Replace the function is_supported_version() with the function pg_version()

the main difference is that this new function doesn't return a bool but
a string representing the current major version of the postgresql server
or an empty string if it's earlier than 9.0.
Teach all commands that could connect to master and standby that they
both should have the same major version.

dbutils.c

@@ -56,13 +56,21 @@ is_standby(PGconn *conn)
 }
 
 
-bool
-is_supported_version(PGconn *conn)
+/* 
+ * If postgreSQL version is 9 or superior returns the major version
+ * if 8 or inferior returns an empty string
+ */
+char *
+pg_version(PGconn *conn)
 {
 	PGresult	*res;
-	int			major_version;
+	char		*major_version;
 
-    res = PQexec(conn, "SELECT split_part(split_part(version(), ' ', 2), '.', 1)");
+	int			major_version1;
+	char		*major_version2;
+
+    res = PQexec(conn, "WITH pg_version(ver) AS (SELECT split_part(version(), ' ', 2)) "
+                       "SELECT split_part(ver, '.', 1), split_part(ver, '.', 2) FROM pg_version");
     if (PQresultStatus(res) != PGRES_TUPLES_OK)
     {
 		fprintf(stderr, "PQexec failed: %s", PQerrorMessage(conn));
@@ -70,10 +78,20 @@ is_supported_version(PGconn *conn)
 		PQfinish(conn);
 		exit(1);
     }
-    major_version = atoi(PQgetvalue(res, 0, 0));
+    major_version1 = atoi(PQgetvalue(res, 0, 0));
+    major_version2 = PQgetvalue(res, 0, 1);
     PQclear(res);
 
-	return (major_version >= 9) ? true : false;
+	major_version = malloc(10);
+	if (major_version1 >= 9)
+	{
+		/* form a major version string */
+		sprintf(major_version, "%d.%s", major_version1, major_version2);
+	}
+	else
+		strcpy(major_version, "");
+
+	return major_version;
 }
 
 

dbutils.h

@@ -6,7 +6,7 @@
 
 PGconn *establishDBConnection(const char *conninfo, const bool exit_on_error);
 bool    is_standby(PGconn *conn);
-bool 	is_supported_version(PGconn *conn);
+char   *pg_version(PGconn *conn);
 bool 	guc_setted(PGconn *conn, const char *parameter, const char *op, const char *value);
 const char   *get_cluster_size(PGconn *conn);
 PGconn * getMasterConnection(PGconn *standby_conn, int id, char *cluster, int *master_id);

repmgr.c

@@ -269,6 +269,7 @@ do_master_register(void)
     char 		conninfo[MAXLEN]; 
 
 	bool		schema_exists = false;
+	const char *master_version = NULL;
 
 	/*
 	 * Read the configuration file: repmgr.conf
@@ -283,6 +284,15 @@ do_master_register(void)
 
     conn = establishDBConnection(conninfo, true);
 
+	/* master should be v9 or better */
+	master_version = pg_version(conn);
+	if (strcmp(master_version, "") == 0)
+	{
+		PQfinish(conn);
+		fprintf(stderr, _("%s needs master to be PostgreSQL 9.0 or better\n"), progname); 
+		return;
+	}
+
 	/* Check we are a master */
 	if (is_standby(conn))
 	{
@@ -436,6 +446,9 @@ do_standby_register(void)
 	int     	myLocalId   = -1;
     char 		conninfo[MAXLEN]; 
 
+	const char	*master_version = NULL;
+	const char	*standby_version = NULL;
+
 	/*
 	 * Read the configuration file: repmgr.conf
      */
@@ -449,6 +462,15 @@ do_standby_register(void)
 
     conn = establishDBConnection(conninfo, true);
 
+	/* should be v9 or better */
+	standby_version = pg_version(conn);
+	if (strcmp(standby_version, "") == 0)
+	{
+		PQfinish(conn);
+		fprintf(stderr, _("%s needs standby to be PostgreSQL 9.0 or better\n"), progname); 
+		return;
+	}
+
 	/* Check we are a standby */
 	if (!is_standby(conn))
 	{
@@ -482,6 +504,27 @@ do_standby_register(void)
 	if (!master_conn)
 		return;
 
+	/* master should be v9 or better */
+	master_version = pg_version(master_conn);
+	if (strcmp(master_version, "") == 0)
+	{
+		PQfinish(conn);
+		PQfinish(master_conn);
+		fprintf(stderr, _("%s needs master to be PostgreSQL 9.0 or better\n"), progname); 
+		return;
+	}
+
+	/* master and standby version should match */
+	if (strcmp(master_version, standby_version) == 0)
+	{
+		PQfinish(conn);
+		PQfinish(master_conn);
+		fprintf(stderr, _("%s needs versions of both master (%s) and standby (%s) to match.\n"), 
+				progname, master_version, standby_version); 
+		return;
+	}
+
+
 	/* Now register the standby */
 	if (force)
 	{
@@ -517,6 +560,7 @@ do_standby_register(void)
 	return;
 }
 
