Index: contrib/dblink/dblink.c
===================================================================
RCS file: /opt/src/cvs/pgsql/contrib/dblink/dblink.c,v
retrieving revision 1.77
diff -c -r1.77 dblink.c
*** contrib/dblink/dblink.c	1 Jan 2009 17:23:31 -0000	1.77
--- contrib/dblink/dblink.c	3 Jan 2009 21:25:34 -0000
***************
*** 46,51 ****
--- 46,52 ----
  #include "catalog/pg_type.h"
  #include "executor/executor.h"
  #include "executor/spi.h"
+ #include "foreign/foreign.h"
  #include "lib/stringinfo.h"
  #include "miscadmin.h"
  #include "nodes/execnodes.h"
***************
*** 77,83 ****
  /*
   * Internal declarations
   */
! static Datum dblink_record_internal(FunctionCallInfo fcinfo, bool is_async, bool do_get);
  static remoteConn *getConnectionByName(const char *name);
  static HTAB *createConnHash(void);
  static void createNewConnection(const char *name, remoteConn * rconn);
--- 78,84 ----
  /*
   * Internal declarations
   */
! static Datum dblink_record_internal(FunctionCallInfo fcinfo, bool is_async);
  static remoteConn *getConnectionByName(const char *name);
  static HTAB *createConnHash(void);
  static void createNewConnection(const char *name, remoteConn * rconn);
***************
*** 96,101 ****
--- 97,103 ----
  static void dblink_connstr_check(const char *connstr);
  static void dblink_security_check(PGconn *conn, remoteConn *rconn);
  static void dblink_res_error(const char *conname, PGresult *res, const char *dblink_context_msg, bool fail);
+ static char *get_connect_string(const char *servername);
  
  /* Global */
  static remoteConn *pconn = NULL;
***************
*** 165,171 ****
  			} \
  			else \
  			{ \
! 				connstr = conname_or_str; \
  				dblink_connstr_check(connstr); \
  				conn = PQconnectdb(connstr); \
  				if (PQstatus(conn) == CONNECTION_BAD) \
--- 167,175 ----
  			} \
  			else \
  			{ \
! 				connstr = get_connect_string(conname_or_str); \
! 				if (connstr == NULL) \
! 					connstr = conname_or_str; \
  				dblink_connstr_check(connstr); \
  				conn = PQconnectdb(connstr); \
  				if (PQstatus(conn) == CONNECTION_BAD) \
***************
*** 210,215 ****
--- 214,220 ----
  Datum
  dblink_connect(PG_FUNCTION_ARGS)
  {
+ 	char	   *conname_or_str = NULL;
  	char	   *connstr = NULL;
  	char	   *connname = NULL;
  	char	   *msg;
***************
*** 220,235 ****
  
  	if (PG_NARGS() == 2)
  	{
! 		connstr = text_to_cstring(PG_GETARG_TEXT_PP(1));
  		connname = text_to_cstring(PG_GETARG_TEXT_PP(0));
  	}
  	else if (PG_NARGS() == 1)
! 		connstr = text_to_cstring(PG_GETARG_TEXT_PP(0));
  
  	if (connname)
  		rconn = (remoteConn *) MemoryContextAlloc(TopMemoryContext,
  												  sizeof(remoteConn));
  
  	/* check password in connection string if not superuser */
  	dblink_connstr_check(connstr);
  	conn = PQconnectdb(connstr);
--- 225,245 ----
  
  	if (PG_NARGS() == 2)
  	{
! 		conname_or_str = text_to_cstring(PG_GETARG_TEXT_PP(1));
  		connname = text_to_cstring(PG_GETARG_TEXT_PP(0));
  	}
  	else if (PG_NARGS() == 1)
! 		conname_or_str = text_to_cstring(PG_GETARG_TEXT_PP(0));
  
  	if (connname)
  		rconn = (remoteConn *) MemoryContextAlloc(TopMemoryContext,
  												  sizeof(remoteConn));
  
