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Date: Thu, 3 Feb 2011 09:54:11 -0500
Message-ID: <AANLkTinUYVDvm1LvB-eUTnBTPEJj6XRDGWawLJ1i7OKi@mail.gmail.com>
Subject: Re: TDB in a unit test -- or -- when is a close not a close?
From: Benson Margulies <bimargulies@gmail.com>
To: jena-users@incubator.apache.org
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Is there a way to enable  fixed.opt?

On Thu, Feb 3, 2011 at 4:22 AM, Andy Seaborne
<andy.seaborne@epimorphics.com> wrote:
> Ah - good old 4724038 [1]. =C2=A0Currently #4 in the Java RFE hit parade =
[2]
> despite the fact most people call it a bug.
>
> Summary: It's a Windows-ism to do with "deleting" memory mapped files. Th=
ey
> are still mapped by the OS.
>
> I've not tried the GC/loop dance. The cleaner workaround does not look li=
ke
> it will work on other JVMs which will concern some users.
>
> There is an in-memory TDB version. =C2=A0Good for testing, not a performa=
nt
> replacement for memory models - the TDB memory dataset uses a
> copy-in/copy-out RAM disk for true disk semantics.
>
> The magic location name is "--mem--" or there are TDBFactory operations t=
hat
> take no location.
>
> =C2=A0 =C2=A0 =C2=A0 =C2=A0Andy
>
> [1] http://bugs.sun.com/view_bug.do?bug_id=3D4724038
> [2] http://bugs.sun.com/top25_rfes.do
>
> On 03/02/11 02:47, Benson Margulies wrote:
>>
>> We can't get a unit test on Windows to delete a temporary TDB.
>>
>> Now, on the one hand, I saw some code that suggests that with the
>> right assembly descriptor I could have a completely in-memory TDB and
>> avoid this.
>>
>> But, on the other hand, I would think that with a System.gc() and a
>> sleep, we could do this, in spite of Java's annoying lazyiness about
>> closing the backing files of memory mapped files.
>>
>> How confident are you that all the channels and streams get closed?
>
> As confident as I can be.
>
> There is a known problem deleting datasets on Windows 64 bit because of t=
he
> memory mapped file issue. =C2=A0FileMode.direct works.
>
>