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Support use of function argument names to identify which actual arguments

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match which function parameters.  The syntax uses AS, for example
	funcname(value AS arg1, anothervalue AS arg2)

Pavel Stehule
This commit is contained in:
Tom Lane
2009-10-08 02:39:25 +00:00
parent 2eda8dfb52
commit 717fa274d1
34 changed files with 1925 additions and 274 deletions
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17
src/backend/optimizer/plan/planner.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/plan/planner.c,v 1.256 2009/06/11 14:48:59 momjian Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/plan/planner.c,v 1.257 2009/10/08 02:39:21 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -526,7 +526,8 @@ preprocess_expression(PlannerInfo *root, Node *expr, int kind)
/*
* Simplify constant expressions.
*
* Note: one essential effect here is to insert the current actual values
* Note: an essential effect of this is to convert named-argument function
* calls to positional notation and insert the current actual values
* of any default arguments for functions. To ensure that happens, we
* *must* process all expressions here. Previous PG versions sometimes
* skipped const-simplification if it didn't seem worth the trouble, but
@ -2658,9 +2659,10 @@ get_column_info_for_window(PlannerInfo *root, WindowClause *wc, List *tlist,
* Currently, we disallow sublinks in standalone expressions, so there's no
* real "planning" involved here. (That might not always be true though.)
* What we must do is run eval_const_expressions to ensure that any function
* default arguments get inserted. The fact that constant subexpressions
* get simplified is a side-effect that is useful when the expression will
* get evaluated more than once. Also, we must fix operator function IDs.
* calls are converted to positional notation and function default arguments
* get inserted. The fact that constant subexpressions get simplified is a
* side-effect that is useful when the expression will get evaluated more than
* once. Also, we must fix operator function IDs.
*
* Note: this must not make any damaging changes to the passed-in expression
* tree. (It would actually be okay to apply fix_opfuncids to it, but since
@ -2672,7 +2674,10 @@ expression_planner(Expr *expr)
{
Node *result;
/* Insert default arguments and simplify constant subexprs */
/*
* Convert named-argument function calls, insert default arguments and
* simplify constant subexprs
*/
result = eval_const_expressions(NULL, (Node *) expr);
/* Fill in opfuncid values if missing */

326
src/backend/optimizer/util/clauses.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.278 2009/07/20 00:24:30 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.279 2009/10/08 02:39:21 tgl Exp $
*
* HISTORY
* AUTHOR DATE MAJOR EVENT
@ -95,11 +95,18 @@ static List *simplify_and_arguments(List *args,
static Expr *simplify_boolean_equality(Oid opno, List *args);
static Expr *simplify_function(Oid funcid,
Oid result_type, int32 result_typmod, List **args,
bool has_named_args,
bool allow_inline,
eval_const_expressions_context *context);
static List *reorder_function_arguments(List *args, Oid result_type,
HeapTuple func_tuple,
eval_const_expressions_context *context);
static List *add_function_defaults(List *args, Oid result_type,
HeapTuple func_tuple,
eval_const_expressions_context *context);
static List *fetch_function_defaults(HeapTuple func_tuple);
static void recheck_cast_function_args(List *args, Oid result_type,
HeapTuple func_tuple);
static Expr *evaluate_function(Oid funcid,
Oid result_type, int32 result_typmod, List *args,
HeapTuple func_tuple,
@ -2003,7 +2010,8 @@ rowtype_field_matches(Oid rowtypeid, int fieldnum,
* 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.
* default arguments will be expanded, and named-argument calls will be
* converted to positional notation. The executor won't handle either.
*--------------------
*/
Node *
@ -2113,17 +2121,26 @@ eval_const_expressions_mutator(Node *node,
{
FuncExpr *expr = (FuncExpr *) node;
List *args;
bool has_named_args;
Expr *simple;
FuncExpr *newexpr;
ListCell *lc;
/*
* Reduce constants in the FuncExpr'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.
* Reduce constants in the FuncExpr's arguments, and check to see
* if there are any named args.
