lua_code_cache设置成off导致init_by_lua_block是每个请求执行一遍

[chnliyong]

https://github.com/openresty/lua-nginx-module#init_by_lua

In case that the lua_code_cache directive is turned off (default on), the init_by_lua handler will run upon every request because in this special mode a standalone Lua VM is always created for each request.

[dealernomore]

开发环境时用的配置，线上环境是要打开cache的。
我修改备注一下。