Merge from PG master upto d5cb3bab564e0927ffac7c8729eacf181a12dd40

This is the result of the "git merge remotes/PGSQL/master" upto the said commit
point. We have done some basic analysis, fixed compilation problems etc, but
bulk of the logical problems in conflict resolution etc will be handled by
subsequent commits.

1 files changed, 235 insertions, 196 deletions

diff --git a/contrib/dblink/dblink.c b/contrib/dblink/dblink.c
index 9c8e308358..a6a3c09ff8 100644
--- a/contrib/dblink/dblink.c
+++ b/contrib/dblink/dblink.c
@@ -9,7 +9,7 @@
  * Shridhar Daithankar <shridhar_daithankar@persistent.co.in>
  *
  * contrib/dblink/dblink.c
- * Copyright (c) 2001-2016, PostgreSQL Global Development Group
+ * Copyright (c) 2001-2017, PostgreSQL Global Development Group
  * ALL RIGHTS RESERVED;
  *
  * Permission to use, copy, modify, and distribute this software and its
@@ -40,6 +40,7 @@
 #include "access/reloptions.h"
 #include "catalog/indexing.h"
 #include "catalog/namespace.h"
+#include "catalog/pg_foreign_data_wrapper.h"
 #include "catalog/pg_foreign_server.h"
 #include "catalog/pg_type.h"
 #include "catalog/pg_user_mapping.h"
@@ -58,8 +59,7 @@
 #include "utils/memutils.h"
 #include "utils/rel.h"
 #include "utils/tqual.h"
-
-#include "dblink.h"
+#include "utils/varlena.h"
 
 PG_MODULE_MAGIC;
 
@@ -112,7 +112,8 @@ static Relation get_rel_from_relname(text *relname_text, LOCKMODE lockmode, AclM
 static char *generate_relation_name(Relation rel);
 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 void dblink_res_error(PGconn *conn, const char *conname, PGresult *res,
+				 const char *dblink_context_msg, bool fail);
 static char *get_connect_string(const char *servername);
 static char *escape_param_str(const char *from);
 static void validate_pkattnums(Relation rel,
@@ -143,98 +144,108 @@ typedef struct remoteConnHashEnt
 /* initial number of connection hashes */
 #define NUMCONN 16
 
