Thanks Wes!
I'm working on the integrating and testing the necessary changes in our dev
environment. I'll submit a PR once things are working.
Best,
Brian
On 3/16/19, 4:24 PM, "Wes McKinney" <wesmck...@gmail.com> wrote:
EXTERNAL
hi Brian,
Please feel free to submit a PR to add the requisite APIs that you
need for your application. Antoine or I or others should be able to
give prompt feedback since we know this code pretty well.
Thanks
Wes
On Sat, Mar 16, 2019 at 11:40 AM Brian Bowman <brian.bow...@sas.com> wrote:
>
> Hi Wes,
>
> Thanks for the quick reply! To be clear, the usage I'm working on needs
to own both the Open FileDescriptor and corresponding mapped memory. In other
words ...
>
> SAS component does both open() and mmap() which could be for READ or
WRITE.
>
> -> Calls low-level Parquet APIs to read an existing file or write a new
one. The open() and mmap() flags are guaranteed to be correct.
>
> At some later point SAS component does an unmap() and close().
>
> -Brian
>
>
> On 3/14/19, 3:42 PM, "Wes McKinney" <wesmck...@gmail.com> wrote:
>
> hi Brian,
>
> This is mostly an Arrow platform question so I'm copying the Arrow
mailing list.
>
> You can open a file using an existing file descriptor using
ReadableFile::Open
>
>
https://github.com/apache/arrow/blob/master/cpp/src/arrow/io/file.h#L145
>
> The documentation for this function says:
>
> "The file descriptor becomes owned by the ReadableFile, and will be
> closed on Close() or destruction."
>
> If you want to do the equivalent thing, but using memory mapping, I
> think you'll need to add a corresponding API to MemoryMappedFile. This
> is more perilous because of the API requirements of mmap -- you need
> to pass the right flags and they may need to be the same flags that
> were passed when opening the file descriptor, see
>
>
https://github.com/apache/arrow/blob/master/cpp/src/arrow/io/file.cc#L378
>
> and
>
>
https://github.com/apache/arrow/blob/master/cpp/src/arrow/io/file.cc#L476
>
> - Wes
>
> On Thu, Mar 14, 2019 at 1:47 PM Brian Bowman <brian.bow...@sas.com>
wrote:
> >
> > The ReadableFile class (arrow/io/file.cc) has utility methods
where a FileDescriptor is either passed in or returned, but I don’t see how
this surfaces through the API.
> >
> > Is there a way for application code to control the open lifetime of
mmap()’d Parquet files by passing an already open FileDescriptor to Parquet
low-level API open/close methods?
> >
> > Thanks,
> >
> > Brian
> >
>
>
>
