{
Oid *argtypes; /* resolved types of arguments */
Oid rettype; /* actual return type */
- int typlen; /* length of the return type */
+ int16 typlen; /* length of the return type */
bool typbyval; /* true if return type is pass by value */
bool returnsTuple; /* true if returning whole tuple result */
bool shutdown_reg; /* true if registered shutdown callback */
Oid foid = finfo->fn_oid;
Oid rettype;
HeapTuple procedureTuple;
- HeapTuple typeTuple;
Form_pg_proc procedureStruct;
- Form_pg_type typeStruct;
SQLFunctionCachePtr fcache;
Oid *argOidVect;
- bool haspolyarg;
char *src;
int nargs;
List *queryTree_list;
fcache->rettype = rettype;
+ /* Fetch the typlen and byval info for the result type */
+ get_typlenbyval(rettype, &fcache->typlen, &fcache->typbyval);
+
/* Remember if function is STABLE/IMMUTABLE */
fcache->readonly_func =
(procedureStruct->provolatile != PROVOLATILE_VOLATILE);
- /* Now look up the actual result type */
- typeTuple = SearchSysCache(TYPEOID,
- ObjectIdGetDatum(rettype),
- 0, 0, 0);
- if (!HeapTupleIsValid(typeTuple))
- elog(ERROR, "cache lookup failed for type %u", rettype);
- typeStruct = (Form_pg_type) GETSTRUCT(typeTuple);
-
- /*
- * get the type length and by-value flag from the type tuple; also do
- * a preliminary check for returnsTuple (this may prove inaccurate,
- * see below).
- */
- fcache->typlen = typeStruct->typlen;
- fcache->typbyval = typeStruct->typbyval;
- fcache->returnsTuple = (typeStruct->typtype == 'c' ||
- rettype == RECORDOID);
-
/*
- * Parse and rewrite the queries. We need the argument type info to
- * pass to the parser.
+ * We need the actual argument types to pass to the parser.
*/
nargs = procedureStruct->pronargs;
- haspolyarg = false;
-
if (nargs > 0)
{
int argnum;
errmsg("could not determine actual type of argument declared %s",
format_type_be(argOidVect[argnum]))));
argOidVect[argnum] = argtype;
- haspolyarg = true;
}
}
}
argOidVect = NULL;
fcache->argtypes = argOidVect;
+ /*
+ * Parse and rewrite the queries in the function text.
+ */
tmp = SysCacheGetAttr(PROCOID,
procedureTuple,
Anum_pg_proc_prosrc,
queryTree_list = pg_parse_and_rewrite(src, argOidVect, nargs);
/*
- * If the function has any arguments declared as polymorphic types,
- * then it wasn't type-checked at definition time; must do so now.
+ * Check that the function returns the type it claims to. Although
+ * in simple cases this was already done when the function was defined,
+ * we have to recheck because database objects used in the function's
+ * queries might have changed type. We'd have to do it anyway if the
+ * function had any polymorphic arguments.
*
- * Also, force a type-check if the declared return type is a rowtype; we
- * need to find out whether we are actually returning the whole tuple
- * result, or just regurgitating a rowtype expression result. In the
+ * Note: we set fcache->returnsTuple according to whether we are
+ * returning the whole tuple result or just a single column. In the
* latter case we clear returnsTuple because we need not act different
- * from the scalar result case.
+ * from the scalar result case, even if it's a rowtype column.
*
- * In the returnsTuple case, check_sql_fn_retval will also construct
- * a JunkFilter we can use to coerce the returned rowtype to the desired
+ * In the returnsTuple case, check_sql_fn_retval will also construct a
+ * JunkFilter we can use to coerce the returned rowtype to the desired
* form.
*/
- if (haspolyarg || fcache->returnsTuple)
- fcache->returnsTuple = check_sql_fn_retval(rettype,
- get_typtype(rettype),
- queryTree_list,
- &fcache->junkFilter);
+ fcache->returnsTuple = check_sql_fn_retval(rettype,
+ get_typtype(rettype),
+ queryTree_list,
+ &fcache->junkFilter);
/* Finally, plan the queries */
fcache->func_state = init_execution_state(queryTree_list,
pfree(src);
- ReleaseSysCache(typeTuple);
ReleaseSysCache(procedureTuple);
finfo->fn_extra = (void *) fcache;
* the final query in the function. We do some ad-hoc type checking here
* to be sure that the user is returning the type he claims.
