Comment 2 for bug 1617451

I tried with Percona Server 5.5.55 via yum install on debian wheezy and I found really strange behavior.

mysql> show global variables like '%version%';
+-------------------------+------------------------------------------------------+
| Variable_name | Value |
+-------------------------+------------------------------------------------------+
| innodb_version | 5.5.55-38.8 |
| protocol_version | 10 |
| slave_type_conversions | |
| tls_version | TLSv1.1,TLSv1.2 |
| version | 5.5.55-38.8-log |
| version_comment | Percona Server (GPL), Release 38.8, Revision 11f5bbd |
| version_compile_machine | x86_64 |
| version_compile_os | debian-linux-gnu |
+-------------------------+------------------------------------------------------+

I un-commented below line from default my.cnf

log_slow_queries = /var/log/mysql/mysql-slow.log

After Percona Server restart

mysql> show global variables like '%slow%';
+------------------------------------+-------------------------------+
| Variable_name | Value |
+------------------------------------+-------------------------------+
| log_slow_admin_statements | OFF |
| log_slow_filter | |
| log_slow_queries | ON |
| log_slow_rate_limit | 1 |
| log_slow_rate_type | session |
| log_slow_slave_statements | OFF |
| log_slow_sp_statements | ON |
| log_slow_verbosity | |
| max_slowlog_files | 0 |
| max_slowlog_size | 0 |
| slow_launch_time | 2 |
| slow_query_log | ON |
| slow_query_log_always_write_time | 10.000000 |
| slow_query_log_file | /var/log/mysql/mysql-slow.log |
| slow_query_log_timestamp_always | OFF |
| slow_query_log_timestamp_precision | second |
| slow_query_log_use_global_control | |
+------------------------------------+-------------------------------+
17 rows in set (0.00 sec)

Slow query log enabled despite of it's disabled from slow log. Further, log_slow_queries should accept ON|OFF bit instead showing value for slow_query_log_file. Other than that, log_slow_queries should be removed completely as slow_query_log is the correct parameter to enable slow log. I'm going to open new bug report for this and this is true for upstream too.

Despite of all those MySQL server restart should be failing as monitored in version 5.6 for deprecated variable log_slow_queries