percona-toolkit OPTIMIZE TABLE

1. MySQL查看剩余空间

select table_name,
round(data_length/1024/1024) as data_length_mb, 
round(data_free/1024/1024) as data_free_mb 
 from information_schema.tables 
 where table_name in 
 ( 'EMPLOYEE', 'DEPARTMENT', 'BENEFITS' );