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From Anoop Johnson <anoop.k.john...@gmail.com>
Subject Re: Java Parquet to Arrow Conversion
Date Tue, 25 Aug 2020 17:29:57 GMT
Thanks Micah. Is there a Jira or pull request I could follow for the C++
implementation for arbitrary nesting? How about maps?

On Tue, Aug 25, 2020 at 9:10 AM Micah Kornfield <emkornfield@gmail.com>
wrote:

> Also does the C++ Parquet to Arrow reader have any such limitations?
>
>
> The C++ implementation can currently either read nested structs or nested
> lists but not a combination of the two.  It is actively being worked on to
> be able to handle arbitrary nesting.
>
> On Tue, Aug 25, 2020 at 1:15 AM Anoop Johnson <anoop.k.johnson@gmail.com>
> wrote:
>
>> If I read the Iceberg vectorized reader code right, it does not support
>> nested types (same limitation as Spark's built-in vectorized parquet
>> reader). Is that correct? Also does the C++ Parquet to Arrow reader have
>> any such limitations?
>>
>> On Wed, Aug 19, 2020 at 9:37 AM Jacques Nadeau <jacques@apache.org>
>> wrote:
>>
>>> I believe there is code in the iceberg project to do this in pure Java
>>> [1]. Right now, there isn't a pure java implementation in the Arrow project.
>>>
>>> [1]
>>> https://github.com/apache/iceberg/tree/master/arrow/src/main/java/org/apache/iceberg/arrow/vectorized
>>>
>>> On Wed, Aug 19, 2020 at 5:18 AM Chris Nuernberger <chris@techascent.com>
>>> wrote:
>>>
>>>> Also, javacpp has prepackaged C++ bindings to arrow for multiple OS's:
>>>>
>>>> http://bytedeco.org/javacpp-presets/arrow/apidocs/
>>>>
>>>> We have had success with javacpp
>>>> <https://github.com/techascent/tech.opencv> in the past and it is much
>>>> better now that their preprocess is based on Clang.
>>>>
>>>> On Tue, Aug 18, 2020 at 4:16 PM Chris Nuernberger <chris@techascent.com>
>>>> wrote:
>>>>
>>>>> Thanks, that is helpful.
>>>>>
>>>>> Chris
>>>>>
>>>>> On Tue, Aug 18, 2020 at 10:24 AM Micah Kornfield <
>>>>> emkornfield@gmail.com> wrote:
>>>>>
>>>>>> Hi Chris,
>>>>>> There is an open PR to support this through C++'s Dataset
>>>>>> functionality [1]. There was also a prior attempt that went stale
and I
>>>>>> can't find at the moment.
>>>>>>
>>>>>> IIUC the main missing component at this point before the PR gets
>>>>>> merged is integration to honor "-XX:MaxDirectMemorySize" settings.
>>>>>>
>>>>>> -Micah
>>>>>>
>>>>>> [1] https://github.com/apache/arrow/pull/7030
>>>>>>
>>>>>>
>>>>>>
>>>>>> [1] https://github.com/apache/arrow/pull/7030
>>>>>>
>>>>>> On Tue, Aug 18, 2020 at 6:48 AM Chris Nuernberger <
>>>>>> chris@techascent.com> wrote:
>>>>>>
>>>>>>> Hey,
>>>>>>>
>>>>>>> We were wondering what the best way to convert a parquet file
to an
>>>>>>> arrow file would be via a java pathway.  I notice that the c++
layer
>>>>>>> appears to have this conversion.
>>>>>>>
>>>>>>> The best hint I have see so far is this gist:
>>>>>>>
>>>>>>> https://gist.github.com/animeshtrivedi/76de64f9dab1453958e1d4f8eca1605f
>>>>>>>
>>>>>>> I also found this jni pathway for ORC files:
>>>>>>> https://github.com/apache/arrow/tree/master/cpp/src/jni
>>>>>>>
>>>>>>> Another thought I had was to use the JNA or JNR and bind to the
C
>>>>>>> glib pathway.
>>>>>>>
>>>>>>> Thanks for any help,
>>>>>>>
>>>>>>> Chris
>>>>>>>
>>>>>>

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