-/* general utility */
-#define xpfree(var_) \
-	do { \
-		if (var_ != NULL) \
-		{ \
-			pfree(var_); \
-			var_ = NULL; \
-		} \
-	} while (0)
-
-#define xpstrdup(var_c, var_) \
-	do { \
-		if (var_ != NULL) \
-			var_c = pstrdup(var_); \
-		else \
-			var_c = NULL; \
-	} while (0)
-
-#define DBLINK_RES_INTERNALERROR(p2) \
-	do { \
-			msg = pstrdup(PQerrorMessage(conn)); \
-			if (res) \
-				PQclear(res); \
-			elog(ERROR, "%s: %s", p2, msg); \
-	} while (0)
-
-#define DBLINK_CONN_NOT_AVAIL \
-	do { \
-		if(conname) \
-			ereport(ERROR, \
-					(errcode(ERRCODE_CONNECTION_DOES_NOT_EXIST), \
-					 errmsg("connection \"%s\" not available", conname))); \
-		else \
-			ereport(ERROR, \
-					(errcode(ERRCODE_CONNECTION_DOES_NOT_EXIST), \
-					 errmsg("connection not available"))); \
-	} while (0)
-
-#define DBLINK_GET_CONN \
-	do { \
-			char *conname_or_str = text_to_cstring(PG_GETARG_TEXT_PP(0)); \
-			rconn = getConnectionByName(conname_or_str); \
-			if (rconn) \
-			{ \
-				conn = rconn->conn; \
-				conname = conname_or_str; \
-			} \
-			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) \
-				{ \
-					msg = pstrdup(PQerrorMessage(conn)); \
-					PQfinish(conn); \
-					ereport(ERROR, \
-							(errcode(ERRCODE_SQLCLIENT_UNABLE_TO_ESTABLISH_SQLCONNECTION), \
-							 errmsg("could not establish connection"), \
-							 errdetail_internal("%s", msg))); \
-				} \
-				dblink_security_check(conn, rconn); \
-				if (PQclientEncoding(conn) != GetDatabaseEncoding()) \
-					PQsetClientEncoding(conn, GetDatabaseEncodingName()); \
-				freeconn = true; \
-			} \
-	} while (0)
-
-#define DBLINK_GET_NAMED_CONN \
-	do { \
-			conname = text_to_cstring(PG_GETARG_TEXT_PP(0)); \
-			rconn = getConnectionByName(conname); \
-			if (rconn) \
-				conn = rconn->conn; \
-			else \
-				DBLINK_CONN_NOT_AVAIL; \
-	} while (0)
-
-#define DBLINK_INIT \
-	do { \
-			if (!pconn) \
-			{ \
-				pconn = (remoteConn *) MemoryContextAlloc(TopMemoryContext, sizeof(remoteConn)); \
-				pconn->conn = NULL; \
-				pconn->openCursorCount = 0; \
-				pconn->newXactForCursor = FALSE; \
-			} \
-	} while (0)
+static char *
+xpstrdup(const char *in)
+{
+	if (in == NULL)
+		return NULL;
+	return pstrdup(in);
+}
+
+static void
+pg_attribute_noreturn()
+dblink_res_internalerror(PGconn *conn, PGresult *res, const char *p2)
+{
+	char	   *msg = pchomp(PQerrorMessage(conn));
+
+	if (res)
+		PQclear(res);
+	elog(ERROR, "%s: %s", p2, msg);
+}
+
+static void
+pg_attribute_noreturn()
+dblink_conn_not_avail(const char *conname)
+{
+	if (conname)
+		ereport(ERROR,
+				(errcode(ERRCODE_CONNECTION_DOES_NOT_EXIST),
+				 errmsg("connection \"%s\" not available", conname)));
+	else
+		ereport(ERROR,
+				(errcode(ERRCODE_CONNECTION_DOES_NOT_EXIST),
+				 errmsg("connection not available")));
+}
+
+static void
+dblink_get_conn(char *conname_or_str,
+	  PGconn *volatile * conn_p, char **conname_p, volatile bool *freeconn_p)
+{
+	remoteConn *rconn = getConnectionByName(conname_or_str);
+	PGconn	   *conn;
+	char	   *conname;
+	bool		freeconn;
+
+	if (rconn)
+	{
+		conn = rconn->conn;
+		conname = conname_or_str;
+		freeconn = false;
+	}
+	else
+	{
+		const char *connstr;
+
+		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)
+		{
+			char	   *msg = pchomp(PQerrorMessage(conn));
+
+			PQfinish(conn);
+			ereport(ERROR,
+			   (errcode(ERRCODE_SQLCLIENT_UNABLE_TO_ESTABLISH_SQLCONNECTION),
+				errmsg("could not establish connection"),
+				errdetail_internal("%s", msg)));
+		}
+		dblink_security_check(conn, rconn);
+		if (PQclientEncoding(conn) != GetDatabaseEncoding())
+			PQsetClientEncoding(conn, GetDatabaseEncodingName());
+		freeconn = true;
+		conname = NULL;
+	}
+
+	*conn_p = conn;
+	*conname_p = conname;
+	*freeconn_p = freeconn;
+}
+
+static PGconn *
+dblink_get_named_conn(const char *conname)
+{
+	remoteConn *rconn = getConnectionByName(conname);
+
+	if (rconn)
+		return rconn->conn;
+
+	dblink_conn_not_avail(conname);
+	return NULL;				/* keep compiler quiet */
+}
+
+static void
+dblink_init(void)
+{
+	if (!pconn)
+	{
+		pconn = (remoteConn *) MemoryContextAlloc(TopMemoryContext, sizeof(remoteConn));
+		pconn->conn = NULL;
+		pconn->openCursorCount = 0;
+		pconn->newXactForCursor = FALSE;
+	}
+}
 
 /*
  * Create a persistent connection to another database
@@ -250,7 +261,7 @@ dblink_connect(PG_FUNCTION_ARGS)
 	PGconn	   *conn = NULL;
 	remoteConn *rconn = NULL;
 
