This commit fixes potential coordinator crash if no GTM connection

is established.

Posted by Wang Diancheng.   Reviewed by Koichi Suzuki.

Author: koichi-szk

src/backend/access/transam/gtm.c

@@ -170,12 +170,13 @@ BeginTranAutovacuumGTM(void)
 int
 CommitTranGTM(GlobalTransactionId gxid)
 {
-	int ret;
+	int ret = -1;
 
 	if (!GlobalTransactionIdIsValid(gxid))
 		return 0;
 	CheckConnection();
-	ret = commit_transaction(conn, gxid);
+	if (conn)
+		ret = commit_transaction(conn, gxid);
 
 	/*
 	 * If something went wrong (timeout), try and reset GTM connection.
@@ -203,12 +204,13 @@ CommitTranGTM(GlobalTransactionId gxid)
 int
 CommitPreparedTranGTM(GlobalTransactionId gxid, GlobalTransactionId prepared_gxid)
 {
-	int ret = 0;
+	int ret = -1;
 
 	if (!GlobalTransactionIdIsValid(gxid) || !GlobalTransactionIdIsValid(prepared_gxid))
 		return ret;
 	CheckConnection();
-	ret = commit_prepared_transaction(conn, gxid, prepared_gxid);
+	if (conn)
+		ret = commit_prepared_transaction(conn, gxid, prepared_gxid);
 
 	/*
 	 * If something went wrong (timeout), try and reset GTM connection.
@@ -257,13 +259,14 @@ StartPreparedTranGTM(GlobalTransactionId gxid,
 					 char *gid,
 					 char *nodestring)
 {
-	int ret = 0;
+	int ret = -1;
 
 	if (!GlobalTransactionIdIsValid(gxid))
 		return 0;
 	CheckConnection();
 
-	ret = start_prepared_transaction(conn, gxid, gid, nodestring);
+	if (conn)
+		ret = start_prepared_transaction(conn, gxid, gid, nodestring);
 
 	/*
 	 * If something went wrong (timeout), try and reset GTM connection.
@@ -282,12 +285,13 @@ StartPreparedTranGTM(GlobalTransactionId gxid,
 int
 PrepareTranGTM(GlobalTransactionId gxid)
 {
-	int ret;
+	int ret = -1;
 
 	if (!GlobalTransactionIdIsValid(gxid))
 		return 0;
 	CheckConnection();
-	ret = prepare_transaction(conn, gxid);
+	if (conn)
+		ret = prepare_transaction(conn, gxid);
 
 	/*
 	 * If something went wrong (timeout), try and reset GTM connection.
@@ -310,11 +314,12 @@ GetGIDDataGTM(char *gid,
 			  GlobalTransactionId *prepared_gxid,
 			  char **nodestring)
 {
-	int ret = 0;
+	int ret = -1;
 
 	CheckConnection();
-	ret = get_gid_data(conn, GTM_ISOLATION_RC, gid, gxid,
-					   prepared_gxid, nodestring);
+	if (conn)
+		ret = get_gid_data(conn, GTM_ISOLATION_RC, gid, gxid,
+						   prepared_gxid, nodestring);
 
 	/*
 	 * If something went wrong (timeout), try and reset GTM connection.