+ 	/* first check for valid foreign data server */
+ 	connstr = get_connect_string(conname_or_str);
+ 	if (connstr == NULL)
+ 		connstr = conname_or_str;
+ 
  	/* check password in connection string if not superuser */
  	dblink_connstr_check(connstr);
  	conn = PQconnectdb(connstr);
***************
*** 689,713 ****
  Datum
  dblink_record(PG_FUNCTION_ARGS)
  {
! 	return dblink_record_internal(fcinfo, false, false);
  }
  
  PG_FUNCTION_INFO_V1(dblink_send_query);
  Datum
  dblink_send_query(PG_FUNCTION_ARGS)
  {
! 	return dblink_record_internal(fcinfo, true, false);
  }
  
  PG_FUNCTION_INFO_V1(dblink_get_result);
  Datum
  dblink_get_result(PG_FUNCTION_ARGS)
  {
! 	return dblink_record_internal(fcinfo, true, true);
  }
  
  static Datum
! dblink_record_internal(FunctionCallInfo fcinfo, bool is_async, bool do_get)
  {
  	FuncCallContext *funcctx;
  	TupleDesc	tupdesc = NULL;
--- 699,745 ----
  Datum
  dblink_record(PG_FUNCTION_ARGS)
  {
! 	return dblink_record_internal(fcinfo, false);
  }
  
  PG_FUNCTION_INFO_V1(dblink_send_query);
  Datum
  dblink_send_query(PG_FUNCTION_ARGS)
  {
! 	PGconn	   *conn = NULL;
! 	char	   *connstr = NULL;
! 	char	   *sql = NULL;
! 	remoteConn *rconn = NULL;
! 	char	   *msg;
! 	bool		freeconn = false;
! 	int			retval;
! 
! 	if (PG_NARGS() == 2)
! 	{
! 		DBLINK_GET_CONN;
! 		sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
! 	}
! 	else
! 		/* shouldn't happen */
! 		elog(ERROR, "wrong number of arguments");
! 
! 	/* async query send */
! 	retval = PQsendQuery(conn, sql);
! 	if (retval != 1)
! 		elog(NOTICE, "%s", PQerrorMessage(conn));
! 
! 	PG_RETURN_INT32(retval);
  }
  
  PG_FUNCTION_INFO_V1(dblink_get_result);
  Datum
  dblink_get_result(PG_FUNCTION_ARGS)
  {
! 	return dblink_record_internal(fcinfo, true);
  }
  
  static Datum
! dblink_record_internal(FunctionCallInfo fcinfo, bool is_async)
  {
  	FuncCallContext *funcctx;
  	TupleDesc	tupdesc = NULL;
***************
*** 775,788 ****
  				/* shouldn't happen */
  				elog(ERROR, "wrong number of arguments");
  		}
! 		else if (is_async && do_get)
  		{
  			/* get async result */
  			if (PG_NARGS() == 2)
  			{
  				/* text,bool */
  				DBLINK_GET_CONN;
! 				fail = PG_GETARG_BOOL(2);
  			}
  			else if (PG_NARGS() == 1)
  			{
--- 807,820 ----
  				/* shouldn't happen */
  				elog(ERROR, "wrong number of arguments");
  		}
! 		else /* is_async */
  		{
  			/* get async result */
  			if (PG_NARGS() == 2)
  			{
  				/* text,bool */
  				DBLINK_GET_CONN;
! 				fail = PG_GETARG_BOOL(1);
  			}
  			else if (PG_NARGS() == 1)
  			{
***************
*** 793,929 ****
  				/* shouldn't happen */
  				elog(ERROR, "wrong number of arguments");
  		}
- 		else
- 		{
- 			/* send async query */
- 			if (PG_NARGS() == 2)
- 			{
- 				DBLINK_GET_CONN;
- 				sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
- 			}
- 			else
- 				/* shouldn't happen */
- 				elog(ERROR, "wrong number of arguments");
- 		}
  
  		if (!conn)
  			DBLINK_CONN_NOT_AVAIL;
  
