Enable slow_query_log tries to write to slow_log.CSV I'm running MySQL 5.5

I wanted to truncate the slow log file, so I did:

SET GLOBAL slow_query_log = 0;


then truncated the file in filesystem.

But, when I enable it back it fails:

SET GLOBAL slow_query_log = 1;
ERROR 13 (HY000): Can't get stat of './mysql/slow_log.CSV' (Errcode: 2)


Although the slow_query_log_file set explicitly to another path.

SHOW GLOBAL VARIABLES LIKE 'slow_query%';
+------------------------------------+---------------------------------+
| Variable_name                      | Value                           |
+------------------------------------+---------------------------------+
| slow_query_log                     | OFF                             |
| slow_query_log_file                | /home/mysql_data/jobs1-slow.log |
| slow_query_log_timestamp_always    | OFF                             |
| slow_query_log_timestamp_precision | second                          |
| slow_query_log_use_global_control  |                                 |
+------------------------------------+---------------------------------+


What is wrong? I want MySQL log to the specified file. Plain text, not CSV.

SHOW GLOBAL VARIABLES LIKE 'log_output';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| log_output    | FILE  |
+---------------+-------+


Before I stopped it logging was fine.
I did these steps :


set global slow_query_log=0;
remove the slow log file in system
set global slow_query_log=1;


it works fine, so I tried these steps:

mysql&gt; set global slow_query_log=0;
Query OK, 0 rows affected (0.12 sec)

mysql&gt; set global slow_query_log_file='/tmp/slow.log';
Query OK, 0 rows affected (0.10 sec)

mysql&gt; set global slow_query_log=1;
Query OK, 0 rows affected (0.00 sec)


still works, and new slow log file is generated as /tmp/slow.log.

At last, the value of global variable log_output decides where to generate the general log and slow log's output, not the file format.