docker 中mysql 5.6 内存占用过大，优化配置

主要参考 https://blog.csdn.net/nagisazz/article/details/86540992
https://v2ex.com/t/269589
https://blog.csdn.net/kangle0228/article/details/81334555

经过多次尝试后，我的mysql的内存占用从500M上下，减少到了80M上下

最后我自己的使用的配置如下

[client]
port                    = 3306
default-character-set   = utf8mb4


[mysqld]
user                    = mysql
port                    = 3306
sql_mode                = ""

############# mysql性能配置 ######################
#sql_mode        = NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION
key_buffer_size     = 200M
tmp-table-size      = 32M
table_open_cache    = 128
table_definition_cache  = 200
query_cache_size    = 32M
query_cache_limit   = 1M
query_cache_min_res_unit= 2k
max_allowed_packet  = 20M



#####与线程有关的配置
thread_concurrency  = 8
thread_cache_size   = 64
sort_buffer_size    = 2M
read_buffer_size    = 2M
read_rnd_buffer_size    = 2M
join_buffer_size    = 2M
#####per