Index: src/libs/zbxdb/db.c
===================================================================
--- src/libs/zbxdb/db.c	(revision 41871)
+++ src/libs/zbxdb/db.c	(working copy)
@@ -359,6 +359,8 @@
 	{
 		zabbix_errlog(ERR_Z3001, dbname, 0, PQerrorMessage(conn));
 		ret = ZBX_DB_DOWN;
+
+		zbx_db_close();
 	}
 	else
 	{
@@ -366,23 +368,23 @@
 		if (NULL != (row = DBfetch(result)))
 			ZBX_PG_BYTEAOID = atoi(row[0]);
 		DBfree_result(result);
-	}
 
-	ZBX_PG_SVERSION = PQserverVersion(conn);
-	zabbix_log(LOG_LEVEL_DEBUG, "PostgreSQL Server version: %d", ZBX_PG_SVERSION);
+		ZBX_PG_SVERSION = PQserverVersion(conn);
+		zabbix_log(LOG_LEVEL_DEBUG, "PostgreSQL Server version: %d", ZBX_PG_SVERSION);
 
-	/* disable "nonstandard use of \' in a string literal" warning */
-	DBexecute("set escape_string_warning to off");
+		/* disable "nonstandard use of \' in a string literal" warning */
+		DBexecute("set escape_string_warning to off");
 
-	result = DBselect("show standard_conforming_strings");
-	if (NULL != (row = DBfetch(result)))
-		ZBX_PG_ESCAPE_BACKSLASH = (0 == strcmp(row[0], "off"));
-	DBfree_result(result);
+		result = DBselect("show standard_conforming_strings");
+		if (NULL != (row = DBfetch(result)))
+			ZBX_PG_ESCAPE_BACKSLASH = (0 == strcmp(row[0], "off"));
+		DBfree_result(result);
 
-	if (90000 <= ZBX_PG_SVERSION)
-	{
-		/* change the output format for values of type bytea from hex (the default) to escape */
-		DBexecute("set bytea_output=escape");
+		if (90000 <= ZBX_PG_SVERSION)
+		{
+			/* change the output format for values of type bytea from hex (the default) to escape */
+			DBexecute("set bytea_output=escape");
+		}
 	}
 #elif defined(HAVE_SQLITE3)
 #ifdef HAVE_FUNCTION_SQLITE3_OPEN_V2
@@ -512,8 +514,11 @@
 		oracle.srvhp = NULL;
 	}
 #elif defined(HAVE_POSTGRESQL)
-	PQfinish(conn);
-	conn = NULL;
+	if (NULL != conn)
+	{
+		PQfinish(conn);
+		conn = NULL;
+	}
 #elif defined(HAVE_SQLITE3)
 	sqlite3_close(conn);
 	conn = NULL;