-	DBLINK_INIT;
+	dblink_init();
 
 	if (PG_NARGS() == 2)
 	{
@@ -275,7 +286,7 @@ dblink_connect(PG_FUNCTION_ARGS)
 
 	if (PQstatus(conn) == CONNECTION_BAD)
 	{
-		msg = pstrdup(PQerrorMessage(conn));
+		msg = pchomp(PQerrorMessage(conn));
 		PQfinish(conn);
 		if (rconn)
 			pfree(rconn);
@@ -299,7 +310,11 @@ dblink_connect(PG_FUNCTION_ARGS)
 		createNewConnection(connname, rconn);
 	}
 	else
+	{
+		if (pconn->conn)
+			PQfinish(pconn->conn);
 		pconn->conn = conn;
+	}
 
 	PG_RETURN_TEXT_P(cstring_to_text("OK"));
 }
@@ -315,7 +330,7 @@ dblink_disconnect(PG_FUNCTION_ARGS)
 	remoteConn *rconn = NULL;
 	PGconn	   *conn = NULL;
 
-	DBLINK_INIT;
+	dblink_init();
 
 	if (PG_NARGS() == 1)
 	{
@@ -328,7 +343,7 @@ dblink_disconnect(PG_FUNCTION_ARGS)
 		conn = pconn->conn;
 
 	if (!conn)
-		DBLINK_CONN_NOT_AVAIL;
+		dblink_conn_not_avail(conname);
 
 	PQfinish(conn);
 	if (rconn)
@@ -349,9 +364,8 @@ PG_FUNCTION_INFO_V1(dblink_open);
 Datum
 dblink_open(PG_FUNCTION_ARGS)
 {
-	char	   *msg;
 	PGresult   *res = NULL;
-	PGconn	   *conn = NULL;
+	PGconn	   *conn;
 	char	   *curname = NULL;
 	char	   *sql = NULL;
 	char	   *conname = NULL;
@@ -359,7 +373,7 @@ dblink_open(PG_FUNCTION_ARGS)
 	remoteConn *rconn = NULL;
 	bool		fail = true;	/* default to backward compatible behavior */
 
-	DBLINK_INIT;
+	dblink_init();
 	initStringInfo(&buf);
 
 	if (PG_NARGS() == 2)
@@ -398,16 +412,16 @@ dblink_open(PG_FUNCTION_ARGS)
 	}
 
 	if (!rconn || !rconn->conn)
-		DBLINK_CONN_NOT_AVAIL;
-	else
-		conn = rconn->conn;
+		dblink_conn_not_avail(conname);
+
+	conn = rconn->conn;
 
 	/* If we are not in a transaction, start one */
 	if (PQtransactionStatus(conn) == PQTRANS_IDLE)
 	{
 		res = PQexec(conn, "BEGIN");
 		if (PQresultStatus(res) != PGRES_COMMAND_OK)
-			DBLINK_RES_INTERNALERROR("begin error");
+			dblink_res_internalerror(conn, res, "begin error");
 		PQclear(res);
 		rconn->newXactForCursor = TRUE;
 
@@ -427,7 +441,7 @@ dblink_open(PG_FUNCTION_ARGS)
 	res = PQexec(conn, buf.data);
 	if (!res || PQresultStatus(res) != PGRES_COMMAND_OK)
 	{
-		dblink_res_error(conname, res, "could not open cursor", fail);
+		dblink_res_error(conn, conname, res, "could not open cursor", fail);
 		PG_RETURN_TEXT_P(cstring_to_text("ERROR"));
 	}
 
@@ -442,16 +456,15 @@ PG_FUNCTION_INFO_V1(dblink_close);
 Datum
 dblink_close(PG_FUNCTION_ARGS)
 {
-	PGconn	   *conn = NULL;
+	PGconn	   *conn;
 	PGresult   *res = NULL;
 	char	   *curname = NULL;
 	char	   *conname = NULL;
 	StringInfoData buf;
-	char	   *msg;
 	remoteConn *rconn = NULL;
 	bool		fail = true;	/* default to backward compatible behavior */
 
-	DBLINK_INIT;
+	dblink_init();
 	initStringInfo(&buf);
 
 	if (PG_NARGS() == 1)
@@ -486,9 +499,9 @@ dblink_close(PG_FUNCTION_ARGS)
 	}
 
 	if (!rconn || !rconn->conn)
-		DBLINK_CONN_NOT_AVAIL;
-	else
-		conn = rconn->conn;
+		dblink_conn_not_avail(conname);
+
+	conn = rconn->conn;
 
 	appendStringInfo(&buf, "CLOSE %s", curname);
 
