|
|
* const-simplify its arguments (if any) as far as possible. If the node
|
|
* itself does immutable processing, and each of its arguments were reduced
|
|
* to a Const, we can then reduce it to a Const using evaluate_expr. (Some
|
|
* node types need more complicated logic; for example, a CASE expression
|
|
* might be reducible to a constant even if not all its subtrees are.)
|
|
*/
|
|
#define ece_generic_processing(node) \
|
|
expression_tree_mutator((Node *) (node), eval_const_expressions_mutator, \
|
|
(void *) context)
|
|
|
|
/*
|
|
* Check whether all arguments of the given node were reduced to Consts.
|
|
* By going directly to expression_tree_walker, contain_non_const_walker
|
|
* is not applied to the node itself, only to its children.
|
|
*/
|
|
#define ece_all_arguments_const(node) \
|
|
(!expression_tree_walker((Node *) (node), contain_non_const_walker, NULL))
|
|
|
|
/* Generic macro for applying evaluate_expr */
|
|
#define ece_evaluate_expr(node) \
|
|
((Node *) evaluate_expr((Expr *) (node), \
|
|
exprType((Node *) (node)), \
|
|
exprTypmod((Node *) (node)), \
|
|
exprCollation((Node *) (node))))
|
|
|
|
/*
|
|
* Recursive guts of eval_const_expressions/estimate_expression_value
|
|
*/
|
|
static Node *
|
|
eval_const_expressions_mutator(Node *node,
|
|
eval_const_expressions_context *context)
|
|
{
|
|
if (node == NULL)
|
|
return NULL;
|
|
switch (nodeTag(node))
|
|
{
|
|
case T_Param:
|
|
{
|
|
Param *param = (Param *) node;
|
|
ParamListInfo paramLI = context->boundParams;
|
|
|
|
/* Look to see if we've been given a value for this Param */
|
|
if (param->paramkind == PARAM_EXTERN &&
|
|
paramLI != NULL &&
|
|
param->paramid > 0 &&
|
|
param->paramid <= paramLI->numParams)
|
|
{
|
|
ParamExternData *prm;
|
|
ParamExternData prmdata;
|
|
|
|
/*
|
|
* Give hook a chance in case parameter is dynamic. Tell
|
|
* it that this fetch is speculative, so it should avoid
|
|
* erroring out if parameter is unavailable.
|
|
*/
|
|
if (paramLI->paramFetch != NULL)
|
|
prm = paramLI->paramFetch(paramLI, param->paramid,
|
|
true, &prmdata);
|
|
else
|
|
prm = ¶mLI->params[param->paramid - 1];
|
|
|
|
/*
|
|
* We don't just check OidIsValid, but insist that the
|
|
* fetched type match the Param, just in case the hook did
|
|
* something unexpected. No need to throw an error here
|
|
* though; leave that for runtime.
|
|
*/
|
|
if (OidIsValid(prm->ptype) &&
|
|
prm->ptype == param->paramtype)
|
|
{
|
|
/* OK to substitute parameter value? */
|
|
if (context->estimate ||
|
|
(prm->pflags & PARAM_FLAG_CONST))
|
|
{
|
|
/*
|
|
* Return a Const representing the param value.
|
|
* Must copy pass-by-ref datatypes, since the
|
|
* Param might be in a memory context
|
|
* shorter-lived than our output plan should be.
|
|
*/
|
|
int16 typLen;
|
|
bool typByVal;
|
|
Datum pval;
|
|
|
|
get_typlenbyval(param->paramtype,
|
|
&typLen, &typByVal);
|
|
if (prm->isnull || typByVal)
|
|
pval = prm->value;
|
|
else
|
|
pval = datumCopy(prm->value, typByVal, typLen);
|
|
return (Node *) makeConst(param->paramtype,
|
|
param->paramtypmod,
|
|
param->paramcollid,
|
|
(int) typLen,
|
|
pval,
|
|
prm->isnull,
|
|
typByVal);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Not replaceable, so just copy the Param (no need to
|
|
* recurse)
|
|
*/
|
|
return (Node *) copyObject(param);
|
|
}
|
|
case T_WindowFunc:
|
|
{
|
|
WindowFunc *expr = (WindowFunc *) node;
|
|
Oid funcid = expr->winfnoid;
|
|
List *args;
|
|
Expr *aggfilter;
|
|
HeapTuple func_tuple;
|
|
WindowFunc *newexpr;
|
|
|
|
/*
|
|
* We can't really simplify a WindowFunc node, but we mustn't
|
|
* just fall through to the default processing, because we
|
|
* have to apply expand_function_arguments to its argument
|
|
* list. That takes care of inserting default arguments and
|
|
* expanding named-argument notation.
|
|
*/
|
|
func_tuple = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
|
|
if (!HeapTupleIsValid(func_tuple))
|
|
elog(ERROR, "cache lookup failed for function %u", funcid);
|
|
|
|
args = expand_function_arguments(expr->args, expr->wintype,
|
|
func_tuple);
|
|
|
|
ReleaseSysCache(func_tuple);
|
|
|
|
/* Now, recursively simplify the args (which are a List) */
|
|
args = (List *)
|
|
expression_tree_mutator((Node *) args,
|
|
eval_const_expressions_mutator,
|
|
(void *) context);
|
|
/* ... and the filter expression, which isn't */
|
|
aggfilter = (Expr *)
|
|
eval_const_expressions_mutator((Node *) expr->aggfilter,
|
|
context);
|
|
|
|
/* And build the replacement WindowFunc node */
|
|
newexpr = makeNode(WindowFunc);
|
|
newexpr->winfnoid = expr->winfnoid;
|
|
newexpr->wintype = expr->wintype;
|
|
newexpr->wincollid = expr->wincollid;
|
|
newexpr->inputcollid = expr->inputcollid;
|
|
newexpr->args = args;
|
|
newexpr->aggfilter = aggfilter;
|
|
newexpr->winref = expr->winref;
|
|
newexpr->winstar = expr->winstar;
|
|
newexpr->winagg = expr->winagg;
|
|
newexpr->location = expr->location;
|
|
|
|
return (Node *) newexpr;
|
|
}
|
|
case T_FuncExpr:
|
|
{
|
|
FuncExpr *expr = (FuncExpr *) node;
|
|
List *args = expr->args;
|
|
Expr *simple;
|
|
FuncExpr *newexpr;
|
|
|
|
/*
|
|
* Code for op/func reduction is pretty bulky, so split it out
|
|
* as a separate function. Note: exprTypmod normally returns
|
|
* -1 for a FuncExpr, but not when the node is recognizably a
|
|
* length coercion; we want to preserve the typmod in the
|
|
* eventual Const if so.
|
|
*/
|
|
simple = simplify_function(expr->funcid,
|
|
expr->funcresulttype,
|
|
exprTypmod(node),
|
|
expr->funccollid,
|
|
expr->inputcollid,
|
|
&args,
|
|
expr->funcvariadic,
|
|
true,
|
|
true,
|
|
context);
|
|
if (simple) /* successfully simplified it */
|
|
return (Node *) simple;
|
|
|
|
/*
|
|
* The expression cannot be simplified any further, so build
|
|
* and return a replacement FuncExpr node using the
|
|
* possibly-simplified arguments. Note that we have also
|
|
* converted the argument list to positional notation.
|
|
*/
|
|
newexpr = makeNode(FuncExpr);
|
|
newexpr->funcid = expr->funcid;
|
|
newexpr->funcresulttype = expr->funcresulttype;
|
|
newexpr->funcretset = expr->funcretset;
|
|
newexpr->funcvariadic = expr->funcvariadic;
|
|
newexpr->funcformat = expr->funcformat;
|
|
newexpr->funccollid = expr->funccollid;
|
|
newexpr->inputcollid = expr->inputcollid;
|
|
newexpr->args = args;
|
|
newexpr->location = expr->location;
|
|
return (Node *) newexpr;
|
|
}
|
|
case T_OpExpr:
|
|
{
|
|
OpExpr *expr = (OpExpr *) node;
|
|
List *args = expr->args;
|
|
Expr *simple;
|
|
OpExpr *newexpr;
|
|
|
|
/*
|
|
* Need to get OID of underlying function. Okay to scribble
|
|
* on input to this extent.
|
|
*/
|
|
set_opfuncid(expr);
|
|
|
|
/*
|
|
* Code for op/func reduction is pretty bulky, so split it out
|
|
* as a separate function.
|
|
*/
|
|
simple = simplify_function(expr->opfuncid,
|
|
expr->opresulttype, -1,
|
|
expr->opcollid,
|
|
expr->inputcollid,
|
|
&args,
|
|
false,
|
|
true,
|
|
true,
|
|
context);
|
|
if (simple) /* successfully simplified it */
|
|
return (Node *) simple;
|
|
|
|
/*
|
|
* If the operator is boolean equality or inequality, we know
|
|
* how to simplify cases involving one constant and one
|
|
* non-constant argument.
|
|
*/
|
|
if (expr->opno == BooleanEqualOperator ||
|
|
expr->opno == BooleanNotEqualOperator)
|
|
{
|
|
simple = (Expr *) simplify_boolean_equality(expr->opno,
|
|
args);
|
|
if (simple) /* successfully simplified it */
|
|
return (Node *) simple;
|
|
}
|
|
|
|
/*
|
|
* The expression cannot be simplified any further, so build
|
|
* and return a replacement OpExpr node using the
|
|
* possibly-simplified arguments.
|
|
*/
|
|
newexpr = makeNode(OpExpr);
|
|
newexpr->opno = expr->opno;
|
|
newexpr->opfuncid = expr->opfuncid;
|
|
newexpr->opresulttype = expr->opresulttype;
|
|
newexpr->opretset = expr->opretset;
|
|
newexpr->opcollid = expr->opcollid;
|
|
newexpr->inputcollid = expr->inputcollid;
|
|
newexpr->args = args;
|
|
newexpr->location = expr->location;
|
|
return (Node *) newexpr;
|
|
}
|
|
case T_DistinctExpr:
|
|
{
|
|
DistinctExpr *expr = (DistinctExpr *) node;
|
|
List *args;
|
|
ListCell *arg;
|
|
bool has_null_input = false;
|
|
bool all_null_input = true;
|
|
bool has_nonconst_input = false;
|
|
Expr *simple;
|
|
DistinctExpr *newexpr;
|
|
|
|
/*
|
|
* Reduce constants in the DistinctExpr's arguments. We know
|
|
* args is either NIL or a List node, so we can call
|
|
* expression_tree_mutator directly rather than recursing to
|
|
* self.
|
|
*/
|
|
args = (List *) expression_tree_mutator((Node *) expr->args,
|
|
eval_const_expressions_mutator,
|
|
(void *) context);
|
|
|
|
/*
|
|
* We must do our own check for NULLs because DistinctExpr has
|
|
* different results for NULL input than the underlying
|
|
* operator does.
|
|
*/
|
|
foreach(arg, args)
|
|
{
|
|
if (IsA(lfirst(arg), Const))
|
|
{
|
|
has_null_input |= ((Const *) lfirst(arg))->constisnull;
|
|
all_null_input &= ((Const *) lfirst(arg))->constisnull;
|
|
}
|
|
else
|
|
has_nonconst_input = true;
|
|
}
|
|
|
|
/* all constants? then can optimize this out */
|
|
if (!has_nonconst_input)
|
|
{
|
|
/* all nulls? then not distinct */
|
|
if (all_null_input)
|
|
return makeBoolConst(false, false);
|
|
|
|
/* one null? then distinct */
|
|
if (has_null_input)
|
|
return makeBoolConst(true, false);
|
|
|
|
/* otherwise try to evaluate the '=' operator */
|
|
/* (NOT okay to try to inline it, though!) */
|
|
|
|
/*
|
|
* Need to get OID of underlying function. Okay to
|
|
* scribble on input to this extent.
|
|
*/
|
|
set_opfuncid((OpExpr *) expr); /* rely on struct
|
|
* equivalence */
|
|
|
|
/*
|
|
* Code for op/func reduction is pretty bulky, so split it
|
|
* out as a separate function.
|
|
*/
|
|
simple = simplify_function(expr->opfuncid,
|
|
expr->opresulttype, -1,
|
|
expr->opcollid,
|
|
expr->inputcollid,
|
|
&args,
|
|
false,
|
|
false,
|
|
false,
|
|
context);
|
|
if (simple) /* successfully simplified it */
|
|
{
|
|
/*
|
|
* Since the underlying operator is "=", must negate
|
|
* its result
|
|
*/
|
|
Const *csimple = castNode(Const, simple);
|
|
|
|
csimple->constvalue =
|
|
BoolGetDatum(!DatumGetBool(csimple->constvalue));
|
|
return (Node *) csimple;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* The expression cannot be simplified any further, so build
|
|
* and return a replacement DistinctExpr node using the
|
|
* possibly-simplified arguments.
