diff --git a/src/protocol/mysql_byteorder.c b/src/protocol/mysql_byteorder.c
index 47de046d..7b8b0c4d 100644
--- a/src/protocol/mysql_byteorder.c
+++ b/src/protocol/mysql_byteorder.c
@@ -58,6 +58,9 @@ int decode_length_safe(unsigned long long *res, const unsigned char **pos,
 		*res = uint8korr(p + 1);
 		*pos = p + 9;
 		break;
+
+	case 255:
+		return -1;
 	}
 
 	return 1;
@@ -68,7 +71,7 @@ int decode_string(const unsigned char **str, unsigned long long *len,
 {
 	unsigned long long length;
 
-	if (decode_length_safe(&length, pos, end) == 0)
+	if (decode_length_safe(&length, pos, end) <= 0)
 		return 0;
 
 	if (length == 0 || length == (~0ULL))
diff --git a/src/protocol/mysql_parser.c b/src/protocol/mysql_parser.c
index 48b6ebe6..187a4c21 100644
--- a/src/protocol/mysql_parser.c
+++ b/src/protocol/mysql_parser.c
@@ -182,10 +182,10 @@ static int parse_ok_packet(const void *buf, size_t len, mysql_parser_t *parser)
 	int ret;
 
 	p += 1;// 0x00
-	if (decode_length_safe(&affected_rows, &p, buf_end) == 0)
+	if (decode_length_safe(&affected_rows, &p, buf_end) <= 0)
 		return -2;
 
-	if (decode_length_safe(&insert_id, &p, buf_end) == 0)
+	if (decode_length_safe(&insert_id, &p, buf_end) <= 0)
 		return -2;
 
 	if (p + 4 > buf_end)
@@ -199,10 +199,20 @@ static int parse_ok_packet(const void *buf, size_t len, mysql_parser_t *parser)
 	if (p < buf_end)
 	{
 		ret = decode_length_safe(&info_len, &p, buf_end);
-		info_len = (info_len == (unsigned long long)-1) ? 0 : info_len;
-		if (ret == 0 || p + info_len > buf_end)
+		if (ret > 0)
+		{
+			if (info_len == ~0ULL)
+				info_len = 0;
+			if (p + info_len > buf_end)
+				return -2;
+		}
+		else if (ret < 0)
+			info_len = 0;
+		else
 			return -2;
+
 	} else {
+		ret = 1;
 		info_len = 0;
 	}
 
@@ -212,9 +222,8 @@ static int parse_ok_packet(const void *buf, size_t len, mysql_parser_t *parser)
 
 	result_set->info_offset = p - (const unsigned char *)buf;
 	result_set->info_len = info_len;
-	result_set->affected_rows = (affected_rows == (unsigned long long)-1) ?
-											   0 : affected_rows;
-	result_set->insert_id = (insert_id == (unsigned long long)-1) ? 0 : insert_id;
+	result_set->affected_rows = (affected_rows == ~0ULL) ? 0 : affected_rows;
+	result_set->insert_id = (insert_id == ~0ULL) ? 0 : insert_id;
 	result_set->server_status = server_status;
 	result_set->warning_count = warning_count;
 	result_set->type = MYSQL_PACKET_OK;
@@ -228,6 +237,12 @@ static int parse_ok_packet(const void *buf, size_t len, mysql_parser_t *parser)
 	parser->buf = buf;
 	parser->offset = result_set->info_offset + result_set->info_len;
 
+	if (ret < 0)
+	{
+		parser->parse = parse_error_packet;
+		return 0;
+	}
+
 	if (server_status & MYSQL_SERVER_MORE_RESULTS_EXIST)
 	{
 		parser->parse = parse_base_packet;
@@ -337,13 +352,11 @@ static int parse_field_count(const void *buf, size_t len, mysql_parser_t *parser
 
 	unsigned long long field_count;
 	struct __mysql_result_set *result_set;
-	int ret;
 
-	ret = decode_length_safe(&field_count, &p, buf_end);
-	if (ret == 0)
+	if (decode_length_safe(&field_count, &p, buf_end) <= 0)
 		return -2;
 
-	field_count = (field_count == (unsigned long long)-1) ? 0 : field_count;
+	field_count = (field_count == ~0ULL) ? 0 : field_count;
 
 	if (field_count)
 	{
diff --git a/src/protocol/mysql_parser.h b/src/protocol/mysql_parser.h
index 6f0cb9f1..ba92ecac 100644
--- a/src/protocol/mysql_parser.h
+++ b/src/protocol/mysql_parser.h
@@ -63,25 +63,18 @@ struct __mysql_result_set
 	struct list_head list;
 	int type;
 	int server_status;
-	union
-	{
-		struct
-		{
-			int field_count;
-			int row_count;
-			size_t rows_begin_offset;
-			size_t rows_end_offset;
-			mysql_field_t **fields;
-		};
-		struct
-		{
-			unsigned long long affected_rows;
-			unsigned long long insert_id;
-			int warning_count;
-			size_t info_offset;
-			int info_len;
-		};
-	};
+
+	int field_count;
+	int row_count;
+	size_t rows_begin_offset;
+	size_t rows_end_offset;
+	mysql_field_t **fields;
+
+	unsigned long long affected_rows;
+	unsigned long long insert_id;
+	int warning_count;
+	size_t info_offset;
+	int info_len;
 };
 
 typedef struct __mysql_result_set_cursor 
diff --git a/tutorial/tutorial-12-mysql_cli.cc b/tutorial/tutorial-12-mysql_cli.cc
index 2ed4c930..20504696 100644
--- a/tutorial/tutorial-12-mysql_cli.cc
+++ b/tutorial/tutorial-12-mysql_cli.cc
@@ -183,7 +183,7 @@ void mysql_callback(WFMySQLTask *task)
 				fprintf(stderr, "  __________ ROW END __________\n");
 			}
 		}
-		else if (cursor.get_cursor_status() == MYSQL_PACKET_OK)
+		else if (cursor.get_cursor_status() == MYSQL_STATUS_OK)
 		{
 			fprintf(stderr, "  OK. %llu ", cursor.get_affected_rows());
 			if (cursor.get_affected_rows() == 1)