@@ -496,7 +509,7 @@ dblink_close(PG_FUNCTION_ARGS)
 	res = PQexec(conn, buf.data);
 	if (!res || PQresultStatus(res) != PGRES_COMMAND_OK)
 	{
-		dblink_res_error(conname, res, "could not close cursor", fail);
+		dblink_res_error(conn, conname, res, "could not close cursor", fail);
 		PG_RETURN_TEXT_P(cstring_to_text("ERROR"));
 	}
 
@@ -514,7 +527,7 @@ dblink_close(PG_FUNCTION_ARGS)
 
 			res = PQexec(conn, "COMMIT");
 			if (PQresultStatus(res) != PGRES_COMMAND_OK)
-				DBLINK_RES_INTERNALERROR("commit error");
+				dblink_res_internalerror(conn, res, "commit error");
 			PQclear(res);
 		}
 	}
@@ -540,7 +553,7 @@ dblink_fetch(PG_FUNCTION_ARGS)
 
 	prepTuplestoreResult(fcinfo);
 
-	DBLINK_INIT;
+	dblink_init();
 
 	if (PG_NARGS() == 4)
 	{
@@ -584,7 +597,7 @@ dblink_fetch(PG_FUNCTION_ARGS)
 	}
 
 	if (!conn)
-		DBLINK_CONN_NOT_AVAIL;
+		dblink_conn_not_avail(conname);
 
 	initStringInfo(&buf);
 	appendStringInfo(&buf, "FETCH %d FROM %s", howmany, curname);
@@ -599,7 +612,8 @@ dblink_fetch(PG_FUNCTION_ARGS)
 		(PQresultStatus(res) != PGRES_COMMAND_OK &&
 		 PQresultStatus(res) != PGRES_TUPLES_OK))
 	{
-		dblink_res_error(conname, res, "could not fetch from cursor", fail);
+		dblink_res_error(conn, conname, res,
+						 "could not fetch from cursor", fail);
 		return (Datum) 0;
 	}
 	else if (PQresultStatus(res) == PGRES_COMMAND_OK)
@@ -629,15 +643,13 @@ PG_FUNCTION_INFO_V1(dblink_send_query);
 Datum
 dblink_send_query(PG_FUNCTION_ARGS)
 {
-	char	   *conname = NULL;
-	PGconn	   *conn = NULL;
-	char	   *sql = NULL;
-	remoteConn *rconn = NULL;
+	PGconn	   *conn;
+	char	   *sql;
 	int			retval;
 
 	if (PG_NARGS() == 2)
 	{
-		DBLINK_GET_NAMED_CONN;
+		conn = dblink_get_named_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)));
 		sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
 	}
 	else
@@ -647,7 +659,7 @@ dblink_send_query(PG_FUNCTION_ARGS)
 	/* async query send */
 	retval = PQsendQuery(conn, sql);
 	if (retval != 1)
-		elog(NOTICE, "could not send query: %s", PQerrorMessage(conn));
+		elog(NOTICE, "could not send query: %s", pchomp(PQerrorMessage(conn)));
 
 	PG_RETURN_INT32(retval);
 }
@@ -667,15 +679,12 @@ dblink_record_internal(FunctionCallInfo fcinfo, bool is_async)
 
 	prepTuplestoreResult(fcinfo);
 
-	DBLINK_INIT;
+	dblink_init();
 
 	PG_TRY();
 	{
-		char	   *msg;
-		char	   *connstr = NULL;
 		char	   *sql = NULL;
 		char	   *conname = NULL;
-		remoteConn *rconn = NULL;
 		bool		fail = true;	/* default to backward compatible */
 
