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From Micah Kornfield <emkornfi...@gmail.com>
Subject Re: Java Parquet to Arrow Conversion
Date Tue, 25 Aug 2020 16:10:04 GMT
>
> 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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