|
|
*/
|
|
newexpr = makeNode(DistinctExpr);
|
|
newexpr->opno = expr->opno;
|
|
newexpr->opfuncid = expr->opfuncid;
|
|
newexpr->opresulttype = expr->opresulttype;
|
|
newexpr->opretset = expr->opretset;
|
|
newexpr->opcollid = expr->opcollid;
|
|
newexpr->inputcollid = expr->inputcollid;
|
|
newexpr->args = args;
|
|
newexpr->location = expr->location;
|
|
return (Node *) newexpr;
|
|
}
|
|
case T_ScalarArrayOpExpr:
|
|
{
|
|
ScalarArrayOpExpr *saop;
|
|
|
|
/* Copy the node and const-simplify its arguments */
|
|
saop = (ScalarArrayOpExpr *) ece_generic_processing(node);
|
|
|
|
/* Make sure we know underlying function */
|
|
set_sa_opfuncid(saop);
|
|
|
|
/*
|
|
* If all arguments are Consts, and it's a safe function, we
|
|
* can fold to a constant
|
|
*/
|
|
if (ece_all_arguments_const(saop) &&
|
|
ece_function_is_safe(saop->opfuncid, context))
|
|
return ece_evaluate_expr(saop);
|
|
return (Node *) saop;
|
|
}
|
|
case T_BoolExpr:
|
|
{
|
|
BoolExpr *expr = (BoolExpr *) node;
|
|
|
|
switch (expr->boolop)
|
|
{
|
|
case OR_EXPR:
|
|
{
|
|
List *newargs;
|
|
bool haveNull = false;
|
|
bool forceTrue = false;
|
|
|
|
newargs = simplify_or_arguments(expr->args,
|
|
context,
|
|
&haveNull,
|
|
&forceTrue);
|
|
if (forceTrue)
|
|
return makeBoolConst(true, false);
|
|
if (haveNull)
|
|
newargs = lappend(newargs,
|
|
makeBoolConst(false, true));
|
|
/* If all the inputs are FALSE, result is FALSE */
|
|
if (newargs == NIL)
|
|
return makeBoolConst(false, false);
|
|
|
|
/*
|
|
* If only one nonconst-or-NULL input, it's the
|
|
* result
|
|
*/
|
|
if (list_length(newargs) == 1)
|
|
return (Node *) linitial(newargs);
|
|
/* Else we still need an OR node */
|
|
return (Node *) make_orclause(newargs);
|
|
}
|
|
case AND_EXPR:
|
|
{
|
|
List *newargs;
|
|
bool haveNull = false;
|
|
bool forceFalse = false;
|
|
|
|
newargs = simplify_and_arguments(expr->args,
|
|
context,
|
|
&haveNull,
|
|
&forceFalse);
|
|
if (forceFalse)
|
|
return makeBoolConst(false, false);
|
|
if (haveNull)
|
|
newargs = lappend(newargs,
|
|
makeBoolConst(false, true));
|
|
/* If all the inputs are TRUE, result is TRUE */
|
|
if (newargs == NIL)
|
|
return makeBoolConst(true, false);
|
|
|
|
/*
|
|
* If only one nonconst-or-NULL input, it's the
|
|
* result
|
|
*/
|
|
if (list_length(newargs) == 1)
|
|
return (Node *) linitial(newargs);
|
|
/* Else we still need an AND node */
|
|
return (Node *) make_andclause(newargs);
|
|
}
|
|
case NOT_EXPR:
|
|
{
|
|
Node *arg;
|
|
|
|
Assert(list_length(expr->args) == 1);
|
|
arg = eval_const_expressions_mutator(linitial(expr->args),
|
|
context);
|
|
|
|
/*
|
|
* Use negate_clause() to see if we can simplify
|
|
* away the NOT.
|
|
*/
|
|
return negate_clause(arg);
|
|
}
|
|
default:
|
|
elog(ERROR, "unrecognized boolop: %d",
|
|
(int) expr->boolop);
|
|
break;
|
|
}
|
|
break;
|
|
}
|
|
case T_SubPlan:
|
|
case T_AlternativeSubPlan:
|
|
|
|
/*
|
|
* Return a SubPlan unchanged --- too late to do anything with it.
|
|
*
|
|
* XXX should we ereport() here instead? Probably this routine
|
|
* should never be invoked after SubPlan creation.
|
|
*/
|
|
return node;
|
|
case T_RelabelType:
|
|
{
|
|
RelabelType *relabel = (RelabelType *) node;
|
|
Node *arg;
|
|
|
|
/* Simplify the input ... */
|
|
arg = eval_const_expressions_mutator((Node *) relabel->arg,
|
|
context);
|
|
/* ... and attach a new RelabelType node, if needed */
|
|
return apply_const_relabel(arg,
|
|
relabel->resulttype,
|
|
relabel->resulttypmod,
|
|
relabel->resultcollid,
|
|
relabel->relabelformat,
|
|
relabel->location);
|
|
}
|
|
case T_CoerceViaIO:
|
|
{
|
|
CoerceViaIO *expr = (CoerceViaIO *) node;
|
|
List *args;
|
|
Oid outfunc;
|
|
bool outtypisvarlena;
|
|
Oid infunc;
|
|
Oid intypioparam;
|
|
Expr *simple;
|
|
CoerceViaIO *newexpr;
|
|
|
|
/* Make a List so we can use simplify_function */
|
|
args = list_make1(expr->arg);
|
|
|
|
/*
|
|
* CoerceViaIO represents calling the source type's output
|
|
* function then the result type's input function. So, try to
|
|
* simplify it as though it were a stack of two such function
|
|
* calls. First we need to know what the functions are.
|
|
*
|
|
* Note that the coercion functions are assumed not to care
|
|
* about input collation, so we just pass InvalidOid for that.
|
|
*/
|
|
getTypeOutputInfo(exprType((Node *) expr->arg),
|
|
&outfunc, &outtypisvarlena);
|
|
getTypeInputInfo(expr->resulttype,
|
|
&infunc, &intypioparam);
|
|
|
|
simple = simplify_function(outfunc,
|
|
CSTRINGOID, -1,
|
|
InvalidOid,
|
|
InvalidOid,
|
|
&args,
|
|
false,
|
|
true,
|
|
true,
|
|
context);
|
|
if (simple) /* successfully simplified output fn */
|
|
{
|
|
/*
|
|
* Input functions may want 1 to 3 arguments. We always
|
|
* supply all three, trusting that nothing downstream will
|
|
* complain.
|
|
*/
|
|
args = list_make3(simple,
|
|
makeConst(OIDOID,
|
|
-1,
|
|
InvalidOid,
|
|
sizeof(Oid),
|
|
ObjectIdGetDatum(intypioparam),
|
|
false,
|
|
true),
|
|
makeConst(INT4OID,
|
|
-1,
|
|
InvalidOid,
|
|
sizeof(int32),
|
|
Int32GetDatum(-1),
|
|
false,
|
|
true));
|
|
|
|
simple = simplify_function(infunc,
|
|
expr->resulttype, -1,
|
|
expr->resultcollid,
|
|
InvalidOid,
|
|
&args,
|
|
false,
|
|
false,
|
|
true,
|
|
context);
|
|
if (simple) /* successfully simplified input fn */
|
|
return (Node *) simple;
|
|
}
|
|
|
|
/*
|
|
* The expression cannot be simplified any further, so build
|
|
* and return a replacement CoerceViaIO node using the
|
|
* possibly-simplified argument.
|
|
*/
|
|
newexpr = makeNode(CoerceViaIO);
|
|
newexpr->arg = (Expr *) linitial(args);
|
|
newexpr->resulttype = expr->resulttype;
|
|
newexpr->resultcollid = expr->resultcollid;
|
|
newexpr->coerceformat = expr->coerceformat;
|
|
newexpr->location = expr->location;
|
|
return (Node *) newexpr;
|
|
}
|
|
case T_ArrayCoerceExpr:
|
|
{
|
|
ArrayCoerceExpr *ac = makeNode(ArrayCoerceExpr);
|
|
Node *save_case_val;
|
|
|
|
/*
|
|
* Copy the node and const-simplify its arguments. We can't
|
|
* use ece_generic_processing() here because we need to mess
|
|
* with case_val only while processing the elemexpr.
|
|
*/
|
|
memcpy(ac, node, sizeof(ArrayCoerceExpr));
|
|
ac->arg = (Expr *)
|
|
eval_const_expressions_mutator((Node *) ac->arg,
|
|
context);
|
|
|
|
/*
|
|
* Set up for the CaseTestExpr node contained in the elemexpr.
|
|
* We must prevent it from absorbing any outer CASE value.
|
|
*/
|
|
save_case_val = context->case_val;
|
|
context->case_val = NULL;
|
|
|
|
ac->elemexpr = (Expr *)
|
|
eval_const_expressions_mutator((Node *) ac->elemexpr,
|
|
context);
|
|
|
|
context->case_val = save_case_val;
|
|
|
|
/*
|
|
* If constant argument and the per-element expression is
|
|
* immutable, we can simplify the whole thing to a constant.
|
|
* Exception: although contain_mutable_functions considers
|
|
* CoerceToDomain immutable for historical reasons, let's not
|
|
* do so here; this ensures coercion to an array-over-domain
|
|
* does not apply the domain's constraints until runtime.
|
|
*/
|
|
if (ac->arg && IsA(ac->arg, Const) &&
|
|
ac->elemexpr && !IsA(ac->elemexpr, CoerceToDomain) &&
|
|
!contain_mutable_functions((Node *) ac->elemexpr))
|
|
return ece_evaluate_expr(ac);
|
|
|
|
return (Node *) ac;
|
|
}
|
|
case T_CollateExpr:
|
|
{
|
|
/*
|
|
* We replace CollateExpr with RelabelType, so as to improve
|
|
* uniformity of expression representation and thus simplify
|
|
* comparison of expressions. Hence this looks very nearly
|
|
* the same as the RelabelType case, and we can apply the same
|
|
* optimizations to avoid unnecessary RelabelTypes.
|
|
*/
|
|
CollateExpr *collate = (CollateExpr *) node;
|
|
Node *arg;
|
|
|
|
/* Simplify the input ... */
|
|
arg = eval_const_expressions_mutator((Node *) collate->arg,
|
|
context);
|
|
/* ... and attach a new RelabelType node, if needed */
|
|
return apply_const_relabel(arg,
|
|
exprType(arg),
|
|
exprTypmod(arg),
|
|
collate->collOid,
|
|
COERCE_IMPLICIT_CAST,
|
|
collate->location);
|
|
}
|
|
case T_CaseExpr:
|
|
{
|
|
/*----------
|
|
* CASE expressions can be simplified if there are constant
|
|
* condition clauses:
|
|
* FALSE (or NULL): drop the alternative
|
|
* TRUE: drop all remaining alternatives
|
|
* If the first non-FALSE alternative is a constant TRUE,
|
|
* we can simplify the entire CASE to that alternative's
|
|
* expression. If there are no non-FALSE alternatives,
|
|
* we simplify the entire CASE to the default result (ELSE).
|
|
*
|
|
* If we have a simple-form CASE with constant test
|
|
* expression, we substitute the constant value for contained
|
|
* CaseTestExpr placeholder nodes, so that we have the
|
|
* opportunity to reduce constant test conditions. For
|
|
* example this allows
|
|
* CASE 0 WHEN 0 THEN 1 ELSE 1/0 END
|
|
* to reduce to 1 rather than drawing a divide-by-0 error.
|
|
* Note that when the test expression is constant, we don't
|
|
* have to include it in the resulting CASE; for example
|
|
* CASE 0 WHEN x THEN y ELSE z END
|
|
* is transformed by the parser to
|
|
* CASE 0 WHEN CaseTestExpr = x THEN y ELSE z END
|
|
* which we can simplify to
|
|
* CASE WHEN 0 = x THEN y ELSE z END
|
|
* It is not necessary for the executor to evaluate the "arg"
|
|
* expression when executing the CASE, since any contained
|
|
* CaseTestExprs that might have referred to it will have been
|
|
* replaced by the constant.
|
|
*----------
|
|
*/
|
|
CaseExpr *caseexpr = (CaseExpr *) node;
|
|
CaseExpr *newcase;
|
|
Node *save_case_val;
|
|
Node *newarg;
|
|
List *newargs;
|
|
bool const_true_cond;
|
|
Node *defresult = NULL;
|
|
ListCell *arg;
|
|
|
|
/* Simplify the test expression, if any */
|
|
newarg = eval_const_expressions_mutator((Node *) caseexpr->arg,
|
|
context);
|
|
|
|
/* Set up for contained CaseTestExpr nodes */
|
|
save_case_val = context->case_val;
|
|
if (newarg && IsA(newarg, Const))
|
|
{
|
|
context->case_val = newarg;
|
|
newarg = NULL; /* not needed anymore, see above */
|
|
}
|
|
else
|
|
context->case_val = NULL;
|
|
|
|
/* Simplify the WHEN clauses */
|
|
newargs = NIL;
|
|
const_true_cond = false;
|
|
foreach(arg, caseexpr->args)
|
|
{
|
|
CaseWhen *oldcasewhen = lfirst_node(CaseWhen, arg);
|
|
Node *casecond;
|
|
Node *caseresult;
|
|
|
|
/* Simplify this alternative's test condition */
|
|
casecond = eval_const_expressions_mutator((Node *) oldcasewhen->expr,
|
|
context);
|
|
|
|
/*
|
|
* If the test condition is constant FALSE (or NULL), then
|
|
* drop this WHEN clause completely, without processing
|
|
* the result.
|
|
*/
|
|
if (casecond && IsA(casecond, Const))
|
|
{
|
|
Const *const_input = (Const *) casecond;
|
|
|
|
if (const_input->constisnull ||
|
|
!DatumGetBool(const_input->constvalue))
|
|
continue; /* drop alternative with FALSE cond */
|
|
/* Else it's constant TRUE */
|
|
const_true_cond = true;
|
|
}
|
|
|
|
/* Simplify this alternative's result value */
|
|
caseresult = eval_const_expressions_mutator((Node *) oldcasewhen->result,
|
|
context);
|
|
|
|
/* If non-constant test condition, emit a new WHEN node */
|
|
if (!const_true_cond)
|
|
{
|
|
CaseWhen *newcasewhen = makeNode(CaseWhen);
|
|
|
|
newcasewhen->expr = (Expr *) casecond;
|
|
newcasewhen->result = (Expr *) caseresult;
|
|
newcasewhen->location = oldcasewhen->location;
|
|
newargs = lappend(newargs, newcasewhen);
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* Found a TRUE condition, so none of the remaining
|
|
* alternatives can be reached. We treat the result as
|
|
* the default result.