 		if (!is_async)
@@ -683,23 +692,25 @@ dblink_record_internal(FunctionCallInfo fcinfo, bool is_async)
 			if (PG_NARGS() == 3)
 			{
 				/* text,text,bool */
-				DBLINK_GET_CONN;
+				conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
 				sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
 				fail = PG_GETARG_BOOL(2);
+				dblink_get_conn(conname, &conn, &conname, &freeconn);
 			}
 			else if (PG_NARGS() == 2)
 			{
 				/* text,text or text,bool */
 				if (get_fn_expr_argtype(fcinfo->flinfo, 1) == BOOLOID)
 				{
-					conn = pconn->conn;
 					sql = text_to_cstring(PG_GETARG_TEXT_PP(0));
 					fail = PG_GETARG_BOOL(1);
+					conn = pconn->conn;
 				}
 				else
 				{
-					DBLINK_GET_CONN;
+					conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
 					sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
+					dblink_get_conn(conname, &conn, &conname, &freeconn);
 				}
 			}
 			else if (PG_NARGS() == 1)
@@ -715,16 +726,18 @@ dblink_record_internal(FunctionCallInfo fcinfo, bool is_async)
 		else	/* is_async */
 		{
 			/* get async result */
+			conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
+
 			if (PG_NARGS() == 2)
 			{
 				/* text,bool */
-				DBLINK_GET_NAMED_CONN;
 				fail = PG_GETARG_BOOL(1);
+				conn = dblink_get_named_conn(conname);
 			}
 			else if (PG_NARGS() == 1)
 			{
 				/* text */
-				DBLINK_GET_NAMED_CONN;
+				conn = dblink_get_named_conn(conname);
 			}
 			else
 				/* shouldn't happen */
@@ -732,7 +745,7 @@ dblink_record_internal(FunctionCallInfo fcinfo, bool is_async)
 		}
 
 		if (!conn)
-			DBLINK_CONN_NOT_AVAIL;
+			dblink_conn_not_avail(conname);
 
 		if (!is_async)
 		{
@@ -750,8 +763,8 @@ dblink_record_internal(FunctionCallInfo fcinfo, bool is_async)
 				if (PQresultStatus(res) != PGRES_COMMAND_OK &&
 					PQresultStatus(res) != PGRES_TUPLES_OK)
 				{
-					dblink_res_error(conname, res, "could not execute query",
-									 fail);
+					dblink_res_error(conn, conname, res,
+									 "could not execute query", fail);
 					/* if fail isn't set, we'll return an empty query result */
 				}
 				else
@@ -980,9 +993,7 @@ materializeQueryResult(FunctionCallInfo fcinfo,
 		/* Create short-lived memory context for data conversions */
 		sinfo.tmpcontext = AllocSetContextCreate(CurrentMemoryContext,
 												 "dblink temporary context",
-												 ALLOCSET_DEFAULT_MINSIZE,
-												 ALLOCSET_DEFAULT_INITSIZE,
-												 ALLOCSET_DEFAULT_MAXSIZE);
+												 ALLOCSET_DEFAULT_SIZES);
 
 		/* execute query, collecting any tuples into the tuplestore */
 		res = storeQueryResult(&sinfo, conn, sql);
@@ -998,7 +1009,8 @@ materializeQueryResult(FunctionCallInfo fcinfo,
 			PGresult   *res1 = res;
 
 			res = NULL;
-			dblink_res_error(conname, res1, "could not execute query", fail);
+			dblink_res_error(conn, conname, res1,
+							 "could not execute query", fail);
 			/* if fail isn't set, we'll return an empty query result */
 		}
 		else if (PQresultStatus(res) == PGRES_COMMAND_OK)
@@ -1084,7 +1096,7 @@ storeQueryResult(volatile storeInfo *sinfo, PGconn *conn, const char *sql)
 	PGresult   *res;
 
 	if (!PQsendQuery(conn, sql))
-		elog(ERROR, "could not send query: %s", PQerrorMessage(conn));
+		elog(ERROR, "could not send query: %s", pchomp(PQerrorMessage(conn)));
 
 	if (!PQsetSingleRowMode(conn))		/* shouldn't fail */
 		elog(ERROR, "failed to set single-row mode for dblink query");
@@ -1294,12 +1306,10 @@ PG_FUNCTION_INFO_V1(dblink_is_busy);
 Datum
 dblink_is_busy(PG_FUNCTION_ARGS)
 {
-	char	   *conname = NULL;
-	PGconn	   *conn = NULL;
-	remoteConn *rconn = NULL;
+	PGconn	   *conn;
 
-	DBLINK_INIT;
-	DBLINK_GET_NAMED_CONN;
+	dblink_init();
+	conn = dblink_get_named_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)));
 