! 		if (!is_async || (is_async && do_get))
  		{
! 			/* synchronous query, or async result retrieval */
! 			if (!is_async)
! 				res = PQexec(conn, sql);
! 			else
! 			{
! 				res = PQgetResult(conn);
! 				/* NULL means we're all done with the async results */
! 				if (!res)
! 				{
! 					MemoryContextSwitchTo(oldcontext);
! 					SRF_RETURN_DONE(funcctx);
! 				}
! 			}
! 
! 			if (!res ||
! 				(PQresultStatus(res) != PGRES_COMMAND_OK &&
! 				 PQresultStatus(res) != PGRES_TUPLES_OK))
  			{
- 				dblink_res_error(conname, res, "could not execute query", fail);
- 				if (freeconn)
- 					PQfinish(conn);
  				MemoryContextSwitchTo(oldcontext);
  				SRF_RETURN_DONE(funcctx);
  			}
  
! 			if (PQresultStatus(res) == PGRES_COMMAND_OK)
! 			{
! 				is_sql_cmd = true;
! 
! 				/* need a tuple descriptor representing one TEXT column */
! 				tupdesc = CreateTemplateTupleDesc(1, false);
! 				TupleDescInitEntry(tupdesc, (AttrNumber) 1, "status",
! 								   TEXTOID, -1, 0);
! 
! 				/*
! 				 * and save a copy of the command status string to return as
! 				 * our result tuple
! 				 */
! 				sql_cmd_status = PQcmdStatus(res);
! 				funcctx->max_calls = 1;
! 			}
! 			else
! 				funcctx->max_calls = PQntuples(res);
! 
! 			/* got results, keep track of them */
! 			funcctx->user_fctx = res;
! 
! 			/* if needed, close the connection to the database and cleanup */
  			if (freeconn)
  				PQfinish(conn);
  
! 			if (!is_sql_cmd)
! 			{
! 				/* get a tuple descriptor for our result type */
! 				switch (get_call_result_type(fcinfo, NULL, &tupdesc))
! 				{
! 					case TYPEFUNC_COMPOSITE:
! 						/* success */
! 						break;
! 					case TYPEFUNC_RECORD:
! 						/* failed to determine actual type of RECORD */
! 						ereport(ERROR,
! 								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
! 						errmsg("function returning record called in context "
! 							   "that cannot accept type record")));
! 						break;
! 					default:
! 						/* result type isn't composite */
! 						elog(ERROR, "return type must be a row type");
! 						break;
! 				}
  
! 				/* make sure we have a persistent copy of the tupdesc */
! 				tupdesc = CreateTupleDescCopy(tupdesc);
! 			}
  
  			/*
! 			 * check result and tuple descriptor have the same number of
! 			 * columns
  			 */
! 			if (PQnfields(res) != tupdesc->natts)
! 				ereport(ERROR,
! 						(errcode(ERRCODE_DATATYPE_MISMATCH),
! 						 errmsg("remote query result rowtype does not match "
! 								"the specified FROM clause rowtype")));
  
! 			/* fast track when no results */
! 			if (funcctx->max_calls < 1)
  			{
! 				if (res)
! 					PQclear(res);
! 				MemoryContextSwitchTo(oldcontext);
! 				SRF_RETURN_DONE(funcctx);
  			}
  
! 			/* store needed metadata for subsequent calls */
! 			attinmeta = TupleDescGetAttInMetadata(tupdesc);
! 			funcctx->attinmeta = attinmeta;
! 
! 			MemoryContextSwitchTo(oldcontext);
  		}
! 		else
  		{
! 			/* async query send */
  			MemoryContextSwitchTo(oldcontext);
! 			PG_RETURN_INT32(PQsendQuery(conn, sql));
  		}
- 	}
  
! 	if (is_async && !do_get)
! 	{
! 		/* async query send -- should not happen */
! 		elog(ERROR, "async query send called more than once");
  
  	}
  
--- 825,934 ----
  				/* shouldn't happen */
  				elog(ERROR, "wrong number of arguments");
  		}
  
  		if (!conn)
  			DBLINK_CONN_NOT_AVAIL;
  