|
|
*/
|
|
defresult = caseresult;
|
|
break;
|
|
}
|
|
|
|
/* Simplify the default result, unless we replaced it above */
|
|
if (!const_true_cond)
|
|
defresult = eval_const_expressions_mutator((Node *) caseexpr->defresult,
|
|
context);
|
|
|
|
context->case_val = save_case_val;
|
|
|
|
/*
|
|
* If no non-FALSE alternatives, CASE reduces to the default
|
|
* result
|
|
*/
|
|
if (newargs == NIL)
|
|
return defresult;
|
|
/* Otherwise we need a new CASE node */
|
|
newcase = makeNode(CaseExpr);
|
|
newcase->casetype = caseexpr->casetype;
|
|
newcase->casecollid = caseexpr->casecollid;
|
|
newcase->arg = (Expr *) newarg;
|
|
newcase->args = newargs;
|
|
newcase->defresult = (Expr *) defresult;
|
|
newcase->location = caseexpr->location;
|
|
return (Node *) newcase;
|
|
}
|
|
case T_CaseTestExpr:
|
|
{
|
|
/*
|
|
* If we know a constant test value for the current CASE
|
|
* construct, substitute it for the placeholder. Else just
|
|
* return the placeholder as-is.
|
|
*/
|
|
if (context->case_val)
|
|
return copyObject(context->case_val);
|
|
else
|
|
return copyObject(node);
|
|
}
|
|
case T_SubscriptingRef:
|
|
case T_ArrayExpr:
|
|
case T_RowExpr:
|
|
case T_MinMaxExpr:
|
|
{
|
|
/*
|
|
* Generic handling for node types whose own processing is
|
|
* known to be immutable, and for which we need no smarts
|
|
* beyond "simplify if all inputs are constants".
|
|
*
|
|
* Treating MinMaxExpr this way amounts to assuming that the
|
|
* btree comparison function it calls is immutable; see the
|
|
* reasoning in contain_mutable_functions_walker.
|
|
*/
|
|
|
|
/* Copy the node and const-simplify its arguments */
|
|
node = ece_generic_processing(node);
|
|
/* If all arguments are Consts, we can fold to a constant */
|
|
if (ece_all_arguments_const(node))
|
|
return ece_evaluate_expr(node);
|
|
return node;
|
|
}
|
|
case T_CoalesceExpr:
|
|
{
|
|
CoalesceExpr *coalesceexpr = (CoalesceExpr *) node;
|
|
CoalesceExpr *newcoalesce;
|
|
List *newargs;
|
|
ListCell *arg;
|
|
|
|
newargs = NIL;
|
|
foreach(arg, coalesceexpr->args)
|
|
{
|
|
Node *e;
|
|
|
|
e = eval_const_expressions_mutator((Node *) lfirst(arg),
|
|
context);
|
|
|
|
/*
|
|
* We can remove null constants from the list. For a
|
|
* non-null constant, if it has not been preceded by any
|
|
* other non-null-constant expressions then it is the
|
|
* result. Otherwise, it's the next argument, but we can
|
|
* drop following arguments since they will never be
|
|
* reached.
|
|
*/
|
|
if (IsA(e, Const))
|
|
{
|
|
if (((Const *) e)->constisnull)
|
|
continue; /* drop null constant */
|
|
if (newargs == NIL)
|
|
return e; /* first expr */
|
|
newargs = lappend(newargs, e);
|
|
break;
|
|
}
|
|
newargs = lappend(newargs, e);
|
|
}
|
|
|
|
/*
|
|
* If all the arguments were constant null, the result is just
|
|
* null
|
|
*/
|
|
if (newargs == NIL)
|
|
return (Node *) makeNullConst(coalesceexpr->coalescetype,
|
|
-1,
|
|
coalesceexpr->coalescecollid);
|
|
|
|
newcoalesce = makeNode(CoalesceExpr);
|
|
newcoalesce->coalescetype = coalesceexpr->coalescetype;
|
|
newcoalesce->coalescecollid = coalesceexpr->coalescecollid;
|
|
newcoalesce->args = newargs;
|
|
newcoalesce->location = coalesceexpr->location;
|
|
return (Node *) newcoalesce;
|
|
}
|
|
case T_SQLValueFunction:
|
|
{
|
|
/*
|
|
* All variants of SQLValueFunction are stable, so if we are
|
|
* estimating the expression's value, we should evaluate the
|
|
* current function value. Otherwise just copy.
|
|
*/
|
|
SQLValueFunction *svf = (SQLValueFunction *) node;
|
|
|
|
if (context->estimate)
|
|
return (Node *) evaluate_expr((Expr *) svf,
|
|
svf->type,
|
|
svf->typmod,
|
|
InvalidOid);
|
|
else
|
|
return copyObject((Node *) svf);
|
|
}
|
|
case T_FieldSelect:
|
|
{
|
|
/*
|
|
* We can optimize field selection from a whole-row Var into a
|
|
* simple Var. (This case won't be generated directly by the
|
|
* parser, because ParseComplexProjection short-circuits it.
|
|
* But it can arise while simplifying functions.) Also, we
|
|
* can optimize field selection from a RowExpr construct, or
|
|
* of course from a constant.
|
|
*
|
|
* However, replacing a whole-row Var in this way has a
|
|
* pitfall: if we've already built the rel targetlist for the
|
|
* source relation, then the whole-row Var is scheduled to be
|
|
* produced by the relation scan, but the simple Var probably
|
|
* isn't, which will lead to a failure in setrefs.c. This is
|
|
* not a problem when handling simple single-level queries, in
|
|
* which expression simplification always happens first. It
|
|
* is a risk for lateral references from subqueries, though.
|
|
* To avoid such failures, don't optimize uplevel references.
|
|
*
|
|
* We must also check that the declared type of the field is
|
|
* still the same as when the FieldSelect was created --- this
|
|
* can change if someone did ALTER COLUMN TYPE on the rowtype.
|
|
* If it isn't, we skip the optimization; the case will
|
|
* probably fail at runtime, but that's not our problem here.
|
|
*/
|
|
FieldSelect *fselect = (FieldSelect *) node;
|
|
FieldSelect *newfselect;
|
|
Node *arg;
|
|
|
|
arg = eval_const_expressions_mutator((Node *) fselect->arg,
|
|
context);
|
|
if (arg && IsA(arg, Var) &&
|
|
((Var *) arg)->varattno == InvalidAttrNumber &&
|
|
((Var *) arg)->varlevelsup == 0)
|
|
{
|
|
if (rowtype_field_matches(((Var *) arg)->vartype,
|
|
fselect->fieldnum,
|
|
fselect->resulttype,
|
|
fselect->resulttypmod,
|
|
fselect->resultcollid))
|
|
return (Node *) makeVar(((Var *) arg)->varno,
|
|
fselect->fieldnum,
|
|
fselect->resulttype,
|
|
fselect->resulttypmod,
|
|
fselect->resultcollid,
|
|
((Var *) arg)->varlevelsup);
|
|
}
|
|
if (arg && IsA(arg, RowExpr))
|
|
{
|
|
RowExpr *rowexpr = (RowExpr *) arg;
|
|
|
|
if (fselect->fieldnum > 0 &&
|
|
fselect->fieldnum <= list_length(rowexpr->args))
|
|
{
|
|
Node *fld = (Node *) list_nth(rowexpr->args,
|
|
fselect->fieldnum - 1);
|
|
|
|
if (rowtype_field_matches(rowexpr->row_typeid,
|
|
fselect->fieldnum,
|
|
fselect->resulttype,
|
|
fselect->resulttypmod,
|
|
fselect->resultcollid) &&
|
|
fselect->resulttype == exprType(fld) &&
|
|
fselect->resulttypmod == exprTypmod(fld) &&
|
|
fselect->resultcollid == exprCollation(fld))
|
|
return fld;
|
|
}
|
|
}
|
|
newfselect = makeNode(FieldSelect);
|
|
newfselect->arg = (Expr *) arg;
|
|
newfselect->fieldnum = fselect->fieldnum;
|
|
newfselect->resulttype = fselect->resulttype;
|
|
newfselect->resulttypmod = fselect->resulttypmod;
|
|
newfselect->resultcollid = fselect->resultcollid;
|
|
if (arg && IsA(arg, Const))
|
|
{
|
|
Const *con = (Const *) arg;
|
|
|
|
if (rowtype_field_matches(con->consttype,
|
|
newfselect->fieldnum,
|
|
newfselect->resulttype,
|
|
newfselect->resulttypmod,
|
|
newfselect->resultcollid))
|
|
return ece_evaluate_expr(newfselect);
|
|
}
|
|
return (Node *) newfselect;
|
|
}
|
|
case T_NullTest:
|
|
{
|
|
NullTest *ntest = (NullTest *) node;
|
|
NullTest *newntest;
|
|
Node *arg;
|
|
|
|
arg = eval_const_expressions_mutator((Node *) ntest->arg,
|
|
context);
|
|
if (ntest->argisrow && arg && IsA(arg, RowExpr))
|
|
{
|
|
/*
|
|
* We break ROW(...) IS [NOT] NULL into separate tests on
|
|
* its component fields. This form is usually more
|
|
* efficient to evaluate, as well as being more amenable
|
|
* to optimization.
|
|
*/
|
|
RowExpr *rarg = (RowExpr *) arg;
|
|
List *newargs = NIL;
|
|
ListCell *l;
|
|
|
|
foreach(l, rarg->args)
|
|
{
|
|
Node *relem = (Node *) lfirst(l);
|
|
|
|
/*
|
|
* A constant field refutes the whole NullTest if it's
|
|
* of the wrong nullness; else we can discard it.
|
|
*/
|
|
if (relem && IsA(relem, Const))
|
|
{
|
|
Const *carg = (Const *) relem;
|
|
|
|
if (carg->constisnull ?
|
|
(ntest->nulltesttype == IS_NOT_NULL) :
|
|
(ntest->nulltesttype == IS_NULL))
|
|
return makeBoolConst(false, false);
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* Else, make a scalar (argisrow == false) NullTest
|
|
* for this field. Scalar semantics are required
|
|
* because IS [NOT] NULL doesn't recurse; see comments
|
|
* in ExecEvalRowNullInt().
|
|
*/
|
|
newntest = makeNode(NullTest);
|
|
newntest->arg = (Expr *) relem;
|
|
newntest->nulltesttype = ntest->nulltesttype;
|
|
newntest->argisrow = false;
|
|
newntest->location = ntest->location;
|
|
newargs = lappend(newargs, newntest);
|
|
}
|
|
/* If all the inputs were constants, result is TRUE */
|
|
if (newargs == NIL)
|
|
return makeBoolConst(true, false);
|
|
/* If only one nonconst input, it's the result */
|
|
if (list_length(newargs) == 1)
|
|
return (Node *) linitial(newargs);
|
|
/* Else we need an AND node */
|
|
return (Node *) make_andclause(newargs);
|
|
}
|
|
if (!ntest->argisrow && arg && IsA(arg, Const))
|
|
{
|
|
Const *carg = (Const *) arg;
|
|
bool result;
|
|
|
|
switch (ntest->nulltesttype)
|
|
{
|
|
case IS_NULL:
|
|
result = carg->constisnull;
|
|
break;
|
|
case IS_NOT_NULL:
|
|
result = !carg->constisnull;
|
|
break;
|
|
default:
|
|
elog(ERROR, "unrecognized nulltesttype: %d",
|
|
(int) ntest->nulltesttype);
|
|
result = false; /* keep compiler quiet */
|
|
break;
|
|
}
|
|
|
|
return makeBoolConst(result, false);
|
|
}
|
|
|
|
newntest = makeNode(NullTest);
|
|
newntest->arg = (Expr *) arg;
|
|
newntest->nulltesttype = ntest->nulltesttype;
|
|
newntest->argisrow = ntest->argisrow;
|
|
newntest->location = ntest->location;
|
|
return (Node *) newntest;
|
|
}
|
|
case T_BooleanTest:
|
|
{
|
|
/*
|
|
* This case could be folded into the generic handling used
|
|
* for SubscriptingRef etc. But because the simplification
|
|
* logic is so trivial, applying evaluate_expr() to perform it
|
|
* would be a heavy overhead. BooleanTest is probably common
|
|
* enough to justify keeping this bespoke implementation.
|
|
*/
|
|
BooleanTest *btest = (BooleanTest *) node;
|
|
BooleanTest *newbtest;
|
|
Node *arg;
|
|
|
|
arg = eval_const_expressions_mutator((Node *) btest->arg,
|
|
context);
|
|
if (arg && IsA(arg, Const))
|
|
{
|
|
Const *carg = (Const *) arg;
|
|
bool result;
|
|
|
|
switch (btest->booltesttype)
|
|
{
|
|
case IS_TRUE:
|
|
result = (!carg->constisnull &&
|
|
DatumGetBool(carg->constvalue));
|
|
break;
|
|
case IS_NOT_TRUE:
|
|
result = (carg->constisnull ||
|
|
!DatumGetBool(carg->constvalue));
|
|
break;
|
|
case IS_FALSE:
|
|
result = (!carg->constisnull &&
|
|
!DatumGetBool(carg->constvalue));
|
|
break;
|
|
case IS_NOT_FALSE:
|
|
result = (carg->constisnull ||
|
|
DatumGetBool(carg->constvalue));
|
|
break;
|
|
case IS_UNKNOWN:
|
|
result = carg->constisnull;
|
|
break;
|
|
case IS_NOT_UNKNOWN:
|
|
result = !carg->constisnull;
|
|
break;
|
|
default:
|
|
elog(ERROR, "unrecognized booltesttype: %d",
|
|
(int) btest->booltesttype);
|
|
result = false; /* keep compiler quiet */
|
|
break;
|
|
}
|
|
|
|
return makeBoolConst(result, false);
|
|
}
|
|
|
|
newbtest = makeNode(BooleanTest);
|
|
newbtest->arg = (Expr *) arg;
|
|
newbtest->booltesttype = btest->booltesttype;
|
|
newbtest->location = btest->location;
|
|
return (Node *) newbtest;
|
|
}
|
|
case T_CoerceToDomain:
|
|
{
|
|
/*
|
|
* If the domain currently has no constraints, we replace the
|
|
* CoerceToDomain node with a simple RelabelType, which is
|
|
* both far faster to execute and more amenable to later
|
|
* optimization. We must then mark the plan as needing to be
|
|
* rebuilt if the domain's constraints change.