*
- * This is normally applied during function definition, but in the case
- * of a function with polymorphic arguments, we instead apply it during
- * function execution startup. The rettype is then the actual resolved
- * output type of the function, rather than the declared type. (Therefore,
- * we should never see ANYARRAY or ANYELEMENT as rettype.)
+ * For a polymorphic function the passed rettype must be the actual resolved
+ * output type of the function; we should never see ANYARRAY or ANYELEMENT
+ * as rettype. (This means we can't check the type during function definition
+ * of a polymorphic function.)
*
* The return value is true if the function returns the entire tuple result
* of its final SELECT, and false otherwise. Note that because we allow
#include "postgres.h"
+#include "catalog/pg_aggregate.h"
#include "catalog/pg_language.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
#include "optimizer/var.h"
#include "parser/analyze.h"
#include "parser/parse_clause.h"
+#include "parser/parse_coerce.h"
#include "parser/parse_expr.h"
#include "tcop/tcopprot.h"
#include "utils/acl.h"
typedef struct
{
List *active_fns;
+ Node *case_val;
bool estimate;
} eval_const_expressions_context;
} substitute_actual_parameters_context;
static bool contain_agg_clause_walker(Node *node, void *context);
-static bool contain_distinct_agg_clause_walker(Node *node, void *context);
-static bool count_agg_clause_walker(Node *node, int *count);
+static bool count_agg_clauses_walker(Node *node, AggClauseCounts *counts);
static bool expression_returns_set_walker(Node *node, void *context);
static bool contain_subplans_walker(Node *node, void *context);
static bool contain_mutable_functions_walker(Node *node, void *context);
}
/*
- * contain_distinct_agg_clause
- * Recursively search for DISTINCT Aggref nodes within a clause.
+ * count_agg_clauses
+ * Recursively count the Aggref nodes in an expression tree.
+ *
+ * Note: this also checks for nested aggregates, which are an error.
*
- * Returns true if any DISTINCT aggregate found.
+ * We not only count the nodes, but attempt to estimate the total space
+ * needed for their transition state values if all are evaluated in parallel
+ * (as would be done in a HashAgg plan). See AggClauseCounts for the exact
+ * set of statistics returned.
+ *
+ * NOTE that the counts are ADDED to those already in *counts ... so the
+ * caller is responsible for zeroing the struct initially.
*
* This does not descend into subqueries, and so should be used only after
* reduction of sublinks to subplans, or in contexts where it's known there
* are no subqueries. There mustn't be outer-aggregate references either.
*/
-bool
-contain_distinct_agg_clause(Node *clause)
+void
+count_agg_clauses(Node *clause, AggClauseCounts *counts)
{
- return contain_distinct_agg_clause_walker(clause, NULL);
+ /* no setup needed */
+ count_agg_clauses_walker(clause, counts);
}
static bool
-contain_distinct_agg_clause_walker(Node *node, void *context)
+count_agg_clauses_walker(Node *node, AggClauseCounts *counts)
{
if (node == NULL)
return false;
if (IsA(node, Aggref))
{
- Assert(((Aggref *) node)->agglevelsup == 0);
- if (((Aggref *) node)->aggdistinct)
- return true; /* abort the tree traversal and return
- * true */
- }
- Assert(!IsA(node, SubLink));
- return expression_tree_walker(node, contain_distinct_agg_clause_walker, context);
-}
+ Aggref *aggref = (Aggref *) node;
+ Oid inputType;
+ HeapTuple aggTuple;
+ Form_pg_aggregate aggform;
+ Oid aggtranstype;
+
+ Assert(aggref->agglevelsup == 0);
+ counts->numAggs++;
+ if (aggref->aggdistinct)
+ counts->numDistinctAggs++;
+
+ inputType = exprType((Node *) aggref->target);
+
+ /* fetch aggregate transition datatype from pg_aggregate */
+ aggTuple = SearchSysCache(AGGFNOID,
+ ObjectIdGetDatum(aggref->aggfnoid),
+ 0, 0, 0);
+ if (!HeapTupleIsValid(aggTuple))
+ elog(ERROR, "cache lookup failed for aggregate %u",
+ aggref->aggfnoid);
+ aggform = (Form_pg_aggregate) GETSTRUCT(aggTuple);
+ aggtranstype = aggform->aggtranstype;
+ ReleaseSysCache(aggTuple);
+
+ /* resolve actual type of transition state, if polymorphic */
+ if (aggtranstype == ANYARRAYOID || aggtranstype == ANYELEMENTOID)
+ {
+ /* have to fetch the agg's declared input type... */
+ Oid agg_arg_types[FUNC_MAX_ARGS];
+ int agg_nargs;
+
+ (void) get_func_signature(aggref->aggfnoid,
+ agg_arg_types, &agg_nargs);
+ Assert(agg_nargs == 1);
+ aggtranstype = resolve_generic_type(aggtranstype,
+ inputType,
+ agg_arg_types[0]);
+ }
-/*
- * count_agg_clause
- * Recursively count the Aggref nodes in an expression tree.