 	PQconsumeInput(conn);
 	PG_RETURN_INT32(PQisBusy(conn));
@@ -1320,15 +1330,13 @@ PG_FUNCTION_INFO_V1(dblink_cancel_query);
 Datum
 dblink_cancel_query(PG_FUNCTION_ARGS)
 {
-	int			res = 0;
-	char	   *conname = NULL;
-	PGconn	   *conn = NULL;
-	remoteConn *rconn = NULL;
+	int			res;
+	PGconn	   *conn;
 	PGcancel   *cancel;
 	char		errbuf[256];
 
-	DBLINK_INIT;
-	DBLINK_GET_NAMED_CONN;
+	dblink_init();
+	conn = dblink_get_named_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)));
 	cancel = PQgetCancel(conn);
 
 	res = PQcancel(cancel, errbuf, 256);
@@ -1356,18 +1364,16 @@ Datum
 dblink_error_message(PG_FUNCTION_ARGS)
 {
 	char	   *msg;
-	char	   *conname = NULL;
-	PGconn	   *conn = NULL;
-	remoteConn *rconn = NULL;
+	PGconn	   *conn;
 
-	DBLINK_INIT;
-	DBLINK_GET_NAMED_CONN;
+	dblink_init();
+	conn = dblink_get_named_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)));
 
 	msg = PQerrorMessage(conn);
 	if (msg == NULL || msg[0] == '\0')
 		PG_RETURN_TEXT_P(cstring_to_text("OK"));
 	else
-		PG_RETURN_TEXT_P(cstring_to_text(msg));
+		PG_RETURN_TEXT_P(cstring_to_text(pchomp(msg)));
 }
 
 /*
@@ -1381,38 +1387,37 @@ dblink_exec(PG_FUNCTION_ARGS)
 	PGconn	   *volatile conn = NULL;
 	volatile bool freeconn = false;
 
-	DBLINK_INIT;
+	dblink_init();
 
 	PG_TRY();
 	{
-		char	   *msg;
 		PGresult   *res = NULL;
-		char	   *connstr = NULL;
 		char	   *sql = NULL;
 		char	   *conname = NULL;
-		remoteConn *rconn = NULL;
 		bool		fail = true;	/* default to backward compatible behavior */
 
 		if (PG_NARGS() == 3)
 		{
 			/* must be text,text,bool */
-			DBLINK_GET_CONN;
+			conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
 			sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
 			fail = PG_GETARG_BOOL(2);
+			dblink_get_conn(conname, &conn, &conname, &freeconn);
 		}
 		else if (PG_NARGS() == 2)
 		{
 			/* might be text,text or text,bool */
 			if (get_fn_expr_argtype(fcinfo->flinfo, 1) == BOOLOID)
 			{
-				conn = pconn->conn;
 				sql = text_to_cstring(PG_GETARG_TEXT_PP(0));
 				fail = PG_GETARG_BOOL(1);
+				conn = pconn->conn;
 			}
 			else
 			{
-				DBLINK_GET_CONN;
+				conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
 				sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
+				dblink_get_conn(conname, &conn, &conname, &freeconn);
 			}
 		}
 		else if (PG_NARGS() == 1)
@@ -1426,14 +1431,15 @@ dblink_exec(PG_FUNCTION_ARGS)
 			elog(ERROR, "wrong number of arguments");
 
 		if (!conn)
-			DBLINK_CONN_NOT_AVAIL;
+			dblink_conn_not_avail(conname);
 
 		res = PQexec(conn, sql);
 		if (!res ||
 			(PQresultStatus(res) != PGRES_COMMAND_OK &&
 			 PQresultStatus(res) != PGRES_TUPLES_OK))
 		{
-			dblink_res_error(conname, res, "could not execute command", fail);
+			dblink_res_error(conn, conname, res,
+							 "could not execute command", fail);
 
 			/*
 			 * and save a copy of the command status string to return as our
@@ -1508,7 +1514,7 @@ dblink_get_pkey(PG_FUNCTION_ARGS)
 		oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
 
 		/* open target relation */
-		rel = get_rel_from_relname(PG_GETARG_TEXT_P(0), AccessShareLock, ACL_SELECT);
+		rel = get_rel_from_relname(PG_GETARG_TEXT_PP(0), AccessShareLock, ACL_SELECT);
 
