I guess I would be of some help w.r.t Big Endian systems, I in fact want to be
part of this development and testing work, quite held-up now for a month.
Thanks,Sanjay
> From: wesmck...@gmail.com
> Date: Sat, 6 Aug 2016 17:52:26 -0700
> Subject: Re: Is there plan to support BigEndian Systems like SUN SPARC
> Hardware ?
> To: dev@arrow.apache.org
> CC: emkornfi...@gmail.com; jul...@dremio.com
>
> I suspect that relaxing the constraint to native endianness (and
> including this in any IPC/RPC metadata (per ARROW-245) will not cause
> too many problems. One of the challenges for us will be testing and
> continuous integration -- what are the options for running the test
> suite on a regular basis on big endian platforms? I know that in
> pandas we occasionally ran into esoteric test failures for the PPC /
> big-endian Debian package builds but for the most part there haven't
> been any problems.
>
> - Wes
>
> On Fri, Aug 5, 2016 at 4:39 AM, Sanjay Rao <getsanjay...@live.com> wrote:
> > Some places where explicit check for Little Endian is there-
> > ./memory/src/main/java/io/netty/buffer/UnsafeDirectLittleEndian.java: if
> > (!NATIVE_ORDER || buf.order() != ByteOrder.BIG_ENDIAN)
> > {./memory/src/main/java/io/netty/buffer/UnsafeDirectLittleEndian.java:
> > throw new IllegalStateException("Arrow only runs on LittleEndian systems.");
> > Sanjay
> >> From: pchan...@maprtech.com
> >> Date: Thu, 4 Aug 2016 17:04:34 -0700
> >> Subject: Re: Is there plan to support BigEndian Systems like SUN SPARC
> >> Hardware ?
> >> To: dev@arrow.apache.org; emkornfi...@gmail.com
> >> CC: jul...@dremio.com
> >>
> >> Drill's assumption of little endian is in the ValueVector code, and Arrow
> >> has inherited the same assertion. (
> >> https://github.com/apache/arrow/blob/master/java/memory/src/main/java/io/netty/buffer/UnsafeDirectLittleEndian.java#L58
> >> )
> >>
> >> In the Java implementation, the underlying Netty implementation handles the
> >> conversion between endianness fairly well, so potentially this assert can
> >> be removed from here and Drill can move this higher up in the Drill code.
> >>
> >>
> >> Parth
> >>
> >> On Thu, Aug 4, 2016 at 1:14 PM, Micah Kornfield <emkornfi...@gmail.com>
> >> wrote:
> >>
> >> > Hi Julien,
> >> > Thats the theory. I don't think that there is anything in the C++ code
> >> > base that should break but we don't have access to hardware to verify
> >> > that.
> >> >
> >> > The java Arrow code currently asserts that it is running on a little
> >> > endian
> >> > machine. I did a very quick scan of the Java code and didn't see
> >> > anything
> >> > there would break on a big-endian system, but according to at least one
> >> > person who is working on Drill, it seems that Drill assumes little
> >> > endianness (I don't know if this is in Arrow/ValueVector code or it is
> >> > higher up the stack in the Drill code).
> >> >
> >> > Thanks,
> >> > Micah
> >> >
> >> >
> >> > On Thu, Aug 4, 2016 at 11:36 AM, Julien Le Dem <jul...@dremio.com> wrote:
> >> >
> >> > > So it sounds like right now it just works as long as there are no
> >> > > inter-system communication (with different endianness) because both
> >> > > java
> >> > > and c++ code just use the underlying endianness.
> >> > > Is that correct?
> >> > >
> >> > >
> >> > > On Thu, Aug 4, 2016 at 11:17 AM, Micah Kornfield
> >> > > <emkornfi...@gmail.com>
> >> > > wrote:
> >> > >
> >> > >> Hi Sanjay,
> >> > >> I think we are trying to work that out now. As you've seen with some
> >> > >> of
> >> > >> you initial investigation we have no coverage for big-endian machines
> >> > yet.
