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Repair table in MySQL
Answer:
If you are using the MyISAM storage engine, database might be corrupted when the computer was shutdown unexpectedly. To repair the table, you can use the following command in the MySQL client.
mysql> REPAIR TABLE my_table;
Change MySQL replication master host
Answer:
To change the MySQL replication master host from a MySQL slave, follow the steps below.
1. Copy current master bin log file name and position
mysql> STOP SLAVE;
mysql> SHOW SLAVE STATUS\G
You will find something like the following...
Master_Log_File: mysql-bin.000081
Read_Master_Log_Pos: 3684056824
2. Change to new master using command
mysql> CHANGE MASTER TO MASTER_HOST='192.168.1.2', MASTER_LOG_FILE='mysql-bin.000081', MASTER_LOG_POS=3684056824;
mysql> START SLAVE;
Flush all MySQL log files
Answer:
MySQL default has several log files such as the error log, query log, and slow query log.
Sometimes, To perform log rotation, it is necessary to tell MySQL stop writing to these old log files, rename it and start over again.
To do so, you can execute the FLUSH LOG command in the MySQL client.
mysql> FLUSH LOG;
As a result, it will causes the MySQL to rename the current error log file with a suffix of -old and create a new empty log file.
Usually you should no need to do it manually, you should use tool such as logrotate .
Reference: http://dev.mysql.com/doc/refman/5.0/en/flush.html
Copy existing table schema to a new table
Answer:
To copy the table schema of an existing table to a new table, without copying its data:
mysql> CREATE TABLE new_table LIKE old_table;
Turn off InnoDB support in MySQL
Answer:
If you never use the InnoDB storage engine in MySQL, it is better to disable it.
To disable this feature, edit the MySQL configurations, e.g. /etc/my.cnf
[mysqld]
...
...
skip-innodb
Add the "skip-innodb" will do the tricks for you.
Don't forget to restart MySQL to take effect.
# /sbin/service mysqld restart
