我正在使用Percona 5.1.66-14.2。我们的慢速日志配置为记录超过500毫秒（0.5秒）的SQL。
我看到只在慢速日志中设置了timestamp语句。在慢速日志中的SET时间戳之后用分号（;）表示什么吗？
# Time: 130612 2:01:55
# User@Host: root[root] @ localhost []
# Thread_id: 8 Schema: db_cache Last_errno: 0 Killed: 0
# Query_time: 0.667233 Lock_time: 0.000000 Rows_sent: 0 Rows_examined: 0 Rows_affected: 0 Rows_read: 0
# Bytes_sent: 1462 Tmp_tables: 0 Tmp_disk_tables: 0 Tmp_table_sizes: 0
SET timestamp=1371027715;
;
# Time: 130612 2:01:57
# User@Host: root[root] @ localhost []
# Thread_id: 8 Schema: db_cache Last_errno: 0 Killed: 0
# Query_time: 0.524655 Lock_time: 0.000000 Rows_sent: 0 Rows_examined: 0 Rows_affected: 0 Rows_read: 0
# Bytes_sent: 1339 Tmp_tables: 1 Tmp_disk_tables: 0 Tmp_table_sizes: 0
SET timestamp=1371027717;
;
# Time: 130612 2:01:58
# User@Host: root[root] @ localhost []
# Thread_id: 8 Schema: db_cache Last_errno: 0 Killed: 0
# Query_time: 0.775974 Lock_time: 0.000000 Rows_sent: 0 Rows_examined: 0 Rows_affected: 0 Rows_read: 0
# Bytes_sent: 1374 Tmp_tables: 0 Tmp_disk_tables: 0 Tmp_table_sizes: 0
SET timestamp=1371027718;
;
# Time: 130612 2:02:00
# User@Host: root[root] @ localhost []
# Thread_id: 8 Schema: db_cache Last_errno: 0 Killed: 0
# Query_time: 0.986338 Lock_time: 0.000000 Rows_sent: 0 Rows_examined: 0 Rows_affected: 0 Rows_read: 0
# Bytes_sent: 1987 Tmp_tables: 1 Tmp_disk_tables: 0 Tmp_table_sizes: 0
SET timestamp=1371027720;
;**