*/
args = (List *) expression_tree_mutator((Node *) expr->args,
eval_const_expressions_mutator,
(void *) context);
args = NIL;
has_named_args = false;
foreach(lc, expr->args)
{
Node *arg = (Node *) lfirst(lc);
arg = eval_const_expressions_mutator(arg, context);
if (IsA(arg, NamedArgExpr))
has_named_args = true;
args = lappend(args, arg);
}
/*
* Code for op/func reduction is pretty bulky, so split it out as a
@ -2134,14 +2151,15 @@ eval_const_expressions_mutator(Node *node,
simple = simplify_function(expr->funcid,
expr->funcresulttype, exprTypmod(node),
&args,
true, context);
has_named_args, 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.
* arguments. Note that we have also converted the argument list
* to positional notation.
*/
newexpr = makeNode(FuncExpr);
newexpr->funcid = expr->funcid;
@ -2181,7 +2199,7 @@ eval_const_expressions_mutator(Node *node,
simple = simplify_function(expr->opfuncid,
expr->opresulttype, -1,
&args,
true, context);
false, true, context);
if (simple) /* successfully simplified it */
return (Node *) simple;
@ -2274,7 +2292,7 @@ eval_const_expressions_mutator(Node *node,
simple = simplify_function(expr->opfuncid,
expr->opresulttype, -1,
&args,
false, context);
false, false, context);
if (simple) /* successfully simplified it */
{
/*
@ -2466,7 +2484,7 @@ eval_const_expressions_mutator(Node *node,
simple = simplify_function(outfunc,
CSTRINGOID, -1,
&args,
true, context);
false, true, context);
if (simple) /* successfully simplified output fn */
{
/*
@ -2484,7 +2502,7 @@ eval_const_expressions_mutator(Node *node,
simple = simplify_function(infunc,
expr->resulttype, -1,
&args,
true, context);
false, true, context);
if (simple) /* successfully simplified input fn */
return (Node *) simple;
}
@ -3241,15 +3259,16 @@ simplify_boolean_equality(Oid opno, List *args)
* Returns a simplified expression if successful, or NULL if cannot
* simplify the function call.
*
* This function is also responsible for adding any default argument
* expressions onto the function argument list; which is a bit grotty,
* but it avoids an extra fetch of the function's pg_proc tuple. For this
* reason, the args list is pass-by-reference, and it may get modified
* even if simplification fails.
* 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 an extra fetch of the
* function's pg_proc tuple. For this reason, the args list is
* pass-by-reference, and it may get modified even if simplification fails.
*/
static Expr *
simplify_function(Oid funcid, Oid result_type, int32 result_typmod,
List **args,
bool has_named_args,
bool allow_inline,
eval_const_expressions_context *context)
{
@ -3270,8 +3289,14 @@ simplify_function(Oid funcid, Oid result_type, int32 result_typmod,
if (!HeapTupleIsValid(func_tuple))
elog(ERROR, "cache lookup failed for function %u", funcid);
/* While we have the tuple, check if we need to add defaults */
if (((Form_pg_proc) GETSTRUCT(func_tuple))->pronargs > list_length(*args))
/*
* While we have the tuple, reorder named arguments and add default
* arguments if needed.
*/
if (has_named_args)
*args = reorder_function_arguments(*args, result_type, func_tuple,
context);
else if (((Form_pg_proc) GETSTRUCT(func_tuple))->pronargs > list_length(*args))
*args = add_function_defaults(*args, result_type, func_tuple, context);
newexpr = evaluate_function(funcid, result_type, result_typmod, *args,
@ -3286,13 +3311,113 @@ simplify_function(Oid funcid, Oid result_type, int32 result_typmod,
return newexpr;
}
/*
* 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, Oid result_type, HeapTuple func_tuple,
eval_const_expressions_context *context)
{
Form_pg_proc funcform = (Form_pg_proc) GETSTRUCT(func_tuple);
int pronargs = funcform->pronargs;
int nargsprovided = list_length(args);
Node *argarray[FUNC_MAX_ARGS];
Bitmapset *defargnumbers;
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)
*/
defargnumbers = NULL;
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);
defargnumbers = bms_add_member(defargnumbers, i);
}
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]);
}
/* Recheck argument types and add casts if needed */
recheck_cast_function_args(args, result_type, func_tuple);
/*
* Lastly, we have to recursively simplify the defaults we just added
* (but don't recurse on the args passed in, as we already did those).