! 		/* synchronous query, or async result retrieval */
! 		if (!is_async)
! 			res = PQexec(conn, sql);
! 		else
  		{
! 			res = PQgetResult(conn);
! 			/* NULL means we're all done with the async results */
! 			if (!res)
  			{
  				MemoryContextSwitchTo(oldcontext);
  				SRF_RETURN_DONE(funcctx);
  			}
+ 		}
  
! 		if (!res ||
! 			(PQresultStatus(res) != PGRES_COMMAND_OK &&
! 			 PQresultStatus(res) != PGRES_TUPLES_OK))
! 		{
! 			dblink_res_error(conname, res, "could not execute query", fail);
  			if (freeconn)
  				PQfinish(conn);
+ 			MemoryContextSwitchTo(oldcontext);
+ 			SRF_RETURN_DONE(funcctx);
+ 		}
  
! 		if (PQresultStatus(res) == PGRES_COMMAND_OK)
! 		{
! 			is_sql_cmd = true;
  
! 			/* need a tuple descriptor representing one TEXT column */
! 			tupdesc = CreateTemplateTupleDesc(1, false);
! 			TupleDescInitEntry(tupdesc, (AttrNumber) 1, "status",
! 							   TEXTOID, -1, 0);
  
  			/*
! 			 * and save a copy of the command status string to return as
! 			 * our result tuple
  			 */
! 			sql_cmd_status = PQcmdStatus(res);
! 			funcctx->max_calls = 1;
! 		}
! 		else
! 			funcctx->max_calls = PQntuples(res);
  
! 		/* got results, keep track of them */
! 		funcctx->user_fctx = res;
! 
! 		/* if needed, close the connection to the database and cleanup */
! 		if (freeconn)
! 			PQfinish(conn);
! 
! 		if (!is_sql_cmd)
! 		{
! 			/* get a tuple descriptor for our result type */
! 			switch (get_call_result_type(fcinfo, NULL, &tupdesc))
  			{
! 				case TYPEFUNC_COMPOSITE:
! 					/* success */
! 					break;
! 				case TYPEFUNC_RECORD:
! 					/* failed to determine actual type of RECORD */
! 					ereport(ERROR,
! 							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
! 					errmsg("function returning record called in context "
! 						   "that cannot accept type record")));
! 					break;
! 				default:
! 					/* result type isn't composite */
! 					elog(ERROR, "return type must be a row type");
! 					break;
  			}
  
! 			/* make sure we have a persistent copy of the tupdesc */
! 			tupdesc = CreateTupleDescCopy(tupdesc);
  		}
! 
! 		/*
! 		 * check result and tuple descriptor have the same number of
! 		 * columns
! 		 */
! 		if (PQnfields(res) != tupdesc->natts)
! 			ereport(ERROR,
! 					(errcode(ERRCODE_DATATYPE_MISMATCH),
! 					 errmsg("remote query result rowtype does not match "
! 							"the specified FROM clause rowtype")));
! 
! 		/* fast track when no results */
! 		if (funcctx->max_calls < 1)
  		{
! 			if (res)
! 				PQclear(res);
  			MemoryContextSwitchTo(oldcontext);
! 			SRF_RETURN_DONE(funcctx);
  		}
  
! 		/* store needed metadata for subsequent calls */
! 		attinmeta = TupleDescGetAttInMetadata(tupdesc);
! 		funcctx->attinmeta = attinmeta;
! 
! 		MemoryContextSwitchTo(oldcontext);
  
