Re: [PATCH] Work around performance bug in subprocess.Popen.communicate()

From: Catalin Marinas <catalin.marinas@gmail.com>
Date: Jul 31, 2009, 11:27 UTC
Message-ID: <b0943d9e0907310427r7e59aa5fi5e5ff5e3f3c03819@mail.gmail.com>
In-Reply-To: <20090731093632.7018.24435.stgit@october.e.vtech>

2009/7/31 Karl Wiberg <kha@virtutech.com>:

Show 11 quoted lines

> @@ -110,7 +110,9 @@ class Run:
>                                  stdin = subprocess.PIPE,
>                                  stdout = subprocess.PIPE,
>                                  stderr = subprocess.PIPE)
> -            outdata, errdata = p.communicate(self.__indata)
> +            if self.__indata:
> +                p.stdin.write(self.__indata)
> +            outdata, errdata = p.communicate()
>             self.exitcode = p.returncode
>         except OSError, e:
>             raise self.exc('%s failed: %s' % (self.__cmd[0], e))

But can this not lead to a deadlock if the __indata is big? The stdout of the created process is only processed once the whole __indata is written. I thought communicate() was created to avoid this issue.

-- 
Catalin