* This isn't merely an optimization, it's *necessary* since there could
* be functions with named or defaulted arguments down in there.
*
* Note that we do this last in hopes of simplifying any typecasts that
* were added by recheck_cast_function_args --- there shouldn't be any new
* casts added to the explicit arguments, but casts on the defaults are
* possible.
*/
if (defargnumbers != NULL)
{
i = 0;
foreach(lc, args)
{
if (bms_is_member(i, defargnumbers))
lfirst(lc) = eval_const_expressions_mutator((Node *) lfirst(lc),
context);
i++;
}
}
return args;
}
/*
* add_function_defaults: add missing function arguments from its 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 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, Oid result_type, HeapTuple func_tuple,
@ -3300,16 +3425,58 @@ add_function_defaults(List *args, Oid result_type, HeapTuple func_tuple,
{
Form_pg_proc funcform = (Form_pg_proc) GETSTRUCT(func_tuple);
int nargsprovided = list_length(args);
List *defaults;
int ndelete;
ListCell *lc;
/* 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");
while (ndelete-- > 0)
defaults = list_delete_first(defaults);
/* And form the combined argument list */
args = list_concat(args, defaults);
/* Recheck argument types and add casts if needed */
recheck_cast_function_args(args, result_type, func_tuple);
/*
* Lastly, we have to recursively simplify the defaults we just added
* (but don't recurse on the args passed in, as we already did those).
* This isn't merely an optimization, it's *necessary* since there could
* be functions with named or defaulted arguments down in there.
*
* Note that we do this last in hopes of simplifying any typecasts that
* were added by recheck_cast_function_args --- there shouldn't be any new
* casts added to the explicit arguments, but casts on the defaults are
* possible.
*/
foreach(lc, args)
{
if (nargsprovided-- > 0)
continue; /* skip original arg positions */
lfirst(lc) = eval_const_expressions_mutator((Node *) lfirst(lc),
context);
}
return args;
}
/*
* 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;
List *defaults;
int ndelete;
int nargs;
Oid actual_arg_types[FUNC_MAX_ARGS];
Oid declared_arg_types[FUNC_MAX_ARGS];
Oid rettype;
ListCell *lc;
/* The error cases here shouldn't happen, but check anyway */
proargdefaults = SysCacheGetAttr(PROCOID, func_tuple,
@ -3321,20 +3488,33 @@ add_function_defaults(List *args, Oid result_type, HeapTuple func_tuple,
defaults = (List *) stringToNode(str);
Assert(IsA(defaults, List));
pfree(str);
/* Delete any unused defaults from the list */
ndelete = nargsprovided + list_length(defaults) - funcform->pronargs;
if (ndelete < 0)
elog(ERROR, "not enough default arguments");
while (ndelete-- > 0)
defaults = list_delete_first(defaults);
/* And form the combined argument list */
args = list_concat(args, defaults);
Assert(list_length(args) == funcform->pronargs);
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.
*/
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;
/*
* The next part should be a no-op if there are no polymorphic arguments,
* but we do it anyway to be sure.
*/
if (list_length(args) > FUNC_MAX_ARGS)
elog(ERROR, "too many function arguments");
nargs = 0;
@ -3342,6 +3522,7 @@ add_function_defaults(List *args, Oid result_type, HeapTuple func_tuple,
{
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,
@ -3355,22 +3536,6 @@ add_function_defaults(List *args, Oid result_type, HeapTuple func_tuple,
/* perform any necessary typecasting of arguments */
make_fn_arguments(NULL, args, actual_arg_types, declared_arg_types);
/*
* Lastly, we have to recursively simplify the arguments we just added
* (but don't recurse on the ones passed in, as we already did those).
* This isn't merely an optimization, it's *necessary* since there could
* be functions with defaulted arguments down in there.