- *
- * Note: this also checks for nested aggregates, which are an error.
- *
- * This does not descend into subqueries, and so should be used only after
- * reduction of sublinks to subplans, or in contexts where it's known there
- * are no subqueries. There mustn't be outer-aggregate references either.
- */
-int
-count_agg_clause(Node *clause)
-{
- int result = 0;
+ /*
+ * If the transition type is pass-by-value then it doesn't add
+ * anything to the required size of the hashtable. If it is
+ * pass-by-reference then we have to add the estimated size of
+ * the value itself, plus palloc overhead.
+ */
+ if (!get_typbyval(aggtranstype))
+ {
+ int32 aggtranstypmod;
+ int32 avgwidth;
- count_agg_clause_walker(clause, &result);
- return result;
-}
+ /*
+ * If transition state is of same type as input, assume it's the
+ * same typmod (same width) as well. This works for cases like
+ * MAX/MIN and is probably somewhat reasonable otherwise.
+ */
+ if (aggtranstype == inputType)
+ aggtranstypmod = exprTypmod((Node *) aggref->target);
+ else
+ aggtranstypmod = -1;
-static bool
-count_agg_clause_walker(Node *node, int *count)
-{
- if (node == NULL)
- return false;
- if (IsA(node, Aggref))
- {
- Assert(((Aggref *) node)->agglevelsup == 0);
- (*count)++;
+ avgwidth = get_typavgwidth(aggtranstype, aggtranstypmod);
+ avgwidth = MAXALIGN(avgwidth);
+
+ counts->transitionSpace += avgwidth + 2 * sizeof(void *);
+ }
/*
* Complain if the aggregate's argument contains any aggregates;
* nested agg functions are semantically nonsensical.
*/
- if (contain_agg_clause((Node *) ((Aggref *) node)->target))
+ if (contain_agg_clause((Node *) aggref->target))
ereport(ERROR,
(errcode(ERRCODE_GROUPING_ERROR),
errmsg("aggregate function calls may not be nested")));
return false;
}
Assert(!IsA(node, SubLink));
- return expression_tree_walker(node, count_agg_clause_walker,
- (void *) count);
+ return expression_tree_walker(node, count_agg_clauses_walker,
+ (void *) counts);
}
eval_const_expressions_context context;
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);
}
eval_const_expressions_context context;
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);
}
* If there are no non-FALSE alternatives, we simplify the entire
* CASE to the default result (ELSE result).
*
- * If we have a simple-form CASE with constant test expression and
- * one or more constant comparison expressions, we could run the
- * implied comparisons and potentially reduce those arms to constants.
- * This is not yet implemented, however. At present, the
- * CaseTestExpr placeholder will always act as a non-constant node
- * and prevent the comparison boolean expressions from being reduced
- * to Const nodes.
+ * 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.
*----------
*/
CaseExpr *caseexpr = (CaseExpr *) node;
CaseExpr *newcase;
+ Node *save_case_val;
Node *newarg;
List *newargs;
- Node *defresult;
- Const *const_input;
+ 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;
+ else
+ context->case_val = NULL;
+
/* Simplify the WHEN clauses */
newargs = NIL;
+ const_true_cond = false;
foreach(arg, caseexpr->args)
{
- /* Simplify this alternative's condition and result */
- CaseWhen *casewhen = (CaseWhen *)
- expression_tree_mutator((Node *) lfirst(arg),
- eval_const_expressions_mutator,
- (void *) context);
-
- Assert(IsA(casewhen, CaseWhen));
- if (casewhen->expr == NULL ||
- !IsA(casewhen->expr, Const))
- {
- newargs = lappend(newargs, casewhen);
- continue;
- }
- const_input = (Const *) casewhen->expr;
- if (const_input->constisnull ||
- !DatumGetBool(const_input->constvalue))
- continue; /* drop alternative with FALSE condition */
+ CaseWhen *oldcasewhen = (CaseWhen *) lfirst(arg);
+ Node *casecond;
+ Node *caseresult;
+
+ Assert(IsA(oldcasewhen, CaseWhen));
+
+ /* Simplify this alternative's test condition */
+ casecond =
+ eval_const_expressions_mutator((Node *) oldcasewhen->expr,
+ context);
/*
- * Found a TRUE condition. If it's the first (un-dropped)
- * alternative, the CASE reduces to just this alternative.
