Re: Long paths for tablespace leads to uninterruptible hang in Windows

On Tue, Oct 15, 2013 at 4:14 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> On Tue, Oct 15, 2013 at 6:28 PM, Magnus Hagander <magnus(at)hagander(dot)net> wrote:
>> On Tue, Oct 15, 2013 at 2:55 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>>> On Mon, Oct 14, 2013 at 1:30 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>>>>> Well, that sucks. So it's a Windows bug.
>>>>
>>>> It's not clear to me that we should do anything about this at all,
>>>> except perhaps document that people should avoid long tablespace
>>>> path names on an unknown set of Windows versions. We should not
>>>> be in the business of working around any and every bug coming out
>>>> of Redmond.
>>>
>>> It's sort of incomprehensible to me that Microsoft has a bug like this
>>> and apparently hasn't fixed it. But I think I still favor trying to
>>> work around it. When people try to use a long data directory name and
>>> it freezes the system, some of them will blame us rather than
>>> Microsoft. We've certainly gone to considerable lengths to work
>>> around extremely strange bugs in various compiler toolchains, even
>>> relatively obscure ones. I don't particularly see why we shouldn't do
>>> the same here.
>>
>> I agree we'll probably want to work around it in the end, but I still
>> think it should be put to Microsoft PSS if we can. The usual - have we
>> actually produced a self-contained example that does just this (and
>> doesn't include the full postgres support) and submitted it to
>> *microsoft* for comments?
>
> I have written a self contained win32 console application with which
> the issue can be reproduced.
> The application project is attached with this mail.
>
> Here is brief description of the project:
> This project is created using MSVC 2010, but even if somebody
> doesn't have this version of VC, functions in file long_path.cpp can
> be copied and
> used in new project.
> In project settings, I have changed Character Set to "Use Multi-Byte
> Character Set" which is what Postgres uses.
>
> It takes 3 parameters as input:
> existingpath - path for which link will be created. this path should
> be an already
> existing path with one level less than actual
> path. For example,
> if we want to create a link for path
> "E:/PG_Patch/Long_Path/path_dir/version_dir",
> then this should be "E:/PG_Patch/Long_Path/path_dir".
> newpath - path where link needs to be created. it should be
> non-absolute path
> of format "linked_path_dir/test_version"
> curpath - path to set as current working directory path, it
> should be the
> location to prepend to newpath
>
> Currently I have used input parameters as
> E:/PG_Patch/Long_Path/path_dir
> linked_path_dir/test_version
> E:/PG_Patch/Long_Path/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
>
> Long path is much less than 260 char limit on windows, I have
> observed this problem with path length > 130 (approx.)

And this reliably reproduces the hang? On which Windows version(s)?

--
Robert Haas
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