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Stuff Goes Bad:Erlang In Anger

OTP Processes

When processes in question are OTP processes (most of the processes in a production system should definitely be OTP processes), you instantly win more tools to inspect them.  In general the sys module 23 is what you want to look into. Read the documentation
on it and you’ll discover why it’s so useful. It contains the following features for any OTP process:

 当发生问题的进程是OTP进程时(大部分产品级的系统都是OTP 进程),你就可以立即得到更多的工具来检查它们。
 一般你可以在sys23模块找到你想要的。查阅它的文档，你会发现为什么它这么有用啦。它包括了针对OTP进程的以下特性：

 • logging of all messages and state transitions, both to the shell or to a file, or even in an internal buffer to be queried;
 • statistics (reductions, message counts, time, and so on);
 • fetching the status of a process (metadata including the state);
 • fetching the state of a process (as in the #state{} record);
 • replacing that state
 • custom debugging functions to be used as callbacks
 It also provides functionality to suspend or resume process execution.
 I won’t go into a lot of details about these functions, but be aware that they exist.

 •记录了所有消息和状态转换，可以输出来shell上或指定文件中，甚至可以输出到一个内部 缓冲区(internal buffer)供查询。
 •统计(reductions,消息数，时间等);
 •得到进程的状态(包括数据状态);
 •得到进程的状态(在#state{}中的数据);
 •替换进程的状态;
 •自定义的函数作为回调函数;
 它还提供函数可以把进程挂起或使进程恢复至运行状态。
 我不会在这里去讨论具体的函数，只是提醒下他们确实存在。

[23] http://www.erlang.org/doc/man/sys.html

[23] http://www.erlang.org/doc/man/sys.html