|
|
*
|
|
* Also, in estimation mode, always replace CoerceToDomain
|
|
* nodes, effectively assuming that the coercion will succeed.
|
|
*/
|
|
CoerceToDomain *cdomain = (CoerceToDomain *) node;
|
|
CoerceToDomain *newcdomain;
|
|
Node *arg;
|
|
|
|
arg = eval_const_expressions_mutator((Node *) cdomain->arg,
|
|
context);
|
|
if (context->estimate ||
|
|
!DomainHasConstraints(cdomain->resulttype))
|
|
{
|
|
/* Record dependency, if this isn't estimation mode */
|
|
if (context->root && !context->estimate)
|
|
record_plan_type_dependency(context->root,
|
|
cdomain->resulttype);
|
|
|
|
/* Generate RelabelType to substitute for CoerceToDomain */
|
|
return apply_const_relabel(arg,
|
|
cdomain->resulttype,
|
|
cdomain->resulttypmod,
|
|
cdomain->resultcollid,
|
|
cdomain->coercionformat,
|
|
cdomain->location);
|
|
}
|
|
|
|
newcdomain = makeNode(CoerceToDomain);
|
|
newcdomain->arg = (Expr *) arg;
|
|
newcdomain->resulttype = cdomain->resulttype;
|
|
newcdomain->resulttypmod = cdomain->resulttypmod;
|
|
newcdomain->resultcollid = cdomain->resultcollid;
|
|
newcdomain->coercionformat = cdomain->coercionformat;
|
|
newcdomain->location = cdomain->location;
|
|
return (Node *) newcdomain;
|
|
}
|
|
case T_PlaceHolderVar:
|
|
|
|
/*
|
|
* In estimation mode, just strip the PlaceHolderVar node
|
|
* altogether; this amounts to estimating that the contained value
|
|
* won't be forced to null by an outer join. In regular mode we
|
|
* just use the default behavior (ie, simplify the expression but
|
|
* leave the PlaceHolderVar node intact).
|
|
*/
|
|
if (context->estimate)
|
|
{
|
|
PlaceHolderVar *phv = (PlaceHolderVar *) node;
|
|
|
|
return eval_const_expressions_mutator((Node *) phv->phexpr,
|
|
context);
|
|
}
|
|
break;
|
|
case T_ConvertRowtypeExpr:
|
|
{
|
|
ConvertRowtypeExpr *cre = castNode(ConvertRowtypeExpr, node);
|
|
Node *arg;
|
|
ConvertRowtypeExpr *newcre;
|
|
|
|
arg = eval_const_expressions_mutator((Node *) cre->arg,
|
|
context);
|
|
|
|
newcre = makeNode(ConvertRowtypeExpr);
|
|
newcre->resulttype = cre->resulttype;
|
|
newcre->convertformat = cre->convertformat;
|
|
newcre->location = cre->location;
|
|
|
|
/*
|
|
* In case of a nested ConvertRowtypeExpr, we can convert the
|
|
* leaf row directly to the topmost row format without any
|
|
* intermediate conversions. (This works because
|
|
* ConvertRowtypeExpr is used only for child->parent
|
|
* conversion in inheritance trees, which works by exact match
|
|
* of column name, and a column absent in an intermediate
|
|
* result can't be present in the final result.)
|
|
*
|
|
* No need to check more than one level deep, because the
|
|
* above recursion will have flattened anything else.
|
|
*/
|
|
if (arg != NULL && IsA(arg, ConvertRowtypeExpr))
|
|
{
|
|
ConvertRowtypeExpr *argcre = (ConvertRowtypeExpr *) arg;
|
|
|
|
arg = (Node *) argcre->arg;
|
|
|
|
/*
|
|
* Make sure an outer implicit conversion can't hide an
|
|
* inner explicit one.
|
|
*/
|
|
if (newcre->convertformat == COERCE_IMPLICIT_CAST)
|
|
newcre->convertformat = argcre->convertformat;
|
|
}
|
|
|
|
newcre->arg = (Expr *) arg;
|
|
|
|
if (arg != NULL && IsA(arg, Const))
|
|
return ece_evaluate_expr((Node *) newcre);
|
|
return (Node *) newcre;
|
|
}
|
|
default:
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* For any node type not handled above, copy the node unchanged but
|
|
* const-simplify its subexpressions. This is the correct thing for node
|
|
* types whose behavior might change between planning and execution, such
|
|
* as CurrentOfExpr. It's also a safe default for new node types not
|
|
* known to this routine.
|
|
*/
|
|
return ece_generic_processing(node);
|
|
}
|
|
|
|
/*
|
|
* Subroutine for eval_const_expressions: check for non-Const nodes.
|
|
*
|
|
* We can abort recursion immediately on finding a non-Const node. This is
|
|
* critical for performance, else eval_const_expressions_mutator would take
|
|
* O(N^2) time on non-simplifiable trees. However, we do need to descend
|
|
* into List nodes since expression_tree_walker sometimes invokes the walker
|
|
* function directly on List subtrees.
|
|
*/
|
|
static bool
|
|
contain_non_const_walker(Node *node, void *context)
|
|
{
|
|
if (node == NULL)
|
|
return false;
|
|
if (IsA(node, Const))
|
|
return false;
|
|
if (IsA(node, List))
|
|
return expression_tree_walker(node, contain_non_const_walker, context);
|
|
/* Otherwise, abort the tree traversal and return true */
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Subroutine for eval_const_expressions: check if a function is OK to evaluate
|
|
*/
|
|
static bool
|
|
ece_function_is_safe(Oid funcid, eval_const_expressions_context *context)
|
|
{
|
|
char provolatile = func_volatile(funcid);
|
|
|
|
/*
|
|
* Ordinarily we are only allowed to simplify immutable functions. But for
|
|
* purposes of estimation, we consider it okay to simplify functions that
|
|
* are merely stable; the risk that the result might change from planning
|
|
* time to execution time is worth taking in preference to not being able
|
|
* to estimate the value at all.
|
|
*/
|
|
if (provolatile == PROVOLATILE_IMMUTABLE)
|
|
return true;
|
|
if (context->estimate && provolatile == PROVOLATILE_STABLE)
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* Subroutine for eval_const_expressions: apply RelabelType if needed
|
|
*/
|
|
static Node *
|
|
apply_const_relabel(Node *arg, Oid rtype, int32 rtypmod, Oid rcollid,
|
|
CoercionForm rformat, int rlocation)
|
|
{
|
|
/*
|
|
* If we find stacked RelabelTypes (eg, from foo::int::oid) we can discard
|
|
* all but the top one, and must do so to ensure that semantically
|
|
* equivalent expressions are equal().
|
|
*/
|
|
while (arg && IsA(arg, RelabelType))
|
|
arg = (Node *) ((RelabelType *) arg)->arg;
|
|
|
|
if (arg && IsA(arg, Const))
|
|
{
|
|
/*
|
|
* If it's a Const, just modify it in-place; since this is part of
|
|
* eval_const_expressions, we want to end up with a simple Const not
|
|
* an expression tree. We assume the Const is newly generated and
|
|
* hence safe to modify.
|
|
*/
|
|
Const *con = (Const *) arg;
|
|
|
|
con->consttype = rtype;
|
|
con->consttypmod = rtypmod;
|
|
con->constcollid = rcollid;
|
|
return (Node *) con;
|
|
}
|
|
else if (exprType(arg) == rtype &&
|
|
exprTypmod(arg) == rtypmod &&
|
|
exprCollation(arg) == rcollid)
|
|
{
|
|
/* Sometimes we find a nest of relabels that net out to nothing. */
|
|
return arg;
|
|
}
|
|
else
|
|
{
|
|
/* Nope, gotta have a RelabelType. */
|
|
RelabelType *newrelabel = makeNode(RelabelType);
|
|
|
|
newrelabel->arg = (Expr *) arg;
|
|
newrelabel->resulttype = rtype;
|
|
newrelabel->resulttypmod = rtypmod;
|
|
newrelabel->resultcollid = rcollid;
|
|
newrelabel->relabelformat = rformat;
|
|
newrelabel->location = rlocation;
|
|
return (Node *) newrelabel;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Subroutine for eval_const_expressions: process arguments of an OR clause
|
|
*
|
|
* This includes flattening of nested ORs as well as recursion to
|
|
* eval_const_expressions to simplify the OR arguments.
|
|
*
|
|
* After simplification, OR arguments are handled as follows:
|
|
* non constant: keep
|
|
* FALSE: drop (does not affect result)
|
|
* TRUE: force result to TRUE
|
|
* NULL: keep only one
|
|
* We must keep one NULL input because OR expressions evaluate to NULL when no
|
|
* input is TRUE and at least one is NULL. We don't actually include the NULL
|
|
* here, that's supposed to be done by the caller.
|
|
*
|
|
* The output arguments *haveNull and *forceTrue must be initialized false
|
|
* by the caller. They will be set true if a NULL constant or TRUE constant,
|
|
* respectively, is detected anywhere in the argument list.
|
|
*/
|
|
static List *
|
|
simplify_or_arguments(List *args,
|
|
eval_const_expressions_context *context,
|
|
bool *haveNull, bool *forceTrue)
|
|
{
|
|
List *newargs = NIL;
|
|
List *unprocessed_args;
|
|
|
|
/*
|
|
* We want to ensure that any OR immediately beneath another OR gets
|
|
* flattened into a single OR-list, so as to simplify later reasoning.
|
|
*
|
|
* To avoid stack overflow from recursion of eval_const_expressions, we
|
|
* resort to some tenseness here: we keep a list of not-yet-processed
|
|
* inputs, and handle flattening of nested ORs by prepending to the to-do
|
|
* list instead of recursing. Now that the parser generates N-argument
|
|
* ORs from simple lists, this complexity is probably less necessary than
|
|
* it once was, but we might as well keep the logic.
|
|
*/
|
|
unprocessed_args = list_copy(args);
|
|
while (unprocessed_args)
|
|
{
|
|
Node *arg = (Node *) linitial(unprocessed_args);
|
|
|
|
unprocessed_args = list_delete_first(unprocessed_args);
|
|
|
|
/* flatten nested ORs as per above comment */
|
|
if (is_orclause(arg))
|
|
{
|
|
List *subargs = ((BoolExpr *) arg)->args;
|
|
List *oldlist = unprocessed_args;
|
|
|
|
unprocessed_args = list_concat_copy(subargs, unprocessed_args);
|
|
/* perhaps-overly-tense code to avoid leaking old lists */
|
|
list_free(oldlist);
|
|
continue;
|
|
}
|
|
|
|
/* If it's not an OR, simplify it */
|
|
arg = eval_const_expressions_mutator(arg, context);
|
|
|
|
/*
|
|
* It is unlikely but not impossible for simplification of a non-OR
|
|
* clause to produce an OR. Recheck, but don't be too tense about it
|
|
* since it's not a mainstream case. In particular we don't worry
|
|
* about const-simplifying the input twice, nor about list leakage.
|
|
*/
|
|
if (is_orclause(arg))
|
|
{
|
|
List *subargs = ((BoolExpr *) arg)->args;
|
|
|
|
unprocessed_args = list_concat_copy(subargs, unprocessed_args);
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* OK, we have a const-simplified non-OR argument. Process it per
|
|
* comments above.
|
|
*/
|
|
if (IsA(arg, Const))
|
|
{
|
|
Const *const_input = (Const *) arg;
|
|
|
|
if (const_input->constisnull)
|
|
*haveNull = true;
|
|
else if (DatumGetBool(const_input->constvalue))
|
|
{
|
|
*forceTrue = true;
|
|
|
|
/*
|
|
* Once we detect a TRUE result we can just exit the loop
|
|
* immediately. However, if we ever add a notion of
|
|
* non-removable functions, we'd need to keep scanning.
|
|
*/
|
|
return NIL;
|
|
}
|
|
/* otherwise, we can drop the constant-false input */
|
|
continue;
|
|
}
|
|
|
|
/* else emit the simplified arg into the result list */
|
|
newargs = lappend(newargs, arg);
|
|
}
|
|
|
|
return newargs;
|
|
}
|
|
|
|
/*
|
|
* Subroutine for eval_const_expressions: process arguments of an AND clause
|
|
*
|
|
* This includes flattening of nested ANDs as well as recursion to
|
|
* eval_const_expressions to simplify the AND arguments.
|
|
*
|
|
* After simplification, AND arguments are handled as follows:
|
|
* non constant: keep
|
|
* TRUE: drop (does not affect result)
|
|
* FALSE: force result to FALSE
|
|
* NULL: keep only one
|
|
* We must keep one NULL input because AND expressions evaluate to NULL when
|
|
* no input is FALSE and at least one is NULL. We don't actually include the
|
|
* NULL here, that's supposed to be done by the caller.
|
|
*
|
|
* The output arguments *haveNull and *forceFalse must be initialized false
|
|
* by the caller. They will be set true if a null constant or false constant,
|
|
* respectively, is detected anywhere in the argument list.
