+ endterm="sql-createfunction-title"> command links the SQL function
+ to the C source function in one of two ways. If the SQL function
+ has the same name as the C source function the first form of the
+ statement is used. The string argument in the AS clause is the
+ full pathname of the file that contains the dynamically loadable
+ compiled object. If the name of C function is different from the
+ name of the SQL function, then the second form is used. In this
+ form the AS clause takes two string arguments, the first is the
+ full pathname of the dynamically loadable object file, and the
+ second is the link symbol that the dynamic loader should search
+ for. This link symbol is just the function name in the C source
+ code.
+
+ After it is used for the first time, a dynamically loaded, user
+ function is retained in memory, and future calls to the function
+ only incur the small overhead of a symbol table lookup.
- The string which specifies the object file (the string in the AS clause)
- should be the full path
- of the object code file for the function, bracketed by quotation
- marks. (
Postgres will not compile a
- function automatically; it must
- be compiled before it is used in a CREATE FUNCTION
- command. See below for additional information.)
+ The string which specifies the object file (the string in the AS
+ clause) should be the full path of the object
+ code file for the function, bracketed by quotation marks. If a
+ link symbol is used in the AS clause, the link symbol should also be
+ bracketed by single quotation marks, and should be exactly the
+ same as the name of function in the C source code. On UNIX systems
+ the command nm will print all of the link
+ symbols in a dynamically loadable object.
+ (
Postgres will not compile a function
+ automatically; it must be compiled before it is used in a CREATE
+ FUNCTION command. See below for additional information.)
Name Space Conflicts
- CREATE FUNCTION can decouple a C language
- function name from the name of the entry point. This is now the
- preferred technique to accomplish function overloading.
+ As of
Postgres v6.6, the alternative
+ form of the AS clause for the SQL CREATE
+ FUNCTION command described in
+ linkend="sql-createfunction-title" endterm="sql-createfunction-title">
+ decouples the SQL function name from the function name in the C
+ source code. This is now the preferred technique to accomplish
+ function overloading.
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/commands/define.c,v 1.34 1999/07/17 20:16:52 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/commands/define.c,v 1.35 1999/09/28 04:34:40 momjian Exp $
*
* DESCRIPTION
* The "DefineFoo" routines take the parse tree and pick out the
}
+/*
+ * For a dynamically linked C language object, the form of the clause is
+ *
+ * AS [, ]
+ *
+ * In all other cases
+ *
+ * AS
+ *
+ */
static void
-interpret_AS_clause(const char *languageName, const char *as,
+interpret_AS_clause(const char *languageName, const List *as,
char **prosrc_str_p, char **probin_str_p)
{
+ Assert(as != NIL);
if (strcmp(languageName, "C") == 0)
{
- /* For "C" language, store the given string in probin */
- *prosrc_str_p = "-";
- *probin_str_p = (char *) as;
+
+ /*
+ * For "C" language, store the file name in probin and, when
+ * given, the link symbol name in prosrc.
+ */
+ *probin_str_p = strVal(lfirst(as));
+ if (lnext(as) == NULL)
+ *prosrc_str_p = "-";
+ else
+ *prosrc_str_p = strVal(lsecond(as));
}
else
{
- /* Everything else wants the given string in prosrc */
- *prosrc_str_p = (char *) as;
+ /* Everything else wants the given string in prosrc. */
+ *prosrc_str_p = strVal(lfirst(as));
*probin_str_p = "-";
+
+ if (lnext(as) != NULL)
+ elog(ERROR, "CREATE FUNCTION: parse error in 'AS %s, %s'.",
