语法: keys = ngx.shared.DICT:get_keys(max_count?)
环境: init_by_lua*, set_by_lua*, rewrite_by_lua*, access_by_lua*, content_by_lua*, header_filter_by_lua*, body_filter_by_lua*, log_by_lua*, ngx.timer.*
获取字典中存储的 key 列表，最多 <max_count> 个。
默认时，前 1024 个 key (如果有) 被返回。当参数 <max_count> 值为 0 时，字典中所有的 key 被返回，即使超过 1024 个。
警告 在包含非常多 key 的字典中调用此方法要非常小心。此方法会锁定字典一段时间，会阻塞所有访问字典的 nginx worker 进程。
这个功能最早出现在 v0.7.3 版本中。
English Source
syntax: keys = ngx.shared.DICT:get_keys(max_count?)
context: init_by_lua*, set_by_lua*, rewrite_by_lua*, access_by_lua*, content_by_lua*, header_filter_by_lua*, body_filter_by_lua*, log_by_lua*, ngx.timer.*
Fetch a list of the keys from the dictionary, up to <max_count>.
By default, only the first 1024 keys (if any) are returned. When the <max_count> argument is given the value 0, then all the keys will be returned even there is more than 1024 keys in the dictionary.
WARNING Be careful when calling this method on dictionaries with a really huge number of keys. This method may lock the dictionary for quite a while and block all the nginx worker processes that are trying to access the dictionary.
This feature was first introduced in the v0.7.3 release.