|
|
*/
|
|
static List *
|
|
simplify_and_arguments(List *args,
|
|
eval_const_expressions_context *context,
|
|
bool *haveNull, bool *forceFalse)
|
|
{
|
|
List *newargs = NIL;
|
|
List *unprocessed_args;
|
|
|
|
/* See comments in simplify_or_arguments */
|
|
unprocessed_args = list_copy(args);
|
|
while (unprocessed_args)
|
|
{
|
|
Node *arg = (Node *) linitial(unprocessed_args);
|
|
|
|
unprocessed_args = list_delete_first(unprocessed_args);
|
|
|
|
/* flatten nested ANDs as per above comment */
|
|
if (is_andclause(arg))
|
|
{
|
|
List *subargs = ((BoolExpr *) arg)->args;
|
|
List *oldlist = unprocessed_args;
|
|
|
|
unprocessed_args = list_concat_copy(subargs, unprocessed_args);
|
|
/* perhaps-overly-tense code to avoid leaking old lists */
|
|
list_free(oldlist);
|
|
continue;
|
|
}
|
|
|
|
/* If it's not an AND, simplify it */
|
|
arg = eval_const_expressions_mutator(arg, context);
|
|
|
|
/*
|
|
* It is unlikely but not impossible for simplification of a non-AND
|
|
* clause to produce an AND. Recheck, but don't be too tense about it
|
|
* since it's not a mainstream case. In particular we don't worry
|
|
* about const-simplifying the input twice, nor about list leakage.
|
|
*/
|
|
if (is_andclause(arg))
|
|
{
|
|
List *subargs = ((BoolExpr *) arg)->args;
|
|
|
|
unprocessed_args = list_concat_copy(subargs, unprocessed_args);
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* OK, we have a const-simplified non-AND argument. Process it per
|
|
* comments above.
|
|
*/
|
|
if (IsA(arg, Const))
|
|
{
|
|
Const *const_input = (Const *) arg;
|
|
|
|
if (const_input->constisnull)
|
|
*haveNull = true;
|
|
else if (!DatumGetBool(const_input->constvalue))
|
|
{
|
|
*forceFalse = true;
|
|
|
|
/*
|
|
* Once we detect a FALSE result we can just exit the loop
|
|
* immediately. However, if we ever add a notion of
|
|
* non-removable functions, we'd need to keep scanning.
|
|
*/
|
|
return NIL;
|
|
}
|
|
/* otherwise, we can drop the constant-true input */
|
|
continue;
|
|
}
|
|
|
|
/* else emit the simplified arg into the result list */
|
|
newargs = lappend(newargs, arg);
|
|
}
|
|
|
|
return newargs;
|
|
}
|
|
|
|
/*
|
|
* Subroutine for eval_const_expressions: try to simplify boolean equality
|
|
* or inequality condition
|
|
*
|
|
* Inputs are the operator OID and the simplified arguments to the operator.
|
|
* Returns a simplified expression if successful, or NULL if cannot
|
|
* simplify the expression.
|
|
*
|
|
* The idea here is to reduce "x = true" to "x" and "x = false" to "NOT x",
|
|
* or similarly "x <> true" to "NOT x" and "x <> false" to "x".
|
|
* This is only marginally useful in itself, but doing it in constant folding
|
|
* ensures that we will recognize these forms as being equivalent in, for
|
|
* example, partial index matching.
|
|
*
|
|
* We come here only if simplify_function has failed; therefore we cannot
|
|
* see two constant inputs, nor a constant-NULL input.
|
|
*/
|
|
static Node *
|
|
simplify_boolean_equality(Oid opno, List *args)
|
|
{
|
|
Node *leftop;
|
|
Node *rightop;
|
|
|
|
Assert(list_length(args) == 2);
|
|
leftop = linitial(args);
|
|
rightop = lsecond(args);
|
|
if (leftop && IsA(leftop, Const))
|
|
{
|
|
Assert(!((Const *) leftop)->constisnull);
|
|
if (opno == BooleanEqualOperator)
|
|
{
|
|
if (DatumGetBool(((Const *) leftop)->constvalue))
|
|
return rightop; /* true = foo */
|
|
else
|
|
return negate_clause(rightop); /* false = foo */
|
|
}
|
|
else
|
|
{
|
|
if (DatumGetBool(((Const *) leftop)->constvalue))
|
|
return negate_clause(rightop); /* true <> foo */
|
|
else
|
|
return rightop; /* false <> foo */
|
|
}
|
|
}
|
|
if (rightop && IsA(rightop, Const))
|
|
{
|
|
Assert(!((Const *) rightop)->constisnull);
|
|
if (opno == BooleanEqualOperator)
|
|
{
|
|
if (DatumGetBool(((Const *) rightop)->constvalue))
|
|
return leftop; /* foo = true */
|
|
else
|
|
return negate_clause(leftop); /* foo = false */
|
|
}
|
|
else
|
|
{
|
|
if (DatumGetBool(((Const *) rightop)->constvalue))
|
|
return negate_clause(leftop); /* foo <> true */
|
|
else
|
|
return leftop; /* foo <> false */
|
|
}
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Subroutine for eval_const_expressions: try to simplify a function call
|
|
* (which might originally have been an operator; we don't care)
|
|
*
|
|
* Inputs are the function OID, actual result type OID (which is needed for
|
|
* polymorphic functions), result typmod, result collation, the input
|
|
* collation to use for the function, the original argument list (not
|
|
* const-simplified yet, unless process_args is false), and some flags;
|
|
* also the context data for eval_const_expressions.
|
|
*
|
|
* Returns a simplified expression if successful, or NULL if cannot
|
|
* simplify the function call.
|
|
*
|
|
* This function is also responsible for converting named-notation argument
|
|
* lists into positional notation and/or adding any needed default argument
|
|
* expressions; which is a bit grotty, but it avoids extra fetches of the
|
|
* function's pg_proc tuple. For this reason, the args list is
|
|
* pass-by-reference. Conversion and const-simplification of the args list
|
|
* will be done even if simplification of the function call itself is not
|
|
* possible.
|
|
*/
|
|
static Expr *
|
|
simplify_function(Oid funcid, Oid result_type, int32 result_typmod,
|
|
Oid result_collid, Oid input_collid, List **args_p,
|
|
bool funcvariadic, bool process_args, bool allow_non_const,
|
|
eval_const_expressions_context *context)
|
|
{
|
|
List *args = *args_p;
|
|
HeapTuple func_tuple;
|
|
Form_pg_proc func_form;
|
|
Expr *newexpr;
|
|
|
|
/*
|
|
* We have three strategies for simplification: execute the function to
|
|
* deliver a constant result, use a transform function to generate a
|
|
* substitute node tree, or expand in-line the body of the function
|
|
* definition (which only works for simple SQL-language functions, but
|
|
* that is a common case). Each case needs access to the function's
|
|
* pg_proc tuple, so fetch it just once.
|
|
*
|
|
* Note: the allow_non_const flag suppresses both the second and third
|
|
* strategies; so if !allow_non_const, simplify_function can only return a
|
|
* Const or NULL. Argument-list rewriting happens anyway, though.
|
|
*/
|
|
func_tuple = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
|
|
if (!HeapTupleIsValid(func_tuple))
|
|
elog(ERROR, "cache lookup failed for function %u", funcid);
|
|
func_form = (Form_pg_proc) GETSTRUCT(func_tuple);
|
|
|
|
/*
|
|
* Process the function arguments, unless the caller did it already.
|
|
*
|
|
* Here we must deal with named or defaulted arguments, and then
|
|
* recursively apply eval_const_expressions to the whole argument list.
|
|
*/
|
|
if (process_args)
|
|
{
|
|
args = expand_function_arguments(args, result_type, func_tuple);
|
|
args = (List *) expression_tree_mutator((Node *) args,
|
|
eval_const_expressions_mutator,
|
|
(void *) context);
|
|
/* Argument processing done, give it back to the caller */
|
|
*args_p = args;
|
|
}
|
|
|
|
/* Now attempt simplification of the function call proper. */
|
|
|
|
newexpr = evaluate_function(funcid, result_type, result_typmod,
|
|
result_collid, input_collid,
|
|
args, funcvariadic,
|
|
func_tuple, context);
|
|
|
|
if (!newexpr && allow_non_const && OidIsValid(func_form->prosupport))
|
|
{
|
|
/*
|
|
* Build a SupportRequestSimplify node to pass to the support
|
|
* function, pointing to a dummy FuncExpr node containing the
|
|
* simplified arg list. We use this approach to present a uniform
|
|
* interface to the support function regardless of how the target
|
|
* function is actually being invoked.
|
|
*/
|
|
SupportRequestSimplify req;
|
|
FuncExpr fexpr;
|
|
|
|
fexpr.xpr.type = T_FuncExpr;
|
|
fexpr.funcid = funcid;
|
|
fexpr.funcresulttype = result_type;
|
|
fexpr.funcretset = func_form->proretset;
|
|
fexpr.funcvariadic = funcvariadic;
|
|
fexpr.funcformat = COERCE_EXPLICIT_CALL;
|
|
fexpr.funccollid = result_collid;
|
|
fexpr.inputcollid = input_collid;
|
|
fexpr.args = args;
|
|
fexpr.location = -1;
|
|
|
|
req.type = T_SupportRequestSimplify;
|
|
req.root = context->root;
|
|
req.fcall = &fexpr;
|
|
|
|
newexpr = (Expr *)
|
|
DatumGetPointer(OidFunctionCall1(func_form->prosupport,
|
|
PointerGetDatum(&req)));
|
|
|
|
/* catch a possible API misunderstanding */
|
|
Assert(newexpr != (Expr *) &fexpr);
|
|
}
|
|
|
|
if (!newexpr && allow_non_const)
|
|
newexpr = inline_function(funcid, result_type, result_collid,
|
|
input_collid, args, funcvariadic,
|
|
func_tuple, context);
|
|
|
|
ReleaseSysCache(func_tuple);
|
|
|
|
return newexpr;
|
|
}
|
|
|
|
/*
|
|
* expand_function_arguments: convert named-notation args to positional args
|
|
* and/or insert default args, as needed
|
|
*
|
|
* If we need to change anything, the input argument list is copied, not
|
|
* modified.
|
|
*
|
|
* Note: this gets applied to operator argument lists too, even though the
|
|
* cases it handles should never occur there. This should be OK since it
|
|
* will fall through very quickly if there's nothing to do.
|
|
*/
|
|
List *
|
|
expand_function_arguments(List *args, Oid result_type, HeapTuple func_tuple)
|
|
{
|
|
Form_pg_proc funcform = (Form_pg_proc) GETSTRUCT(func_tuple);
|
|
bool has_named_args = false;
|
|
ListCell *lc;
|
|
|
|
/* Do we have any named arguments? */
|
|
foreach(lc, args)
|
|
{
|
|
Node *arg = (Node *) lfirst(lc);
|
|
|
|
if (IsA(arg, NamedArgExpr))
|
|
{
|
|
has_named_args = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* If so, we must apply reorder_function_arguments */
|
|
if (has_named_args)
|
|
{
|
|
args = reorder_function_arguments(args, func_tuple);
|
|
/* Recheck argument types and add casts if needed */
|
|
recheck_cast_function_args(args, result_type, func_tuple);
|
|
}
|
|
else if (list_length(args) < funcform->pronargs)
|
|
{
|
|
/* No named args, but we seem to be short some defaults */
|
|
args = add_function_defaults(args, func_tuple);
|
|
/* Recheck argument types and add casts if needed */
|
|
recheck_cast_function_args(args, result_type, func_tuple);
|
|
}
|
|
|
|
return args;
|
|
}
|
|
|
|
/*
|
|
* reorder_function_arguments: convert named-notation args to positional args
|
|
*
|
|
* This function also inserts default argument values as needed, since it's
|
|
* impossible to form a truly valid positional call without that.
|
|
*/
|
|
static List *
|
|
reorder_function_arguments(List *args, HeapTuple func_tuple)
|
|
{
|
|
Form_pg_proc funcform = (Form_pg_proc) GETSTRUCT(func_tuple);
|
|
int pronargs = funcform->pronargs;
|
|
int nargsprovided = list_length(args);
|
|
Node *argarray[FUNC_MAX_ARGS];
|
|
ListCell *lc;
|
|
int i;
|
|
|
|
Assert(nargsprovided <= pronargs);
|
|
if (pronargs > FUNC_MAX_ARGS)
|
|
elog(ERROR, "too many function arguments");
|
|
MemSet(argarray, 0, pronargs * sizeof(Node *));
|
|
|
|
/* Deconstruct the argument list into an array indexed by argnumber */
|
|
i = 0;
|
|
foreach(lc, args)
|
|
{
|
|
Node *arg = (Node *) lfirst(lc);
|
|
|
|
if (!IsA(arg, NamedArgExpr))
|
|
{
|
|
/* positional argument, assumed to precede all named args */
|
|
Assert(argarray[i] == NULL);
|
|
argarray[i++] = arg;
|
|
}
|
|
else
|
|
{
|
|
NamedArgExpr *na = (NamedArgExpr *) arg;
|
|
|
|
Assert(argarray[na->argnumber] == NULL);
|
|
argarray[na->argnumber] = (Node *) na->arg;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Fetch default expressions, if needed, and insert into array at proper
|
|
* locations (they aren't necessarily consecutive or all used)
|
|
*/
|
|
if (nargsprovided < pronargs)
|
|
{
|
|
List *defaults = fetch_function_defaults(func_tuple);
|
|
|
|
i = pronargs - funcform->pronargdefaults;
|
|
foreach(lc, defaults)
|
|
{
|
|
if (argarray[i] == NULL)
|
|
argarray[i] = (Node *) lfirst(lc);
|
|
i++;
|
|
}
|
|
}
|
|
|
|
/* Now reconstruct the args list in proper order */
|
|
args = NIL;
|
|
for (i = 0; i < pronargs; i++)
|
|
{
|
|
Assert(argarray[i] != NULL);
|
|
args = lappend(args, argarray[i]);
|
|
}
|
|
|
|
return args;
|
|
}
|
|
|
|
/*
|
|
* add_function_defaults: add missing function arguments from its defaults
|
|
*
|
|
* This is used only when the argument list was positional to begin with,
|
|
* and so we know we just need to add defaults at the end.