  	}
  
***************
*** 2358,2360 ****
--- 2363,2405 ----
  		 errcontext("Error occurred on dblink connection named \"%s\": %s.",
  					dblink_context_conname, dblink_context_msg)));
  }
+ 
+ /*
+  * Obtain connection string for a foreign server
+  */
+ static char *
+ get_connect_string(const char *servername)
+ {
+ 	ForeignServer	   *foreign_server;
+ 	UserMapping		   *user_mapping;
+ 	ListCell		   *cell;
+ 	StringInfo			buf = makeStringInfo();
+ 
+ 	/* first gather the server connstr options */
+ 	foreign_server = GetForeignServerByName(servername, true);
+ 
+ 	if (foreign_server)
+ 	{
+ 		foreach (cell, foreign_server->options)
+ 		{
+ 	
+ 			DefElem		   *def = lfirst(cell);
+ 	
+ 			appendStringInfo(buf, "%s='%s' ", def->defname, strVal(def->arg));
+ 		}
+ 	
+ 		/* next get the user connstr options */
+ 		user_mapping = GetUserMapping(GetUserId(), foreign_server->serverid);
+ 		foreach (cell, user_mapping->options)
+ 		{
+ 	
+ 			DefElem		   *def = lfirst(cell);
+ 	
+ 			appendStringInfo(buf, "%s='%s' ", def->defname, strVal(def->arg));
+ 		}
+ 
+ 		return pstrdup(buf->data);
+ 	}
+ 	else
+ 		return NULL;
+ }
Index: contrib/dblink/expected/dblink.out
===================================================================
RCS file: /opt/src/cvs/pgsql/contrib/dblink/expected/dblink.out,v
retrieving revision 1.24
diff -c -r1.24 dblink.out
*** contrib/dblink/expected/dblink.out	3 Jul 2008 03:56:57 -0000	1.24
--- contrib/dblink/expected/dblink.out	3 Jan 2009 02:56:06 -0000
***************
*** 784,786 ****
--- 784,819 ----
   OK
  (1 row)
  
+ -- test foreign data wrapper functionality
+ CREATE USER dblink_regression_test;
+ CREATE FOREIGN DATA WRAPPER postgresql LIBRARY 'postgresql_fdw' LANGUAGE C;
+ CREATE SERVER fdtest FOREIGN DATA WRAPPER postgresql OPTIONS (dbname 'contrib_regression');
+ CREATE USER MAPPING FOR public SERVER fdtest;
+ GRANT EXECUTE ON FUNCTION dblink_connect_u(text, text) TO dblink_regression_test;
+ \set ORIGINAL_USER :USER
+ \c - dblink_regression_test
+ SELECT dblink_connect_u('myconn', 'fdtest');
+  dblink_connect_u 
+ ------------------
+  OK
+ (1 row)
+ 
+ SELECT * FROM dblink('myconn','SELECT * FROM foo') AS t(a int, b text, c text[]);
+  a  | b |       c       
+ ----+---+---------------
+   0 | a | {a0,b0,c0}
+   1 | b | {a1,b1,c1}
+   2 | c | {a2,b2,c2}
+   3 | d | {a3,b3,c3}
+   4 | e | {a4,b4,c4}
+   5 | f | {a5,b5,c5}
+   6 | g | {a6,b6,c6}
+   7 | h | {a7,b7,c7}
+   8 | i | {a8,b8,c8}
+   9 | j | {a9,b9,c9}
+  10 | k | {a10,b10,c10}
+ (11 rows)
+ 
+ \c - :ORIGINAL_USER
+ REVOKE EXECUTE ON FUNCTION dblink_connect_u(text, text) FROM dblink_regression_test;
+ DROP USER dblink_regression_test;
Index: contrib/dblink/sql/dblink.sql
===================================================================
RCS file: /opt/src/cvs/pgsql/contrib/dblink/sql/dblink.sql,v
retrieving revision 1.20
diff -c -r1.20 dblink.sql
*** contrib/dblink/sql/dblink.sql	6 Apr 2008 16:54:48 -0000	1.20
--- contrib/dblink/sql/dblink.sql	3 Jan 2009 02:54:29 -0000
***************
*** 364,366 ****
--- 364,383 ----
  SELECT dblink_cancel_query('dtest1');
  SELECT dblink_error_message('dtest1');
  SELECT dblink_disconnect('dtest1');
+ 
+ -- test foreign data wrapper functionality
+ CREATE USER dblink_regression_test;
+ 
+ CREATE FOREIGN DATA WRAPPER postgresql LIBRARY 'postgresql_fdw' LANGUAGE C;
+ CREATE SERVER fdtest FOREIGN DATA WRAPPER postgresql OPTIONS (dbname 'contrib_regression');
+ CREATE USER MAPPING FOR public SERVER fdtest;
+ GRANT EXECUTE ON FUNCTION dblink_connect_u(text, text) TO dblink_regression_test;
+ 
+ \set ORIGINAL_USER :USER
+ \c - dblink_regression_test
+ SELECT dblink_connect_u('myconn', 'fdtest');
+ SELECT * FROM dblink('myconn','SELECT * FROM foo') AS t(a int, b text, c text[]);
+ 
+ \c - :ORIGINAL_USER
+ REVOKE EXECUTE ON FUNCTION dblink_connect_u(text, text) FROM dblink_regression_test;
+ DROP USER dblink_regression_test;
Index: doc/src/sgml/dblink.sgml
===================================================================
RCS file: /opt/src/cvs/pgsql/doc/src/sgml/dblink.sgml,v
retrieving revision 1.6
diff -c -r1.6 dblink.sgml
*** doc/src/sgml/dblink.sgml	12 Nov 2008 15:52:44 -0000	1.6
--- doc/src/sgml/dblink.sgml	3 Jan 2009 06:25:10 -0000
***************
*** 42,47 ****
--- 42,59 ----
      only one unnamed connection is permitted at a time.  The connection
      will persist until closed or until the database session is ended.
     </para>
+ 
+    <para>
+     The connection string may also be the name of an existing foreign
+     server that utilizes the postgresql_fdw foreign data wrapper library.
+     See the example below, as well as the following:
+     <simplelist type="inline">
+      <member><xref linkend="sql-createforeigndatawrapper" endterm="sql-createforeigndatawrapper-title"></member>
+      <member><xref linkend="sql-createserver" endterm="sql-createserver-title"></member>
+      <member><xref linkend="sql-createusermapping" endterm="sql-createusermapping-title"></member>
+     </simplelist>
+    </para>
+ 
    </refsect1>
  
