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From Anoop Johnson <anoop.k.john...@gmail.com>
Subject Re: Java Parquet to Arrow Conversion
Date Tue, 25 Aug 2020 08:14:58 GMT
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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