|
|
*/
|
|
static List *
|
|
add_function_defaults(List *args, HeapTuple func_tuple)
|
|
{
|
|
Form_pg_proc funcform = (Form_pg_proc) GETSTRUCT(func_tuple);
|
|
int nargsprovided = list_length(args);
|
|
List *defaults;
|
|
int ndelete;
|
|
|
|
/* Get all the default expressions from the pg_proc tuple */
|
|
defaults = fetch_function_defaults(func_tuple);
|
|
|
|
/* Delete any unused defaults from the list */
|
|
ndelete = nargsprovided + list_length(defaults) - funcform->pronargs;
|
|
if (ndelete < 0)
|
|
elog(ERROR, "not enough default arguments");
|
|
if (ndelete > 0)
|
|
defaults = list_copy_tail(defaults, ndelete);
|
|
|
|
/* And form the combined argument list, not modifying the input list */
|
|
return list_concat_copy(args, defaults);
|
|
}
|
|
|
|
/*
|
|
* fetch_function_defaults: get function's default arguments as expression list
|
|
*/
|
|
static List *
|
|
fetch_function_defaults(HeapTuple func_tuple)
|
|
{
|
|
List *defaults;
|
|
Datum proargdefaults;
|
|
bool isnull;
|
|
char *str;
|
|
|
|
/* The error cases here shouldn't happen, but check anyway */
|
|
proargdefaults = SysCacheGetAttr(PROCOID, func_tuple,
|
|
Anum_pg_proc_proargdefaults,
|
|
&isnull);
|
|
if (isnull)
|
|
elog(ERROR, "not enough default arguments");
|
|
str = TextDatumGetCString(proargdefaults);
|
|
defaults = castNode(List, stringToNode(str));
|
|
pfree(str);
|
|
return defaults;
|
|
}
|
|
|
|
/*
|
|
* recheck_cast_function_args: recheck function args and typecast as needed
|
|
* after adding defaults.
|
|
*
|
|
* It is possible for some of the defaulted arguments to be polymorphic;
|
|
* therefore we can't assume that the default expressions have the correct
|
|
* data types already. We have to re-resolve polymorphics and do coercion
|
|
* just like the parser did.
|
|
*
|
|
* This should be a no-op if there are no polymorphic arguments,
|
|
* but we do it anyway to be sure.
|
|
*
|
|
* Note: if any casts are needed, the args list is modified in-place;
|
|
* caller should have already copied the list structure.
|
|
*/
|
|
static void
|
|
recheck_cast_function_args(List *args, Oid result_type, HeapTuple func_tuple)
|
|
{
|
|
Form_pg_proc funcform = (Form_pg_proc) GETSTRUCT(func_tuple);
|
|
int nargs;
|
|
Oid actual_arg_types[FUNC_MAX_ARGS];
|
|
Oid declared_arg_types[FUNC_MAX_ARGS];
|
|
Oid rettype;
|
|
ListCell *lc;
|
|
|
|
if (list_length(args) > FUNC_MAX_ARGS)
|
|
elog(ERROR, "too many function arguments");
|
|
nargs = 0;
|
|
foreach(lc, args)
|
|
{
|
|
actual_arg_types[nargs++] = exprType((Node *) lfirst(lc));
|
|
}
|
|
Assert(nargs == funcform->pronargs);
|
|
memcpy(declared_arg_types, funcform->proargtypes.values,
|
|
funcform->pronargs * sizeof(Oid));
|
|
rettype = enforce_generic_type_consistency(actual_arg_types,
|
|
declared_arg_types,
|
|
nargs,
|
|
funcform->prorettype,
|
|
false);
|
|
/* let's just check we got the same answer as the parser did ... */
|
|
if (rettype != result_type)
|
|
elog(ERROR, "function's resolved result type changed during planning");
|
|
|
|
/* perform any necessary typecasting of arguments */
|
|
make_fn_arguments(NULL, args, actual_arg_types, declared_arg_types);
|
|
}
|
|
|
|
/*
|
|
* evaluate_function: try to pre-evaluate a function call
|
|
*
|
|
* We can do this if the function is strict and has any constant-null inputs
|
|
* (just return a null constant), or if the function is immutable and has all
|
|
* constant inputs (call it and return the result as a Const node). In
|
|
* estimation mode we are willing to pre-evaluate stable functions too.
|
|
*
|
|
* Returns a simplified expression if successful, or NULL if cannot
|
|
* simplify the function.
|
|
*/
|
|
static Expr *
|
|
evaluate_function(Oid funcid, Oid result_type, int32 result_typmod,
|
|
Oid result_collid, Oid input_collid, List *args,
|
|
bool funcvariadic,
|
|
HeapTuple func_tuple,
|
|
eval_const_expressions_context *context)
|
|
{
|
|
Form_pg_proc funcform = (Form_pg_proc) GETSTRUCT(func_tuple);
|
|
bool has_nonconst_input = false;
|
|
bool has_null_input = false;
|
|
ListCell *arg;
|
|
FuncExpr *newexpr;
|
|
|
|
/*
|
|
* Can't simplify if it returns a set.
|
|
*/
|
|
if (funcform->proretset)
|
|
return NULL;
|
|
|
|
/*
|
|
* Can't simplify if it returns RECORD. The immediate problem is that it
|
|
* will be needing an expected tupdesc which we can't supply here.
|
|
*
|
|
* In the case where it has OUT parameters, it could get by without an
|
|
* expected tupdesc, but we still have issues: get_expr_result_type()
|
|
* doesn't know how to extract type info from a RECORD constant, and in
|
|
* the case of a NULL function result there doesn't seem to be any clean
|
|
* way to fix that. In view of the likelihood of there being still other
|
|
* gotchas, seems best to leave the function call unreduced.
|
|
*/
|
|
if (funcform->prorettype == RECORDOID)
|
|
return NULL;
|
|
|
|
/*
|
|
* Check for constant inputs and especially constant-NULL inputs.
|
|
*/
|
|
foreach(arg, args)
|
|
{
|
|
if (IsA(lfirst(arg), Const))
|
|
has_null_input |= ((Const *) lfirst(arg))->constisnull;
|
|
else
|
|
has_nonconst_input = true;
|
|
}
|
|
|
|
/*
|
|
* If the function is strict and has a constant-NULL input, it will never
|
|
* be called at all, so we can replace the call by a NULL constant, even
|
|
* if there are other inputs that aren't constant, and even if the
|
|
* function is not otherwise immutable.
|
|
*/
|
|
if (funcform->proisstrict && has_null_input)
|
|
return (Expr *) makeNullConst(result_type, result_typmod,
|
|
result_collid);
|
|
|
|
/*
|
|
* Otherwise, can simplify only if all inputs are constants. (For a
|
|
* non-strict function, constant NULL inputs are treated the same as
|
|
* constant non-NULL inputs.)
|
|
*/
|
|
if (has_nonconst_input)
|
|
return NULL;
|
|
|
|
/*
|
|
* Ordinarily we are only allowed to simplify immutable functions. But for
|
|
* purposes of estimation, we consider it okay to simplify functions that
|
|
* are merely stable; the risk that the result might change from planning
|
|
* time to execution time is worth taking in preference to not being able
|
|
* to estimate the value at all.
|
|
*/
|
|
if (funcform->provolatile == PROVOLATILE_IMMUTABLE)
|
|
/* okay */ ;
|
|
else if (context->estimate && funcform->provolatile == PROVOLATILE_STABLE)
|
|
/* okay */ ;
|
|
else
|
|
return NULL;
|
|
|
|
/*
|
|
* OK, looks like we can simplify this operator/function.
|
|
*
|
|
* Build a new FuncExpr node containing the already-simplified arguments.
|
|
*/
|
|
newexpr = makeNode(FuncExpr);
|
|
newexpr->funcid = funcid;
|
|
newexpr->funcresulttype = result_type;
|
|
newexpr->funcretset = false;
|
|
newexpr->funcvariadic = funcvariadic;
|
|
newexpr->funcformat = COERCE_EXPLICIT_CALL; /* doesn't matter */
|
|
newexpr->funccollid = result_collid; /* doesn't matter */
|
|
newexpr->inputcollid = input_collid;
|
|
newexpr->args = args;
|
|
newexpr->location = -1;
|
|
|
|
return evaluate_expr((Expr *) newexpr, result_type, result_typmod,
|
|
result_collid);
|
|
}
|
|
|
|
/*
|
|
* inline_function: try to expand a function call inline
|
|
*
|
|
* If the function is a sufficiently simple SQL-language function
|
|
* (just "SELECT expression"), then we can inline it and avoid the rather
|
|
* high per-call overhead of SQL functions. Furthermore, this can expose
|
|
* opportunities for constant-folding within the function expression.
|
|
*
|
|
* We have to beware of some special cases however. A directly or
|
|
* indirectly recursive function would cause us to recurse forever,
|
|
* so we keep track of which functions we are already expanding and
|
|
* do not re-expand them. Also, if a parameter is used more than once
|
|
* in the SQL-function body, we require it not to contain any volatile
|
|
* functions (volatiles might deliver inconsistent answers) nor to be
|
|
* unreasonably expensive to evaluate. The expensiveness check not only
|
|
* prevents us from doing multiple evaluations of an expensive parameter
|
|
* at runtime, but is a safety value to limit growth of an expression due
|
|
* to repeated inlining.
|
|
*
|
|
* We must also beware of changing the volatility or strictness status of
|
|
* functions by inlining them.
|
|
*
|
|
* Also, at the moment we can't inline functions returning RECORD. This
|
|
* doesn't work in the general case because it discards information such
|
|
* as OUT-parameter declarations.
|
|
*
|
|
* Also, context-dependent expression nodes in the argument list are trouble.
|
|
*
|
|
* Returns a simplified expression if successful, or NULL if cannot
|
|
* simplify the function.
|
|
*/
|
|
static Expr *
|
|
inline_function(Oid funcid, Oid result_type, Oid result_collid,
|
|
Oid input_collid, List *args,
|
|
bool funcvariadic,
|
|
HeapTuple func_tuple,
|
|
eval_const_expressions_context *context)
|
|
{
|
|
Form_pg_proc funcform = (Form_pg_proc) GETSTRUCT(func_tuple);
|
|
char *src;
|
|
Datum tmp;
|
|
bool isNull;
|
|
MemoryContext oldcxt;
|
|
MemoryContext mycxt;
|
|
inline_error_callback_arg callback_arg;
|
|
ErrorContextCallback sqlerrcontext;
|
|
FuncExpr *fexpr;
|
|
SQLFunctionParseInfoPtr pinfo;
|
|
TupleDesc rettupdesc;
|
|
ParseState *pstate;
|
|
List *raw_parsetree_list;
|
|
List *querytree_list;
|
|
Query *querytree;
|
|
Node *newexpr;
|
|
int *usecounts;
|
|
ListCell *arg;
|
|
int i;
|
|
|
|
/*
|
|
* Forget it if the function is not SQL-language or has other showstopper
|
|
* properties. (The prokind and nargs checks are just paranoia.)
|
|
*/
|
|
if (funcform->prolang != SQLlanguageId ||
|
|
funcform->prokind != PROKIND_FUNCTION ||
|
|
funcform->prosecdef ||
|
|
funcform->proretset ||
|
|
funcform->prorettype == RECORDOID ||
|
|
!heap_attisnull(func_tuple, Anum_pg_proc_proconfig, NULL) ||
|
|
funcform->pronargs != list_length(args))
|
|
return NULL;
|
|
|
|
/* Check for recursive function, and give up trying to expand if so */
|
|
if (list_member_oid(context->active_fns, funcid))
|
|
return NULL;
|
|
|
|
/* Check permission to call function (fail later, if not) */
|
|
if (pg_proc_aclcheck(funcid, GetUserId(), ACL_EXECUTE) != ACLCHECK_OK)
|
|
return NULL;
|
|
|
|
/* Check whether a plugin wants to hook function entry/exit */
|
|
if (FmgrHookIsNeeded(funcid))
|
|
return NULL;
|
|
|
|
/*
|
|
* Make a temporary memory context, so that we don't leak all the stuff
|
|
* that parsing might create.
|
|
*/
|
|
mycxt = AllocSetContextCreate(CurrentMemoryContext,
|
|
"inline_function",
|
|
ALLOCSET_DEFAULT_SIZES);
|
|
oldcxt = MemoryContextSwitchTo(mycxt);
|
|
|
|
/* Fetch the function body */
|
|
tmp = SysCacheGetAttr(PROCOID,
|
|
func_tuple,
|
|
Anum_pg_proc_prosrc,
|
|
&isNull);
|
|
if (isNull)
|
|
elog(ERROR, "null prosrc for function %u", funcid);
|
|
src = TextDatumGetCString(tmp);
|
|
|
|
/*
|
|
* Setup error traceback support for ereport(). This is so that we can
|
|
* finger the function that bad information came from.
|
|
*/
|
|
callback_arg.proname = NameStr(funcform->proname);
|
|
callback_arg.prosrc = src;
|
|
|
|
sqlerrcontext.callback = sql_inline_error_callback;
|
|
sqlerrcontext.arg = (void *) &callback_arg;
|
|
sqlerrcontext.previous = error_context_stack;
|
|
error_context_stack = &sqlerrcontext;
|
|
|
|
/*
|
|
* Set up to handle parameters while parsing the function body. We need a
|
|
* dummy FuncExpr node containing the already-simplified arguments to pass
|
|
* to prepare_sql_fn_parse_info. (In some cases we don't really need
|
|
* that, but for simplicity we always build it.)