    <refsect1>
***************
*** 113,118 ****
--- 125,168 ----
   ----------------
    OK
   (1 row)
+ 
+  -- FOREIGN DATA WRAPPER functionality
+  -- Note: local connection must require authentication for this to work properly
+  CREATE USER dblink_regression_test WITH PASSWORD 'secret';
+  -- The next two statements are unneeded in the contrib_regression database as they
+  -- have already been performed. They will produce ERROR messages.
+  CREATE FOREIGN DATA WRAPPER postgresql LIBRARY 'postgresql_fdw' LANGUAGE C;
+  CREATE SERVER fdtest FOREIGN DATA WRAPPER postgresql OPTIONS (dbname 'contrib_regression');
+  CREATE USER MAPPING FOR dblink_regression_test SERVER fdtest OPTIONS (user 'dblink_regression_test', password 'secret');
+  GRANT SELECT ON TABLE foo TO dblink_regression_test;
+  \set ORIGINAL_USER :USER
+  \c - dblink_regression_test
+  SELECT dblink_connect('myconn', 'fdtest');
+   dblink_connect 
+  ----------------
+   OK
+  (1 row)
+ 
+  SELECT * FROM dblink('myconn','SELECT * FROM foo') AS t(a int, b text, c text[]);
+   a  | b |       c       
+  ----+---+---------------
+    0 | a | {a0,b0,c0}
+    1 | b | {a1,b1,c1}
+    2 | c | {a2,b2,c2}
+    3 | d | {a3,b3,c3}
+    4 | e | {a4,b4,c4}
+    5 | f | {a5,b5,c5}
+    6 | g | {a6,b6,c6}
+    7 | h | {a7,b7,c7}
+    8 | i | {a8,b8,c8}
+    9 | j | {a9,b9,c9}
+   10 | k | {a10,b10,c10}
+  (11 rows)
+ 
+  \c - :ORIGINAL_USER
+  REVOKE SELECT ON TABLE foo FROM dblink_regression_test;
+  DROP USER MAPPING FOR dblink_regression_test SERVER fdtest;
+  DROP USER dblink_regression_test;
     </programlisting>
    </refsect1>
   </refentry>