> >> > >> But in the long run, we should be able to make it work (it seems like
> >> > >> there
> >> > >> might be some difference of opinion on how to make it work).
> >> > >>
> >> > >> Thanks,
> >> > >> Micah
> >> > >>
> >> > >> On Mon, Aug 1, 2016 at 11:16 AM, Sanjay Rao <getsanjay...@live.com>
> >> > >> wrote:
> >> > >>
> >> > >> > Hi Wes, Hi Micah,
> >> > >> > I understood what you meant, so point 2. Arrow working with Big
> >> > >> > Endian
> >> > >> > machine to Big Endian shouldn't be an issue right ?
> >> > >> > Please confirm.
> >> > >> > Thanks,Sanjay
> >> > >> > > From: wesmck...@gmail.com
> >> > >> > > Date: Mon, 1 Aug 2016 11:07:07 -0700
> >> > >> > > Subject: Re: Is there plan to support BigEndian Systems like SUN
> >> > SPARC
> >> > >> > Hardware ?
> >> > >> > > To: dev@arrow.apache.org; emkornfi...@gmail.com
> >> > >> > >
> >> > >> > > hey Micah,
> >> > >> > >
> >> > >> > > On Mon, Aug 1, 2016 at 11:02 AM, Micah Kornfield <
> >> > >> emkornfi...@gmail.com>
> >> > >> > wrote:
> >> > >> > > > Hi Wes,
> >> > >> > > > The point I was trying to argue from an earlier thread is that
> >> > >> > > > the
> >> > >> most
> >> > >> > > > common cases for relocation are:
> >> > >> > > > 1. Little endian machine to little endian machine (most likely
> >> > same
> >> > >> > > > machine)
> >> > >> > > > 2. big endian machine to big endian machine (most likely same
> >> > >> machine)
> >> > >> > > > 3. big endian machine to little endian machine or vice versa
> >> > >> > > >
> >> > >> > > > The purpose of the metadata would be to make use-cases 1 and 2
> >> > >> possible
> >> > >> > > > without byte-swapping. Use case 3 would obviously require byte
> >> > >> > swapping
> >> > >> > > > but for an initial implementation the code could simply indicate
> >> > >> that
> >> > >> > it is
> >> > >> > > > not supported.
> >> > >> > > >
> >> > >> > > > This seems less complex to me than actually implementing any
> >> > >> > > > sort
> >> > of
> >> > >> > > > byte-swapping logic while still supporting the widest variety of
> >> > >> > hardware
> >> > >> > > > with the same code for the most common use-cases.
> >> > >> > >
> >> > >> > > This makes sense. My comments were for the situation that a big
> >> > endian
> >> > >> > > system would be exposing memory to an unknown consumer -- for
> >> > example,
> >> > >> > > if we implemented an RPC wire format for Arrow memory, then in
> >> > general
> >> > >> > > a big endian system would need to send little-endian integers to
> >> > >> > > an
> >> > >> > > arbitrary receiver. I'm not sure the best way to provide for easy
> >> > >> > > native-endianness support for cases 1/2, but trying to fully solve
> >> > >> > > this problem now seems premature until we've established some of
> >> > these
> >> > >> > > tools (so long as we haven't painted ourselves into a corner).
> >> > >> > >
> >> > >> > > - Wes
> >> > >> > >
> >> > >> > > >
> >> > >> > > > Thanks,
> >> > >> > > > Micah
> >> > >> > > >
> >> > >> > > > P.S. If anybody can provide pointers I'd be interested to
> >> > understand
> >> > >> > which
> >> > >> > > > pieces of the java code make assumptions about
> >> > >> > > > little-endianness.
> >> > >> >
> >> > >> >
> >> > >>
> >> > >
> >> > >
> >> > >
> >> > > --
> >> > > Julien
> >> > >
> >> >
> >