|
|
*/
|
|
fexpr = makeNode(FuncExpr);
|
|
fexpr->funcid = funcid;
|
|
fexpr->funcresulttype = result_type;
|
|
fexpr->funcretset = false;
|
|
fexpr->funcvariadic = funcvariadic;
|
|
fexpr->funcformat = COERCE_EXPLICIT_CALL; /* doesn't matter */
|
|
fexpr->funccollid = result_collid; /* doesn't matter */
|
|
fexpr->inputcollid = input_collid;
|
|
fexpr->args = args;
|
|
fexpr->location = -1;
|
|
|
|
pinfo = prepare_sql_fn_parse_info(func_tuple,
|
|
(Node *) fexpr,
|
|
input_collid);
|
|
|
|
/* fexpr also provides a convenient way to resolve a composite result */
|
|
(void) get_expr_result_type((Node *) fexpr,
|
|
NULL,
|
|
&rettupdesc);
|
|
|
|
/*
|
|
* We just do parsing and parse analysis, not rewriting, because rewriting
|
|
* will not affect table-free-SELECT-only queries, which is all that we
|
|
* care about. Also, we can punt as soon as we detect more than one
|
|
* command in the function body.
|
|
*/
|
|
raw_parsetree_list = pg_parse_query(src);
|
|
if (list_length(raw_parsetree_list) != 1)
|
|
goto fail;
|
|
|
|
pstate = make_parsestate(NULL);
|
|
pstate->p_sourcetext = src;
|
|
sql_fn_parser_setup(pstate, pinfo);
|
|
|
|
querytree = transformTopLevelStmt(pstate, linitial(raw_parsetree_list));
|
|
|
|
free_parsestate(pstate);
|
|
|
|
/*
|
|
* The single command must be a simple "SELECT expression".
|
|
*
|
|
* Note: if you change the tests involved in this, see also plpgsql's
|
|
* exec_simple_check_plan(). That generally needs to have the same idea
|
|
* of what's a "simple expression", so that inlining a function that
|
|
* previously wasn't inlined won't change plpgsql's conclusion.
|
|
*/
|
|
if (!IsA(querytree, Query) ||
|
|
querytree->commandType != CMD_SELECT ||
|
|
querytree->hasAggs ||
|
|
querytree->hasWindowFuncs ||
|
|
querytree->hasTargetSRFs ||
|
|
querytree->hasSubLinks ||
|
|
querytree->cteList ||
|
|
querytree->rtable ||
|
|
querytree->jointree->fromlist ||
|
|
querytree->jointree->quals ||
|
|
querytree->groupClause ||
|
|
querytree->groupingSets ||
|
|
querytree->havingQual ||
|
|
querytree->windowClause ||
|
|
querytree->distinctClause ||
|
|
querytree->sortClause ||
|
|
querytree->limitOffset ||
|
|
querytree->limitCount ||
|
|
querytree->setOperations ||
|
|
list_length(querytree->targetList) != 1)
|
|
goto fail;
|
|
|
|
/*
|
|
* Make sure the function (still) returns what it's declared to. This
|
|
* will raise an error if wrong, but that's okay since the function would
|
|
* fail at runtime anyway. Note that check_sql_fn_retval will also insert
|
|
* a coercion if needed to make the tlist expression match the declared
|
|
* type of the function.
|
|
*
|
|
* Note: we do not try this until we have verified that no rewriting was
|
|
* needed; that's probably not important, but let's be careful.
|
|
*/
|
|
querytree_list = list_make1(querytree);
|
|
if (check_sql_fn_retval(querytree_list, result_type, rettupdesc,
|
|
false, NULL))
|
|
goto fail; /* reject whole-tuple-result cases */
|
|
|
|
/*
|
|
* Given the tests above, check_sql_fn_retval shouldn't have decided to
|
|
* inject a projection step, but let's just make sure.
|
|
*/
|
|
if (querytree != linitial(querytree_list))
|
|
goto fail;
|
|
|
|
/* Now we can grab the tlist expression */
|
|
newexpr = (Node *) ((TargetEntry *) linitial(querytree->targetList))->expr;
|
|
|
|
/*
|
|
* If the SQL function returns VOID, we can only inline it if it is a
|
|
* SELECT of an expression returning VOID (ie, it's just a redirection to
|
|
* another VOID-returning function). In all non-VOID-returning cases,
|
|
* check_sql_fn_retval should ensure that newexpr returns the function's
|
|
* declared result type, so this test shouldn't fail otherwise; but we may
|
|
* as well cope gracefully if it does.
|
|
*/
|
|
if (exprType(newexpr) != result_type)
|
|
goto fail;
|
|
|
|
/*
|
|
* Additional validity checks on the expression. It mustn't be more
|
|
* volatile than the surrounding function (this is to avoid breaking hacks
|
|
* that involve pretending a function is immutable when it really ain't).
|
|
* If the surrounding function is declared strict, then the expression
|
|
* must contain only strict constructs and must use all of the function
|
|
* parameters (this is overkill, but an exact analysis is hard).
|
|
*/
|
|
if (funcform->provolatile == PROVOLATILE_IMMUTABLE &&
|
|
contain_mutable_functions(newexpr))
|
|
goto fail;
|
|
else if (funcform->provolatile == PROVOLATILE_STABLE &&
|
|
contain_volatile_functions(newexpr))
|
|
goto fail;
|
|
|
|
if (funcform->proisstrict &&
|
|
contain_nonstrict_functions(newexpr))
|
|
goto fail;
|
|
|
|
/*
|
|
* If any parameter expression contains a context-dependent node, we can't
|
|
* inline, for fear of putting such a node into the wrong context.
|
|
*/
|
|
if (contain_context_dependent_node((Node *) args))
|
|
goto fail;
|
|
|
|
/*
|
|
* We may be able to do it; there are still checks on parameter usage to
|
|
* make, but those are most easily done in combination with the actual
|
|
* substitution of the inputs. So start building expression with inputs
|
|
* substituted.
|
|
*/
|
|
usecounts = (int *) palloc0(funcform->pronargs * sizeof(int));
|
|
newexpr = substitute_actual_parameters(newexpr, funcform->pronargs,
|
|
args, usecounts);
|
|
|
|
/* Now check for parameter usage */
|
|
i = 0;
|
|
foreach(arg, args)
|
|
{
|
|
Node *param = lfirst(arg);
|
|
|
|
if (usecounts[i] == 0)
|
|
{
|
|
/* Param not used at all: uncool if func is strict */
|
|
if (funcform->proisstrict)
|
|
goto fail;
|
|
}
|
|
else if (usecounts[i] != 1)
|
|
{
|
|
/* Param used multiple times: uncool if expensive or volatile */
|
|
QualCost eval_cost;
|
|
|
|
/*
|
|
* We define "expensive" as "contains any subplan or more than 10
|
|
* operators". Note that the subplan search has to be done
|
|
* explicitly, since cost_qual_eval() will barf on unplanned
|
|
* subselects.
|
|
*/
|
|
if (contain_subplans(param))
|
|
goto fail;
|
|
cost_qual_eval(&eval_cost, list_make1(param), NULL);
|
|
if (eval_cost.startup + eval_cost.per_tuple >
|
|
10 * cpu_operator_cost)
|
|
goto fail;
|
|
|
|
/*
|
|
* Check volatility last since this is more expensive than the
|
|
* above tests
|
|
*/
|
|
if (contain_volatile_functions(param))
|
|
goto fail;
|
|
}
|
|
i++;
|
|
}
|
|
|
|
/*
|
|
* Whew --- we can make the substitution. Copy the modified expression
|
|
* out of the temporary memory context, and clean up.
|
|
*/
|
|
MemoryContextSwitchTo(oldcxt);
|
|
|
|
newexpr = copyObject(newexpr);
|
|
|
|
MemoryContextDelete(mycxt);
|
|
|
|
/*
|
|
* If the result is of a collatable type, force the result to expose the
|
|
* correct collation. In most cases this does not matter, but it's
|
|
* possible that the function result is used directly as a sort key or in
|
|
* other places where we expect exprCollation() to tell the truth.
|
|
*/
|
|
if (OidIsValid(result_collid))
|
|
{
|
|
Oid exprcoll = exprCollation(newexpr);
|
|
|
|
if (OidIsValid(exprcoll) && exprcoll != result_collid)
|
|
{
|
|
CollateExpr *newnode = makeNode(CollateExpr);
|
|
|
|
newnode->arg = (Expr *) newexpr;
|
|
newnode->collOid = result_collid;
|
|
newnode->location = -1;
|
|
|
|
newexpr = (Node *) newnode;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Since there is now no trace of the function in the plan tree, we must
|
|
* explicitly record the plan's dependency on the function.
|
|
*/
|
|
if (context->root)
|
|
record_plan_function_dependency(context->root, funcid);
|
|
|
|
/*
|
|
* Recursively try to simplify the modified expression. Here we must add
|
|
* the current function to the context list of active functions.
|
|
*/
|
|
context->active_fns = lappend_oid(context->active_fns, funcid);
|
|
newexpr = eval_const_expressions_mutator(newexpr, context);
|
|
context->active_fns = list_delete_last(context->active_fns);
|
|
|
|
error_context_stack = sqlerrcontext.previous;
|
|
|
|
return (Expr *) newexpr;
|
|
|
|
/* Here if func is not inlinable: release temp memory and return NULL */
|
|
fail:
|
|
MemoryContextSwitchTo(oldcxt);
|
|
MemoryContextDelete(mycxt);
|
|
error_context_stack = sqlerrcontext.previous;
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Replace Param nodes by appropriate actual parameters
|
|
*/
|
|
static Node *
|
|
substitute_actual_parameters(Node *expr, int nargs, List *args,
|
|
int *usecounts)
|
|
{
|
|
substitute_actual_parameters_context context;
|
|
|
|
context.nargs = nargs;
|
|
context.args = args;
|
|
context.usecounts = usecounts;
|
|
|
|
return substitute_actual_parameters_mutator(expr, &context);
|
|
}
|
|
|
|
static Node *
|
|
substitute_actual_parameters_mutator(Node *node,
|
|
substitute_actual_parameters_context *context)
|
|
{
|
|
if (node == NULL)
|
|
return NULL;
|
|
if (IsA(node, Param))
|
|
{
|
|
Param *param = (Param *) node;
|
|
|
|
if (param->paramkind != PARAM_EXTERN)
|
|
elog(ERROR, "unexpected paramkind: %d", (int) param->paramkind);
|
|
if (param->paramid <= 0 || param->paramid > context->nargs)
|
|
elog(ERROR, "invalid paramid: %d", param->paramid);
|
|
|
|
/* Count usage of parameter */
|
|
context->usecounts[param->paramid - 1]++;
|
|
|
|
/* Select the appropriate actual arg and replace the Param with it */
|
|
/* We don't need to copy at this time (it'll get done later) */
|
|
return list_nth(context->args, param->paramid - 1);
|
|
}
|
|
return expression_tree_mutator(node, substitute_actual_parameters_mutator,
|
|
(void *) context);
|
|
}
|
|
|
|
/*
|
|
* error context callback to let us supply a call-stack traceback
|
|
*/
|
|
static void
|
|
sql_inline_error_callback(void *arg)
|
|
{
|
|
inline_error_callback_arg *callback_arg = (inline_error_callback_arg *) arg;
|
|
int syntaxerrposition;
|
|
|
|
/* If it's a syntax error, convert to internal syntax error report */
|
|
syntaxerrposition = geterrposition();
|
|
if (syntaxerrposition > 0)
|
|
{
|
|
errposition(0);
|
|
internalerrposition(syntaxerrposition);
|
|
internalerrquery(callback_arg->prosrc);
|
|
}
|
|
|
|
errcontext("SQL function \"%s\" during inlining", callback_arg->proname);
|
|
}
|
|
|
|
/*
|
|
* evaluate_expr: pre-evaluate a constant expression
|
|
*
|
|
* We use the executor's routine ExecEvalExpr() to avoid duplication of
|
|
* code and ensure we get the same result as the executor would get.
|
|
*/
|
|
Expr *
|
|
evaluate_expr(Expr *expr, Oid result_type, int32 result_typmod,
|
|
Oid result_collation)
|
|
{
|
|
EState *estate;
|
|
ExprState *exprstate;
|
|
MemoryContext oldcontext;
|
|
Datum const_val;
|
|
bool const_is_null;
|
|
int16 resultTypLen;
|
|
bool resultTypByVal;
|
|
|
|
/*
|
|
* To use the executor, we need an EState.
|
|
*/
|
|
estate = CreateExecutorState();
|
|
|
|
/* We can use the estate's working context to avoid memory leaks. */
|
|
oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
|
|
|
|
/* Make sure any opfuncids are filled in. */
|
|
fix_opfuncids((Node *) expr);
|
|
|
|
/*
|
|
* Prepare expr for execution. (Note: we can't use ExecPrepareExpr
|
|
* because it'd result in recursively invoking eval_const_expressions.)
|
|
*/
|
|
exprstate = ExecInitExpr(expr, NULL);
|
|
|
|
/*
|
|
* And evaluate it.
|
|
*
|
|
* It is OK to use a default econtext because none of the ExecEvalExpr()
|
|
* code used in this situation will use econtext. That might seem
|
|
* fortuitous, but it's not so unreasonable --- a constant expression does
|
|
* not depend on context, by definition, n'est ce pas?
|
|
*/
|
|
const_val = ExecEvalExprSwitchContext(exprstate,
|
|
GetPerTupleExprContext(estate),
|
|
&const_is_null);
|
|
|
|
/* Get info needed about result datatype */
|
|
get_typlenbyval(result_type, &resultTypLen, &resultTypByVal);
|
|
|
|
/* Get back to outer memory context */
|
|
MemoryContextSwitchTo(oldcontext);
|
|
|
|
/*
|
|
* Must copy result out of sub-context used by expression eval.
|
|
*
|
|
* Also, if it's varlena, forcibly detoast it. This protects us against
|
|
* storing TOAST pointers into plans that might outlive the referenced
|
|
* data. (makeConst would handle detoasting anyway, but it's worth a few
|
|
* extra lines here so that we can do the copy and detoast in one step.)
