在给数据库开启慢日志查询的时候遇到 如下问题
root@rac1 : (none) 23:39:53> set global slow_query_log = 1;
ERROR 13 (HY000): Can't get stat of './mysql/slow_log.CSV' (Errcode: 2)
原因是因为数据库中没有slow_log表对应的物理文件，解决的方法有如下两种：
方法一 手工创建slow_log.CSV
[root@rac1 mysql]# touch slow_log.CSV
[root@rac1 mysql]# chown -R mysql:mysql slow_log.CSV
[root@rac1 mysql]# chmod 660 slow_log.CSV
root@rac1 : (none) 23:42:36>set global slow_query_log = 1;
Query OK, 0 rows affected, 1 warning (0.17 sec)
root@rac1 : (none) 23:43:03>show warnings;
+-------+------+--------------------------------------------------------------+
| Level | Code | Message |
+-------+------+--------------------------------------------------------------+
| Error | 1194 | Table 'slow_log' is marked as crashed and should be repaired |
+-------+------+--------------------------------------------------------------+
1 row in set (0.00 sec)
root@rac1 : (none) 23:48:03>repair table mysql.slow_log;
+----------------+--------+----------+----------+
| Table | Op | Msg_type | Msg_text |
+----------------+--------+----------+----------+
| mysql.slow_log | repair | status | OK |
+----------------+--------+----------+----------+
1 row in set (0.61 sec)
root@rac1 : (none) 23:51:03>set global slow_query_log = 1;
Query OK, 0 rows affected (0.00 sec)
方法二 在数据库中以重建表的方式 (个人比较推荐第二种方式)
[root@rac1 ~]# mysql
root@rac1 : (none) 21:47:46>
root@rac1 : (none) 21:47:47> show global variables like '%slow%';
+---------------------+----------------+
| Variable_name | Value |
+---------------------+----------------+
| log_slow_queries | ON |
| slow_launch_time | 2 |
| slow_query_log | ON |
| slow_query_log_file | slow_query.log |
+---------------------+----------------+
4 rows in set (0.06 sec)
root@rac1 : (none) 21:48:19> set global slow_query_log=off;
Query OK, 0 rows affected (0.00 sec)
root@rac1 : (none) 21:48:47>
root@rac1 : (none) 21:48:47> show global variables like '%slow%';
+---------------------+----------------+
| Variable_name | Value |
+---------------------+----------------+
| log_slow_queries | OFF |
| slow_launch_time | 2 |
| slow_query_log | OFF |
| slow_query_log_file | slow_query.log |
+---------------------+----------------+
4 rows in set (0.01 sec)
root@rac1 : (none) 21:48:49> show global variables like '%slow%';
+---------------------+----------------+
| Variable_name | Value |
+---------------------+----------------+
| log_slow_queries | OFF |
| slow_launch_time | 2 |
| slow_query_log | OFF |
| slow_query_log_file | slow_query.log |
+---------------------+----------------+
4 rows in set (0.00 sec)
root@rac1 : (none) 21:49:50> set global slow_query_log=on;
ERROR 13 (HY000): Can't get stat of './mysql/slow_log.CSV' (Errcode: 2)
root@rac1 : mysql 21:50:33> show create table slow_log;
ERROR 13 (HY000): Can't get stat of './mysql/slow_log.CSV' (Errcode: 2)
从一个有slow_log 的数据库中查看slow_log的表创建ddl 语句，进行创建！
root@rac1 : mysql 21:51:23> CREATE TABLE `slow_log` (
-> `start_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
-> `user_host` mediumtext NOT NULL,
-> `query_time` time NOT NULL,
-> `lock_time` time NOT NULL,
-> `rows_sent` int(11) NOT NULL,
-> `rows_examined` int(11) NOT NULL,
-> `db` varchar(512) NOT NULL,
-> `last_insert_id` int(11) NOT NULL,
-> `insert_id` int(11) NOT NULL,
-> `server_id` int(10) unsigned NOT NULL,
-> `sql_text` mediumtext NOT NULL
-> ) ENGINE=MyISAM DEFAULT CHARSET=utf8 COMMENT='Slow log';
Query OK, 0 rows affected (0.04 sec)
root@rac1 : mysql 21:51:43>
root@rac1 : mysql 21:51:55> set global slow_query_log=on;
Query OK, 0 rows affected (0.00 sec)
root@rac1 : mysql 21:52:13>
root@rac1 : mysql 21:52:13> show global variables like '%out%';
+----------------------------+----------+
| Variable_name | Value |
+----------------------------+----------+
| log_output | FILE |
+----------------------------+----------+
11 rows in set (0.00 sec)
root@rac1 : mysql 21:52:20> set global log_output = 'TABLE';
Query OK, 0 rows affected (0.00 sec)
root@rac1 : mysql 21:52:41> show global variables like '%out%';
+----------------------------+----------+
| Variable_name | Value |
+----------------------------+----------+
| log_output | TABLE |
+----------------------------+----------+
11 rows in set (0.00 sec)
如果log_output 用TABLE形式记录日志，mysql会以表的形式将slow_log存入mysql表中的slow_log表中。
root@rac1 : mysql 21:52:43> select sleep(60);
+-----------+
| sleep(60) |
+-----------+
| 0 |
+-----------+
1 row in set (1 min 0.00 sec)
root@rac1 : mysql 21:54:01> select * from slow_log \G
*************************** 1. row ***************************
start_time: 2012-08-24 21:54:01
user_host: root[root] @ localhost [127.0.0.1]
query_time: 00:01:00
lock_time: 00:00:00
rows_sent: 1
rows_examined: 0
db: mysql
last_insert_id: 0
insert_id: 0
server_id: 1
sql_text: select sleep(60)
1 row in set (0.00 sec)
root@rac1 : mysql 21:57:53>
root@rac1 : mysql 21:58:25> set global log_output = 'FILE';
Query OK, 0 rows affected (0.00 sec)
root@rac1 : mysql 21:58:30> select sleep(10);
+-----------+
| sleep(10) |
+-----------+
| 0 |
+-----------+
1 row in set (10.00 sec)
由于log_output 用FILE形式记录日志，所以我们在vim /home/mysql/log/mysql-slow.log 将会看到执行超过0秒的所有的sql
-bash-3.2$ tail -f slow_query.log
Tcp port: 3306 Unix socket: /tmp/mysql.sock
Time Id Command Argument
# Time: 120824 21:58:48
# User@Host: root[root] @ localhost [127.0.0.1]
# Query_time: 10.001827 Lock_time: 0.000000 Rows_sent: 1 Rows_examined: 0
use mysql;
SET timestamp=1345816728;
select sleep(10);
至此问题完全得到解决。