+ strVal(lfirst(as)), strVal(lsecond(as)));
}
}
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.99 1999/09/23 17:02:46 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.100 1999/09/28 04:34:44 momjian Exp $
*
* HISTORY
* AUTHOR DATE MAJOR EVENT
%type stmtblock, stmtmulti,
result, relation_name_list, OptTableElementList,
OptInherit, definition,
- opt_with, func_args, func_args_list,
+ opt_with, func_args, func_args_list, func_as,
oper_argtypes, RuleActionList, RuleActionBlock, RuleActionMulti,
opt_column_list, columnList, opt_va_list, va_list,
sort_clause, sortby_list, index_params, index_list, name_list,
*****************************************************************************/
ProcedureStmt: CREATE FUNCTION func_name func_args
- RETURNS func_return opt_with AS Sconst LANGUAGE Sconst
+ RETURNS func_return opt_with AS func_as LANGUAGE Sconst
{
ProcedureStmt *n = makeNode(ProcedureStmt);
n->funcname = $3;
{ $$ = lappend($1,makeString($3)); }
;
+func_as: Sconst
+ { $$ = lcons(makeString($1),NIL); }
+ | Sconst ',' Sconst
+ { $$ = lappend(lcons(makeString($1),NIL), makeString($3)); }
+ ;
+
func_return: set_opt TypeId
{
TypeName *n = makeNode(TypeName);
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/utils/fmgr/dfmgr.c,v 1.32 1999/09/18 19:08:01 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/utils/fmgr/dfmgr.c,v 1.33 1999/09/28 04:34:46 momjian Exp $
*
*-------------------------------------------------------------------------
*/
HeapTuple procedureTuple;
Form_pg_proc procedureStruct;
char *proname,
- *probinstring;
+ *probinstring,
+ *prosrcstring,
+ *linksymbol;
Datum probinattr;
+ Datum prosrcattr;
func_ptr user_fn;
Relation rel;
bool isnull;
heap_close(rel, AccessShareLock);
- user_fn = handle_load(probinstring, proname);
+ prosrcattr = heap_getattr(procedureTuple,
+ Anum_pg_proc_prosrc,
+ RelationGetDescr(rel), &isnull);
+
+ if (isnull)
+ { /* Use the proname for the link symbol */
+ linksymbol = proname;
+ }
+ else if (!PointerIsValid(prosrcattr))
+ { /* pg_proc must be messed up! */
+ heap_close(rel);
+ elog(ERROR, "fmgr: Could not extract prosrc for %u from %s",
+ procedureId, ProcedureRelationName);
+ return (func_ptr) NULL;
+ }
+ else
+ { /* The text in prosrcattr is either "-" or
+ * a link symbol */
+ prosrcstring = textout((struct varlena *) prosrcattr);
+ if (strcmp(prosrcstring, "-") == 0)
+ linksymbol = proname;
+ else
+ linksymbol = prosrcstring;
+ }
+
+ user_fn = handle_load(probinstring, linksymbol);
pfree(probinstring);
*
* Copyright (c) 1994, Regents of the University of California
*
- * $Id: psqlHelp.h,v 1.75 1999/09/27 20:27:20 momjian Exp $
+ * $Id: psqlHelp.h,v 1.76 1999/09/28 04:34:48 momjian Exp $
*
*-------------------------------------------------------------------------
*/
"create a user-defined function",
"\
\tCREATE FUNCTION function_name ([type1, ...typeN]) RETURNS return_type\n\
-\tAS 'object_filename'|'sql-queries'|'builtin_function_name'\n\
-\tLANGUAGE 'c'|'sql'|'internal';"},
+\tAS 'sql-queries'|'builtin_function_name'|'object_filename'\n\
+\tLANGUAGE 'sql'|'internal'|'c';\n\
+\n\
+OR\n\
+\n\
+\tCREATE FUNCTION function_name ([type1, ...typeN]) RETURNS return_type\n\
+\tAS 'object_filename', 'link_symbol'\n\
+\tLANGUAGE 'c';"},
{"create index",
"construct an index",
"\
*
* Copyright (c) 1994, Regents of the University of California
*
- * $Id: parsenodes.h,v 1.79 1999/09/23 17:03:22 momjian Exp $
+ * $Id: parsenodes.h,v 1.80 1999/09/28 04:34:50 momjian Exp $
*
*-------------------------------------------------------------------------
*/
/* internal to planner */
List *base_rel_list; /* list of base-relation RelOptInfos */
List *join_rel_list; /* list of join-relation RelOptInfos */
- List *query_pathkeys; /* pathkeys for query_planner()'s result */
+ List *query_pathkeys; /* pathkeys for query_planner()'s result */
