Mysql 数据库常用配置命令
1.查看mysql数据库默认编码:
mysql> show variables like "character%";
+--------------------------+----------------------------+
| Variable_name | Value |
+--------------------------+----------------------------+
| character_set_client | utf8 |
| character_set_connection | utf8 |
| character_set_database | utf8 |
| character_set_filesystem | binary |
| character_set_results | utf8 |
| character_set_server | utf8 |
| character_set_system | utf8 |
| character_sets_dir | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+
8 rows in set (0.00 sec)
2.开启Mysql数据库慢查询和binlog日志功能
1)开启慢查询日志，找到my.cnf，添加如下内容 vim /usr/local/mysql/my.cnf
然后重启mysql服务：systemctl restart mysqld
查看慢查询日志是否开启：
mysql> show variables like 'slow_query_log';
+----------------+-------+
| Variable_name | Value |
+----------------+-------+
| slow_query_log | ON |
+----------------+-------+
1 row in set (0.03 sec)
mysql> show variables like '%quer%';
+----------------------------------------+---------------------+
| Variable_name | Value |
+----------------------------------------+---------------------+
| binlog_rows_query_log_events | OFF |
| ft_query_expansion_limit | 20 |
| have_query_cache | YES |
| log_queries_not_using_indexes | ON |
| log_throttle_queries_not_using_indexes | 0 |
| long_query_time | 1.000000 |
| query_alloc_block_size | 8192 |
| query_cache_limit | 1048576 |
| query_cache_min_res_unit | 4096 |
| query_cache_size | 1048576 |
| query_cache_type | OFF |
| query_cache_wlock_invalidate | OFF |
| query_prealloc_size | 8192 |
| slow_query_log | ON |
| slow_query_log_file | /tmp/mysql-slow.log |
+----------------------------------------+---------------------+
15 rows in set (0.00 sec)
如上所示：已经开启了慢查询日志！
注意：如果更改日志目录位置
比如，更改为/home/msyql/log/mysql-slow.log
至少需要将log目录所有者设置为mysql:mysql。
这样重启mysql的时候，才能自动生成mysql-slow.log文件。
如果log目录不是mysql用户权限，将无法生成日志文件，mysql用户无权写入数据。
2)bin-log日志开启, 必须设置server-id.
保存退出，重启mysql服务：systemctl restart mysqld
查看 logbin是否开启：
mysql> show variables like "%log_bin%";
+---------------------------------+--------------------------------+
| Variable_name | Value |
+---------------------------------+--------------------------------+
| log_bin | ON |
| log_bin_basename | /var/lib/mysql/mysql-bin |
| log_bin_index | /var/lib/mysql/mysql-bin.index |
| log_bin_trust_function_creators | OFF |
| log_bin_use_v1_row_events | OFF |
| sql_log_bin | ON |
+---------------------------------+--------------------------------+
6 rows in set (0.01 sec)
如上所示binlog已经开启！