*/
foreach(lc, args)
{
if (nargsprovided-- > 0)
continue; /* skip original arg positions */
lfirst(lc) = eval_const_expressions_mutator((Node *) lfirst(lc),
context);
}
return args;
}
/*
@ -3916,6 +4081,7 @@ Query *
inline_set_returning_function(PlannerInfo *root, RangeTblEntry *rte)
{
FuncExpr *fexpr;
Oid func_oid;
HeapTuple func_tuple;
Form_pg_proc funcform;
Oid *argtypes;
@ -3944,6 +4110,7 @@ inline_set_returning_function(PlannerInfo *root, RangeTblEntry *rte)
fexpr = (FuncExpr *) rte->funcexpr;
if (fexpr == NULL || !IsA(fexpr, FuncExpr))
return NULL;
func_oid = fexpr->funcid;
/*
* The function must be declared to return a set, else inlining would
@ -3967,17 +4134,17 @@ inline_set_returning_function(PlannerInfo *root, RangeTblEntry *rte)
return NULL;
/* Check permission to call function (fail later, if not) */
if (pg_proc_aclcheck(fexpr->funcid, GetUserId(), ACL_EXECUTE) != ACLCHECK_OK)
if (pg_proc_aclcheck(func_oid, GetUserId(), ACL_EXECUTE) != ACLCHECK_OK)
return NULL;
/*
* OK, let's take a look at the function's pg_proc entry.
*/
func_tuple = SearchSysCache(PROCOID,
ObjectIdGetDatum(fexpr->funcid),
ObjectIdGetDatum(func_oid),
0, 0, 0);
if (!HeapTupleIsValid(func_tuple))
elog(ERROR, "cache lookup failed for function %u", fexpr->funcid);
elog(ERROR, "cache lookup failed for function %u", func_oid);
funcform = (Form_pg_proc) GETSTRUCT(func_tuple);
/*
@ -3985,16 +4152,15 @@ inline_set_returning_function(PlannerInfo *root, RangeTblEntry *rte)
* 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. (The nargs check is just
* paranoia, ditto rechecking proretset.)
* sharing the snapshot of the calling query. (Rechecking proretset is
* just paranoia.)
*/
if (funcform->prolang != SQLlanguageId ||
funcform->proisstrict ||
funcform->provolatile == PROVOLATILE_VOLATILE ||
funcform->prosecdef ||
!funcform->proretset ||
!heap_attisnull(func_tuple, Anum_pg_proc_proconfig) ||
funcform->pronargs != list_length(fexpr->args))
!heap_attisnull(func_tuple, Anum_pg_proc_proconfig))
{
ReleaseSysCache(func_tuple);
return NULL;
@ -4020,6 +4186,24 @@ inline_set_returning_function(PlannerInfo *root, RangeTblEntry *rte)
ALLOCSET_DEFAULT_MAXSIZE);
oldcxt = MemoryContextSwitchTo(mycxt);
/*
* Run eval_const_expressions on the function call. This is necessary
* to ensure that named-argument notation is converted to positional
* notation and any default arguments are inserted. It's a bit of
* overkill for the arguments, since they'll get processed again later,
* but no harm will be done.
*/
fexpr = (FuncExpr *) eval_const_expressions(root, (Node *) fexpr);
/* It should still be a call of the same function, but let's check */
if (!IsA(fexpr, FuncExpr) ||
fexpr->funcid != func_oid)
goto fail;
/* Arg list length should now match the function */
if (list_length(fexpr->args) != funcform->pronargs)
goto fail;
/* Check for polymorphic arguments, and substitute actual arg types */
argtypes = (Oid *) palloc(funcform->pronargs * sizeof(Oid));
memcpy(argtypes, funcform->proargtypes.values,
@ -4038,7 +4222,7 @@ inline_set_returning_function(PlannerInfo *root, RangeTblEntry *rte)
Anum_pg_proc_prosrc,
&isNull);
if (isNull)
elog(ERROR, "null prosrc for function %u", fexpr->funcid);
elog(ERROR, "null prosrc for function %u", func_oid);
src = TextDatumGetCString(tmp);
/*
@ -4076,7 +4260,7 @@ inline_set_returning_function(PlannerInfo *root, RangeTblEntry *rte)
* 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(fexpr->funcid, fexpr->funcresulttype,
if (!check_sql_fn_retval(func_oid, fexpr->funcresulttype,
querytree_list,
true, NULL) &&
(get_typtype(fexpr->funcresulttype) == TYPTYPE_COMPOSITE ||
@ -4116,7 +4300,7 @@ inline_set_returning_function(PlannerInfo *root, RangeTblEntry *rte)
* 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->glob, fexpr->funcid);
record_plan_function_dependency(root->glob, func_oid);
return querytree;