 		/* get the array of attnums */
 		results = get_pkey_attnames(rel, &numatts);
@@ -1609,7 +1615,7 @@ PG_FUNCTION_INFO_V1(dblink_build_sql_insert);
 Datum
 dblink_build_sql_insert(PG_FUNCTION_ARGS)
 {
-	text	   *relname_text = PG_GETARG_TEXT_P(0);
+	text	   *relname_text = PG_GETARG_TEXT_PP(0);
 	int2vector *pkattnums_arg = (int2vector *) PG_GETARG_POINTER(1);
 	int32		pknumatts_arg = PG_GETARG_INT32(2);
 	ArrayType  *src_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(3);
@@ -1700,7 +1706,7 @@ PG_FUNCTION_INFO_V1(dblink_build_sql_delete);
 Datum
 dblink_build_sql_delete(PG_FUNCTION_ARGS)
 {
-	text	   *relname_text = PG_GETARG_TEXT_P(0);
+	text	   *relname_text = PG_GETARG_TEXT_PP(0);
 	int2vector *pkattnums_arg = (int2vector *) PG_GETARG_POINTER(1);
 	int32		pknumatts_arg = PG_GETARG_INT32(2);
 	ArrayType  *tgt_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(3);
@@ -1777,7 +1783,7 @@ PG_FUNCTION_INFO_V1(dblink_build_sql_update);
 Datum
 dblink_build_sql_update(PG_FUNCTION_ARGS)
 {
-	text	   *relname_text = PG_GETARG_TEXT_P(0);
+	text	   *relname_text = PG_GETARG_TEXT_PP(0);
 	int2vector *pkattnums_arg = (int2vector *) PG_GETARG_POINTER(1);
 	int32		pknumatts_arg = PG_GETARG_INT32(2);
 	ArrayType  *src_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(3);
@@ -1876,9 +1882,7 @@ PG_FUNCTION_INFO_V1(dblink_get_notify);
 Datum
 dblink_get_notify(PG_FUNCTION_ARGS)
 {
-	char	   *conname = NULL;
-	PGconn	   *conn = NULL;
-	remoteConn *rconn = NULL;
+	PGconn	   *conn;
 	PGnotify   *notify;
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
 	TupleDesc	tupdesc;
@@ -1888,9 +1892,9 @@ dblink_get_notify(PG_FUNCTION_ARGS)
 
 	prepTuplestoreResult(fcinfo);
 
-	DBLINK_INIT;
+	dblink_init();
 	if (PG_NARGS() == 1)
-		DBLINK_GET_NAMED_CONN;
+		conn = dblink_get_named_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)));
 	else
 		conn = pconn->conn;
 
@@ -2346,7 +2350,7 @@ quote_ident_cstr(char *rawstr)
 	char	   *result;
 
 	rawstr_text = cstring_to_text(rawstr);
-	result_text = DatumGetTextP(DirectFunctionCall1(quote_ident,
+	result_text = DatumGetTextPP(DirectFunctionCall1(quote_ident,
 											  PointerGetDatum(rawstr_text)));
 	result = text_to_cstring(result_text);
 
@@ -2664,7 +2668,8 @@ dblink_connstr_check(const char *connstr)
 }
 
 static void
-dblink_res_error(const char *conname, PGresult *res, const char *dblink_context_msg, bool fail)
+dblink_res_error(PGconn *conn, const char *conname, PGresult *res,
+				 const char *dblink_context_msg, bool fail)
 {
 	int			level;
 	char	   *pg_diag_sqlstate = PQresultErrorField(res, PG_DIAG_SQLSTATE);
@@ -2693,10 +2698,18 @@ dblink_res_error(const char *conname, PGresult *res, const char *dblink_context_
 	else
 		sqlstate = ERRCODE_CONNECTION_FAILURE;
 
