innodb_buffer_pool_size 物理内存的 50%-80%
innodb_buffer_pool_instances （innodb_buffer_pool_size（G）/1） 每个实例建议至少 1GB
innodb_file_per_table=ON
slow_query_log=ON
slow_query_log_file = /var/lib/mysql/mysql-slow.log
long_query_time=3
max_allowed_packet=64M

query_cache_size=100M
sort_buffer_size=40M
read_buffer_size=40M