+ * If the test condition is constant FALSE (or NULL), then drop
+ * this WHEN clause completely, without processing the result.
*/
- if (newargs == NIL)
- return (Node *) casewhen->result;
+ if (casecond && IsA(casecond, Const))
+ {
+ Const *const_input = (Const *) casecond;
+
+ if (const_input->constisnull ||
+ !DatumGetBool(const_input->constvalue))
+ continue; /* drop alternative with FALSE condition */
+ /* 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;
+ newargs = lappend(newargs, newcasewhen);
+ continue;
+ }
+
/*
- * Otherwise, add it to the list, and drop all the rest.
+ * Found a TRUE condition, so none of the remaining alternatives
+ * can be reached. We treat the result as the default result.
*/
- newargs = lappend(newargs, casewhen);
+ defresult = caseresult;
break;
}
- /* Simplify the default result */
- defresult = eval_const_expressions_mutator((Node *) caseexpr->defresult,
- context);
+ /* Simplify the default result, unless we replaced it above */
+ if (!const_true_cond)
+ defresult =
+ eval_const_expressions_mutator((Node *) caseexpr->defresult,
+ context);
- /*
- * If no non-FALSE alternatives, CASE reduces to the default
- * result
- */
+ 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->defresult = (Expr *) defresult;
return (Node *) newcase;
}
+ if (IsA(node, 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);
+ }
if (IsA(node, ArrayExpr))
{
ArrayExpr *arrayexpr = (ArrayExpr *) node;
newargs = lappend(newargs, e);
}
+ /* If all the arguments were constant null, the result is just null */
+ if (newargs == NIL)
+ return (Node *) makeNullConst(coalesceexpr->coalescetype);
+
newcoalesce = makeNode(CoalesceExpr);
newcoalesce->coalescetype = coalesceexpr->coalescetype;
newcoalesce->args = newargs;
if (funcform->proretset)
return NULL;
+ /*
+ * Can't simplify if it returns RECORD, since it will be needing an
+ * expected tupdesc which we can't supply here.
+ */
+ if (funcform->prorettype == RECORDOID)
+ return NULL;
+
/*
* Check for constant inputs and especially constant-NULL inputs.
*/
eval_const_expressions_context *context)
{
Form_pg_proc funcform = (Form_pg_proc) GETSTRUCT(func_tuple);
- bool polymorphic = false;
Oid argtypes[FUNC_MAX_ARGS];
char *src;
Datum tmp;
if (argtypes[i] == ANYARRAYOID ||
argtypes[i] == ANYELEMENTOID)
{
- polymorphic = true;
argtypes[i] = exprType((Node *) list_nth(args, i));
}
}
- if (funcform->prorettype == ANYARRAYOID ||
- funcform->prorettype == ANYELEMENTOID)
- polymorphic = true;
-
/*
* Setup error traceback support for ereport(). This is so that we
* can finger the function that bad information came from.
newexpr = (Node *) ((TargetEntry *) linitial(querytree->targetList))->expr;
/*
- * If the function has any arguments declared as polymorphic types,
- * then it wasn't type-checked at definition time; must do so now.
- * (This will raise an error if wrong, but that's okay since the
- * function would fail at runtime anyway. 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.)
+ * 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 we do not try this until we have verified that
+ * no rewriting was needed; that's probably not important, but let's be
+ * careful.
*/
- if (polymorphic)
- (void) check_sql_fn_retval(result_type, get_typtype(result_type),
- querytree_list, NULL);
+ (void) check_sql_fn_retval(result_type, get_typtype(result_type),
+ querytree_list, NULL);
/*
* Additional validity checks on the expression. It mustn't return a
projects / users / bernd / postgres.git / commitdiff