-	xpstrdup(message_primary, pg_diag_message_primary);
-	xpstrdup(message_detail, pg_diag_message_detail);
-	xpstrdup(message_hint, pg_diag_message_hint);
-	xpstrdup(message_context, pg_diag_context);
+	message_primary = xpstrdup(pg_diag_message_primary);
+	message_detail = xpstrdup(pg_diag_message_detail);
+	message_hint = xpstrdup(pg_diag_message_hint);
+	message_context = xpstrdup(pg_diag_context);
+
+	/*
+	 * If we don't get a message from the PGresult, try the PGconn.  This is
+	 * needed because for connection-level failures, PQexec may just return
+	 * NULL, not a PGresult at all.
+	 */
+	if (message_primary == NULL)
+		message_primary = pchomp(PQerrorMessage(conn));
 
 	if (res)
 		PQclear(res);
@@ -2707,7 +2720,7 @@ dblink_res_error(const char *conname, PGresult *res, const char *dblink_context_
 	ereport(level,
 			(errcode(sqlstate),
 			 message_primary ? errmsg_internal("%s", message_primary) :
-			 errmsg("unknown error"),
+			 errmsg("could not obtain message string for remote error"),
 			 message_detail ? errdetail_internal("%s", message_detail) : 0,
 			 message_hint ? errhint("%s", message_hint) : 0,
 			 message_context ? errcontext("%s", message_context) : 0,
@@ -2724,11 +2737,32 @@ get_connect_string(const char *servername)
 	ForeignServer *foreign_server = NULL;
 	UserMapping *user_mapping;
 	ListCell   *cell;
-	StringInfo	buf = makeStringInfo();
+	StringInfoData buf;
 	ForeignDataWrapper *fdw;
 	AclResult	aclresult;
 	char	   *srvname;
 
+	static const PQconninfoOption *options = NULL;
+
+	initStringInfo(&buf);
+
+	/*
+	 * Get list of valid libpq options.
+	 *
+	 * To avoid unnecessary work, we get the list once and use it throughout
+	 * the lifetime of this backend process.  We don't need to care about
+	 * memory context issues, because PQconndefaults allocates with malloc.
+	 */
+	if (!options)
+	{
+		options = PQconndefaults();
+		if (!options)			/* assume reason for failure is OOM */
+			ereport(ERROR,
+					(errcode(ERRCODE_FDW_OUT_OF_MEMORY),
+					 errmsg("out of memory"),
+			 errdetail("could not get libpq's default connection options")));
+	}
+
 	/* first gather the server connstr options */
 	srvname = pstrdup(servername);
 	truncate_identifier(srvname, strlen(srvname), false);
@@ -2752,16 +2786,18 @@ get_connect_string(const char *servername)
 		{
 			DefElem    *def = lfirst(cell);
 
-			appendStringInfo(buf, "%s='%s' ", def->defname,
-							 escape_param_str(strVal(def->arg)));
+			if (is_valid_dblink_option(options, def->defname, ForeignDataWrapperRelationId))
+				appendStringInfo(&buf, "%s='%s' ", def->defname,
+								 escape_param_str(strVal(def->arg)));
 		}
 
 		foreach(cell, foreign_server->options)
 		{
 			DefElem    *def = lfirst(cell);
 
-			appendStringInfo(buf, "%s='%s' ", def->defname,
-							 escape_param_str(strVal(def->arg)));
+			if (is_valid_dblink_option(options, def->defname, ForeignServerRelationId))
+				appendStringInfo(&buf, "%s='%s' ", def->defname,
+								 escape_param_str(strVal(def->arg)));
 		}
 
 		foreach(cell, user_mapping->options)
@@ -2769,11 +2805,12 @@ get_connect_string(const char *servername)
 
 			DefElem    *def = lfirst(cell);
 
-			appendStringInfo(buf, "%s='%s' ", def->defname,
-							 escape_param_str(strVal(def->arg)));
+			if (is_valid_dblink_option(options, def->defname, UserMappingRelationId))
+				appendStringInfo(&buf, "%s='%s' ", def->defname,
+								 escape_param_str(strVal(def->arg)));
 		}
 
-		return buf->data;
+		return buf.data;
 	}
 	else
 		return NULL;
@@ -2788,16 +2825,18 @@ static char *
 escape_param_str(const char *str)
 {
 	const char *cp;
-	StringInfo	buf = makeStringInfo();
+	StringInfoData buf;
+
+	initStringInfo(&buf);
 
 	for (cp = str; *cp; cp++)
 	{
 		if (*cp == '\\' || *cp == '\'')
-			appendStringInfoChar(buf, '\\');
-		appendStringInfoChar(buf, *cp);
+			appendStringInfoChar(&buf, '\\');
+		appendStringInfoChar(&buf, *cp);
 	}
 
-	return buf->data;
+	return buf.data;
 }
 
 /*