} Query;
Node *returnType; /* the return type (as a string or a
* TypeName (ie.setof) */
List *withClause; /* a list of ParamString */
- char *as; /* the SQL statement or filename */
+ List *as; /* the SQL statement or filename */
char *language; /* C or SQL */
} ProcedureStmt;
{
NodeTag type;
char *name; /* column name or NULL */
- List *indirection; /* subscripts for destination column, or NIL */
- Node *val; /* the value expression to compute or assign */
+ List *indirection; /* subscripts for destination column, or
+ * NIL */
+ Node *val; /* the value expression to compute or
+ * assign */
} ResTarget;
/*
typedef struct SortClause
{
NodeTag type;
- Index tleSortGroupRef; /* reference into targetlist */
+ Index tleSortGroupRef;/* reference into targetlist */
Oid sortop; /* the sort operator to use */
} SortClause;
%type opt_analyze opt_va_list va_list ExplainStmt index_params
%type index_list func_index index_elem opt_type opt_class access_method_clause
%type index_opt_unique IndexStmt set_opt func_return def_rest
-%type func_args_list func_args opt_with ProcedureStmt def_arg
+%type func_as func_args_list func_args opt_with ProcedureStmt def_arg
%type def_elem def_list definition def_name def_type DefineStmt
%type opt_instead event event_object RuleActionList,
%type RuleActionBlock RuleActionMulti join_list
* [, iscachable])
* [arg is ( { , })]
* as
+ * [, ]
*
*****************************************************************************/
ProcedureStmt: CREATE FUNCTION func_name func_args
- RETURNS func_return opt_with AS Sconst LANGUAGE Sconst
+ RETURNS func_return opt_with AS func_as LANGUAGE Sconst
{
$$ = cat2_str(cat5_str(cat5_str(make1_str("create function"), $3, $4, make1_str("returns"), $6), $7, make1_str("as"), $9, make1_str("language")), $11);
}
{ $$ = cat3_str($1, make1_str(","), $3); }
;
+func_as: Sconst
+ { $$ = $1; }
+ | Sconst ',' Sconst
+ { $$ = cat3_str($1, make1_str(","), $3); }
+ ;
+
func_return: set_opt TypeId
{
$$ = cat2_str($1, $2);
-
-
-
70,0,230,40" HREF="backend_dirs.html#main">-
70,80,230,120" HREF="backend_dirs.html#postmaster">-
30,40,490,80" HREF="backend_dirs.html#libpq">-
70,160,230,200" HREF="backend_dirs.html#tcop">-
30,160,490,200" HREF="backend_dirs.html#tcop">-
70,260,230,300" HREF="backend_dirs.html#parser">-
70,340,230,380" HREF="backend_dirs.html#tcop">-
70,420,230,460" HREF="backend_dirs.html#optimizer">-
70,400,230,540" HREF="backend_dirs.html#optimizer/plan">-
70,580,230,620" HREF="backend_dirs.html#executor">-
30,340,490,380" HREF="backend_dirs.html#commands">-
0,690,160,740" HREF="backend_dirs.html#utils">-
10,690,370,730" HREF="backend_dirs.html#catalog">-
20,690,590,740" HREF="backend_dirs.html#storage">-
00,770,270,820" HREF="backend_dirs.html#access">-
30,770,490,820" HREF="backend_dirs.html#nodes">-
10,860,170,900" HREF="backend_dirs.html#bootstrap">+
125,35,245,65" HREF="backend_dirs.html#main">+
125,100,245,125" HREF="backend_dirs.html#postmaster">+
25,65,450,95" HREF="backend_dirs.html#libpq">+
125,160,245,190" HREF="backend_dirs.html#tcop">+
25,160,450,190" HREF="backend_dirs.html#tcop">+
125,240,245,265" HREF="backend_dirs.html#parser">+
125,300,250,330" HREF="backend_dirs.html#tcop">+
125,360,250,390" HREF="backend_dirs.html#optimizer">+
125,425,245,455" HREF="backend_dirs.html#optimizer/plan">+
125,490,245,515" HREF="backend_dirs.html#executor">+
25,300,450,330" HREF="backend_dirs.html#commands">+
75,575,195,605" HREF="backend_dirs.html#utils">+
35,575,360,605" HREF="backend_dirs.html#catalog">+
05,575,525,605" HREF="backend_dirs.html#storage">+
55,635,275,665" HREF="backend_dirs.html#access">+
25,635,450,665" HREF="backend_dirs.html#nodes">+
75,705,200,730" HREF="backend_dirs.html#bootstrap">
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