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
> > >
> >
