Django是如何处理并发了全局变量的并发请求？ [英] How django handles simultaneous requests with concurrency over global variables?

问题描述

我通过Apache / mod_wsgi的托管Django的实例。我使用 pre_save 和 post_save 信号前值存储，并保存为以后的比较之后。对于我使用全局变量来存储可以在 post_save 信号处理程序要访问的 pre_save 值。

I have a django instance hosted via apache/mod_wsgi. I use pre_save and post_save signals to store the values before and after save for later comparisons. For that I use global variables to store the pre_save values which can be accessed in the post_save signal handler.

我的问题是，如果两个请求A和B同时走到一起请求相同的Web服务，会是并发？而B不应该读这是由反之亦然写的全局变量。

My question is, if two requests A and B come together simultaneously requesting a same web service, will it be concurrent? The B should not read the global variable which is written by A and vice versa.

PS：我不使用任何线程锁定的变量

PS: I don't use any threading Lock on variables.

推荐答案

这部分取决于你的的mod_wsgi 配置。如果您配置为使用每个进程只有一个线程，那么全局变量是安全的 - 尽管我不推荐使用它们，因为各种各样的原因。在多线程配置，没有什么低保请求将不会弄混，如果你使用全局变量。

This partly depends on your mod_wsgi configuration. If you configure it to use only one thread per process, then global variables are safe--although I wouldn't recommend using them, for a variety of reasons. In a multi-thread configuration, there is nothing guaranteeing that requests won't get mixed up if you use global variables.

您应该能够找到一些地方的地方藏匿您需要 pre_save 和 post_save 。我建议你​​把一些更多的思考到您的设计。

You should be able to find some more local place to stash the data you need between pre_save and post_save. I'd recommend putting some more thought into your design.

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