+
 static void 
 do_standby_clone(void)
 {
@@ -538,6 +582,8 @@ do_standby_clone(void)
 	const char	*first_wal_segment = NULL; 
     const char	*last_wal_segment = NULL;
 
+	const char	*master_version = NULL;
+
 	/* if dest_dir hasn't been provided, initialize to current directory */
 	if (dest_dir == NULL)
 	{
@@ -619,10 +665,11 @@ do_standby_clone(void)
     }
 
 	/* primary should be v9 or better */
-	if (!is_supported_version(conn))
+	master_version = pg_version(conn);
+	if (strcmp(master_version, "") == 0)
 	{
 		PQfinish(conn);
-		fprintf(stderr, _("%s needs PostgreSQL 9.0 or better\n"), progname); 
+		fprintf(stderr, _("%s needs master to be PostgreSQL 9.0 or better\n"), progname); 
 		return;
 	}
 
@@ -903,6 +950,8 @@ do_standby_promote(void)
 	char		recovery_file_path[MAXLEN];
 	char		recovery_done_path[MAXLEN];
 
+	const char	*standby_version = NULL;
+
 	/*
 	 * Read the configuration file: repmgr.conf
      */
@@ -917,10 +966,12 @@ do_standby_promote(void)
 	/* We need to connect to check configuration */
     conn = establishDBConnection(conninfo, true);
 
-	if (!is_supported_version(conn))
+	/* we need v9 or better */
+	standby_version = pg_version(conn);
+	if (strcmp(standby_version, "") == 0)
 	{
 		PQfinish(conn);
-		fprintf(stderr, _("%s needs PostgreSQL 9.0 or better\n"), progname); 
+		fprintf(stderr, _("%s needs standby to be PostgreSQL 9.0 or better\n"), progname); 
 		return;
 	}
 
@@ -993,6 +1044,9 @@ do_standby_follow(void)
 	int			r;
 	char		data_dir[MAXLEN];
 
+	const char	*master_version = NULL;
+	const char	*standby_version = NULL;
+
 	/*
 	 * Read the configuration file: repmgr.conf
      */
@@ -1015,10 +1069,11 @@ do_standby_follow(void)
 	}
 
 	/* should be v9 or better */
-	if (!is_supported_version(conn))
+	standby_version = pg_version(conn);
+	if (strcmp(standby_version, "") == 0)
 	{
 		PQfinish(conn);
-		fprintf(stderr, _("\n%s needs PostgreSQL 9.0 or better\n"), progname); 
+		fprintf(stderr, _("\n%s needs standby to be PostgreSQL 9.0 or better\n"), progname); 
 		return;
 	}
 
@@ -1040,13 +1095,25 @@ do_standby_follow(void)
 	}
 
 	/* should be v9 or better */
-	if (!is_supported_version(master_conn))
+	master_version = pg_version(master_conn);
+	if (strcmp(master_version, "") == 0)
 	{
 		PQfinish(conn);
 		PQfinish(master_conn);
-		fprintf(stderr, _("%s needs PostgreSQL 9.0 or better\n"), progname); 
+		fprintf(stderr, _("%s needs master to be PostgreSQL 9.0 or better\n"), progname); 
 		return;
 	}
+
+	/* master and standby version should match */
+	if (strcmp(master_version, standby_version) == 0)
+	{
+		PQfinish(conn);
+		PQfinish(master_conn);
+		fprintf(stderr, _("%s needs versions of both master (%s) and standby (%s) to match.\n"), 
+				progname, master_version, standby_version); 
+		return;
+	}
+
 	PQfinish(master_conn);
 
 	if (verbose)

repmgrd.c

@@ -81,6 +81,7 @@ main(int argc, char **argv)
 	int			c;
 
     char conninfo[MAXLEN]; 
+	const char	*standby_version = NULL;
 
 	progname = get_progname(argv[0]);
 
@@ -136,6 +137,15 @@ main(int argc, char **argv)
 
     myLocalConn = establishDBConnection(conninfo, true);
 
+	/* should be v9 or better */
+	standby_version = pg_version(myLocalConn);
+	if (strcmp(standby_version, "") == 0)
+	{
+		PQfinish(myLocalConn);
+		fprintf(stderr, _("%s needs standby to be PostgreSQL 9.0 or better\n"), progname); 
+		exit(1);
+	}
+
     /*
      * Set my server mode, establish a connection to primary
 	 * and start monitor