|
|
*/
|
|
if (!const_is_null)
|
|
{
|
|
if (resultTypLen == -1)
|
|
const_val = PointerGetDatum(PG_DETOAST_DATUM_COPY(const_val));
|
|
else
|
|
const_val = datumCopy(const_val, resultTypByVal, resultTypLen);
|
|
}
|
|
|
|
/* Release all the junk we just created */
|
|
FreeExecutorState(estate);
|
|
|
|
/*
|
|
* Make the constant result node.
|
|
*/
|
|
return (Expr *) makeConst(result_type, result_typmod, result_collation,
|
|
resultTypLen,
|
|
const_val, const_is_null,
|
|
resultTypByVal);
|
|
}
|
|
|
|
|
|
/*
|
|
* inline_set_returning_function
|
|
* Attempt to "inline" a set-returning function in the FROM clause.
|
|
*
|
|
* "rte" is an RTE_FUNCTION rangetable entry. If it represents a call of a
|
|
* set-returning SQL function that can safely be inlined, expand the function
|
|
* and return the substitute Query structure. Otherwise, return NULL.
|
|
*
|
|
* We assume that the RTE's expression has already been put through
|
|
* eval_const_expressions(), which among other things will take care of
|
|
* default arguments and named-argument notation.
|
|
*
|
|
* This has a good deal of similarity to inline_function(), but that's
|
|
* for the non-set-returning case, and there are enough differences to
|
|
* justify separate functions.
|
|
*/
|
|
Query *
|
|
inline_set_returning_function(PlannerInfo *root, RangeTblEntry *rte)
|
|
{
|
|
RangeTblFunction *rtfunc;
|
|
FuncExpr *fexpr;
|
|
Oid func_oid;
|
|
HeapTuple func_tuple;
|
|
Form_pg_proc funcform;
|
|
char *src;
|
|
Datum tmp;
|
|
bool isNull;
|
|
MemoryContext oldcxt;
|
|
MemoryContext mycxt;
|
|
inline_error_callback_arg callback_arg;
|
|
ErrorContextCallback sqlerrcontext;
|
|
SQLFunctionParseInfoPtr pinfo;
|
|
TypeFuncClass functypclass;
|
|
TupleDesc rettupdesc;
|
|
List *raw_parsetree_list;
|
|
List *querytree_list;
|
|
Query *querytree;
|
|
|
|
Assert(rte->rtekind == RTE_FUNCTION);
|
|
|
|
/*
|
|
* It doesn't make a lot of sense for a SQL SRF to refer to itself in its
|
|
* own FROM clause, since that must cause infinite recursion at runtime.
|
|
* It will cause this code to recurse too, so check for stack overflow.
|
|
* (There's no need to do more.)
|
|
*/
|
|
check_stack_depth();
|
|
|
|
/* Fail if the RTE has ORDINALITY - we don't implement that here. */
|
|
if (rte->funcordinality)
|
|
return NULL;
|
|
|
|
/* Fail if RTE isn't a single, simple FuncExpr */
|
|
if (list_length(rte->functions) != 1)
|
|
return NULL;
|
|
rtfunc = (RangeTblFunction *) linitial(rte->functions);
|
|
|
|
if (!IsA(rtfunc->funcexpr, FuncExpr))
|
|
return NULL;
|
|
fexpr = (FuncExpr *) rtfunc->funcexpr;
|
|
|
|
func_oid = fexpr->funcid;
|
|
|
|
/*
|
|
* The function must be declared to return a set, else inlining would
|
|
* change the results if the contained SELECT didn't return exactly one
|
|
* row.
|
|
*/
|
|
if (!fexpr->funcretset)
|
|
return NULL;
|
|
|
|
/*
|
|
* Refuse to inline if the arguments contain any volatile functions or
|
|
* sub-selects. Volatile functions are rejected because inlining may
|
|
* result in the arguments being evaluated multiple times, risking a
|
|
* change in behavior. Sub-selects are rejected partly for implementation
|
|
* reasons (pushing them down another level might change their behavior)
|
|
* and partly because they're likely to be expensive and so multiple
|
|
* evaluation would be bad.
|
|
*/
|
|
if (contain_volatile_functions((Node *) fexpr->args) ||
|
|
contain_subplans((Node *) fexpr->args))
|
|
return NULL;
|
|
|
|
/* Check permission to call function (fail later, if not) */
|
|
if (pg_proc_aclcheck(func_oid, GetUserId(), ACL_EXECUTE) != ACLCHECK_OK)
|
|
return NULL;
|
|
|
|
/* Check whether a plugin wants to hook function entry/exit */
|
|
if (FmgrHookIsNeeded(func_oid))
|
|
return NULL;
|
|
|
|
/*
|
|
* OK, let's take a look at the function's pg_proc entry.
|
|
*/
|
|
func_tuple = SearchSysCache1(PROCOID, ObjectIdGetDatum(func_oid));
|
|
if (!HeapTupleIsValid(func_tuple))
|
|
elog(ERROR, "cache lookup failed for function %u", func_oid);
|
|
funcform = (Form_pg_proc) GETSTRUCT(func_tuple);
|
|
|
|
/*
|
|
* Forget it if the function is not SQL-language or has other showstopper
|
|
* properties. In particular it mustn't be declared STRICT, since we
|
|
* couldn't enforce that. It also mustn't be VOLATILE, because that is
|
|
* supposed to cause it to be executed with its own snapshot, rather than
|
|
* sharing the snapshot of the calling query. We also disallow returning
|
|
* SETOF VOID, because inlining would result in exposing the actual result
|
|
* of the function's last SELECT, which should not happen in that case.
|
|
* (Rechecking prokind, proretset, and pronargs is just paranoia.)
|
|
*/
|
|
if (funcform->prolang != SQLlanguageId ||
|
|
funcform->prokind != PROKIND_FUNCTION ||
|
|
funcform->proisstrict ||
|
|
funcform->provolatile == PROVOLATILE_VOLATILE ||
|
|
funcform->prorettype == VOIDOID ||
|
|
funcform->prosecdef ||
|
|
!funcform->proretset ||
|
|
list_length(fexpr->args) != funcform->pronargs ||
|
|
!heap_attisnull(func_tuple, Anum_pg_proc_proconfig, NULL))
|
|
{
|
|
ReleaseSysCache(func_tuple);
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Make a temporary memory context, so that we don't leak all the stuff
|
|
* that parsing might create.
|
|
*/
|
|
mycxt = AllocSetContextCreate(CurrentMemoryContext,
|
|
"inline_set_returning_function",
|
|
ALLOCSET_DEFAULT_SIZES);
|
|
oldcxt = MemoryContextSwitchTo(mycxt);
|
|
|
|
/* Fetch the function body */
|
|
tmp = SysCacheGetAttr(PROCOID,
|
|
func_tuple,
|
|
Anum_pg_proc_prosrc,
|
|
&isNull);
|
|
if (isNull)
|
|
elog(ERROR, "null prosrc for function %u", func_oid);
|
|
src = TextDatumGetCString(tmp);
|
|
|
|
/*
|
|
* Setup error traceback support for ereport(). This is so that we can
|
|
* finger the function that bad information came from.
|
|
*/
|
|
callback_arg.proname = NameStr(funcform->proname);
|
|
callback_arg.prosrc = src;
|
|
|
|
sqlerrcontext.callback = sql_inline_error_callback;
|
|
sqlerrcontext.arg = (void *) &callback_arg;
|
|
sqlerrcontext.previous = error_context_stack;
|
|
error_context_stack = &sqlerrcontext;
|
|
|
|
/*
|
|
* Set up to handle parameters while parsing the function body. We can
|
|
* use the FuncExpr just created as the input for
|
|
* prepare_sql_fn_parse_info.
|
|
*/
|
|
pinfo = prepare_sql_fn_parse_info(func_tuple,
|
|
(Node *) fexpr,
|
|
fexpr->inputcollid);
|
|
|
|
/*
|
|
* Also resolve the actual function result tupdesc, if composite. If the
|
|
* function is just declared to return RECORD, dig the info out of the AS
|
|
* clause.
|
|
*/
|
|
functypclass = get_expr_result_type((Node *) fexpr, NULL, &rettupdesc);
|
|
if (functypclass == TYPEFUNC_RECORD)
|
|
rettupdesc = BuildDescFromLists(rtfunc->funccolnames,
|
|
rtfunc->funccoltypes,
|
|
rtfunc->funccoltypmods,
|
|
rtfunc->funccolcollations);
|
|
|
|
/*
|
|
* Parse, analyze, and rewrite (unlike inline_function(), we can't skip
|
|
* rewriting here). We can fail as soon as we find more than one query,
|
|
* though.
|
|
*/
|
|
raw_parsetree_list = pg_parse_query(src);
|
|
if (list_length(raw_parsetree_list) != 1)
|
|
goto fail;
|
|
|
|
querytree_list = pg_analyze_and_rewrite_params(linitial(raw_parsetree_list),
|
|
src,
|
|
(ParserSetupHook) sql_fn_parser_setup,
|
|
pinfo, NULL);
|
|
if (list_length(querytree_list) != 1)
|
|
goto fail;
|
|
querytree = linitial(querytree_list);
|
|
|
|
/*
|
|
* The single command must be a plain SELECT.
|
|
*/
|
|
if (!IsA(querytree, Query) ||
|
|
querytree->commandType != CMD_SELECT)
|
|
goto fail;
|
|
|
|
/*
|
|
* Make sure the function (still) returns what it's declared to. This
|
|
* will raise an error if wrong, but that's okay since the function would
|
|
* fail at runtime anyway. Note that check_sql_fn_retval will also insert
|
|
* coercions if needed to make the tlist expression(s) match the declared
|
|
* type of the function. We also ask it to insert dummy NULL columns for
|
|
* any dropped columns in rettupdesc, so that the elements of the modified
|
|
* tlist match up to the attribute numbers.
|
|
*
|
|
* If the function returns a composite type, don't inline unless the check
|
|
* shows it's returning a whole tuple result; otherwise what it's
|
|
* returning is a single composite column which is not what we need.
|
|
*/
|
|
if (!check_sql_fn_retval(querytree_list,
|
|
fexpr->funcresulttype, rettupdesc,
|
|
true, NULL) &&
|
|
(functypclass == TYPEFUNC_COMPOSITE ||
|
|
functypclass == TYPEFUNC_COMPOSITE_DOMAIN ||
|
|
functypclass == TYPEFUNC_RECORD))
|
|
goto fail; /* reject not-whole-tuple-result cases */
|
|
|
|
/*
|
|
* check_sql_fn_retval might've inserted a projection step, but that's
|
|
* fine; just make sure we use the upper Query.
|
|
*/
|
|
querytree = linitial(querytree_list);
|
|
|
|
/*
|
|
* Looks good --- substitute parameters into the query.
|
|
*/
|
|
querytree = substitute_actual_srf_parameters(querytree,
|
|
funcform->pronargs,
|
|
fexpr->args);
|
|
|
|
/*
|
|
* Copy the modified query out of the temporary memory context, and clean
|
|
* up.
|
|
*/
|
|
MemoryContextSwitchTo(oldcxt);
|
|
|
|
querytree = copyObject(querytree);
|
|
|
|
MemoryContextDelete(mycxt);
|
|
error_context_stack = sqlerrcontext.previous;
|
|
ReleaseSysCache(func_tuple);
|
|
|
|
/*
|
|
* We don't have to fix collations here because the upper query is already
|
|
* parsed, ie, the collations in the RTE are what count.
|
|
*/
|
|
|
|
/*
|
|
* Since there is now no trace of the function in the plan tree, we must
|
|
* explicitly record the plan's dependency on the function.
|
|
*/
|
|
record_plan_function_dependency(root, func_oid);
|
|
|
|
return querytree;
|
|
|
|
/* Here if func is not inlinable: release temp memory and return NULL */
|
|
fail:
|
|
MemoryContextSwitchTo(oldcxt);
|
|
MemoryContextDelete(mycxt);
|
|
error_context_stack = sqlerrcontext.previous;
|
|
ReleaseSysCache(func_tuple);
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Replace Param nodes by appropriate actual parameters
|
|
*
|
|
* This is just enough different from substitute_actual_parameters()
|
|
* that it needs its own code.
|
|
*/
|
|
static Query *
|
|
substitute_actual_srf_parameters(Query *expr, int nargs, List *args)
|
|
{
|
|
substitute_actual_srf_parameters_context context;
|
|
|
|
context.nargs = nargs;
|
|
context.args = args;
|
|
context.sublevels_up = 1;
|
|
|
|
return query_tree_mutator(expr,
|
|
substitute_actual_srf_parameters_mutator,
|
|
&context,
|
|
0);
|
|
}
|
|
|
|
static Node *
|
|
substitute_actual_srf_parameters_mutator(Node *node,
|
|
substitute_actual_srf_parameters_context *context)
|
|
{
|
|
Node *result;
|
|
|
|
if (node == NULL)
|
|
return NULL;
|
|
if (IsA(node, Query))
|
|
{
|
|
context->sublevels_up++;
|
|
result = (Node *) query_tree_mutator((Query *) node,
|
|
substitute_actual_srf_parameters_mutator,
|
|
(void *) context,
|
|
0);
|
|
context->sublevels_up--;
|
|
return result;
|
|
}
|
|
if (IsA(node, Param))
|
|
{
|
|
Param *param = (Param *) node;
|
|
|
|
if (param->paramkind == PARAM_EXTERN)
|
|
{
|
|
if (param->paramid <= 0 || param->paramid > context->nargs)
|
|
elog(ERROR, "invalid paramid: %d", param->paramid);
|
|
|
|
/*
|
|
* Since the parameter is being inserted into a subquery, we must
|
|
* adjust levels.
|
|
*/
|
|
result = copyObject(list_nth(context->args, param->paramid - 1));
|
|
IncrementVarSublevelsUp(result, context->sublevels_up, 0);
|
|
return result;
|
|
}
|
|
}
|
|
return expression_tree_mutator(node,
|
|
substitute_actual_srf_parameters_mutator,
|
|
(void *) context);
|
|
}
|