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From Miki Tebeka <m...@353solutions.com>
Subject Re: [C++] Storing/retreiving a Table in plasma
Date Mon, 20 May 2019 14:48:09 GMT
OK, almost working. I get "Write out of bounds" when running the code at
https://github.com/353solutions/carrow/blob/plasma/plasma.cc

Any ideas?

Full output:
batch size = 224
buf size = 224
error: write: Write out of bounds

On Mon, May 20, 2019 at 5:21 PM Miki Tebeka <miki@353solutions.com> wrote:

> Thanks Wes
>
> On Mon, May 20, 2019 at 4:24 PM Wes McKinney <wesmckinn@gmail.com> wrote:
>
>> See https://issues.apache.org/jira/browse/ARROW-5377
>>
>> On Mon, May 20, 2019 at 8:15 AM Wes McKinney <wesmckinn@gmail.com> wrote:
>> >
>> > hi Miki,
>> >
>> > Steps
>> >
>> > * Convert the Table to a sequence of RecordBatch objects. You can use
>> > arrow::TableBatchReader to do this [1]
>> > * Write a stream using MockOutputStream [2]
>> > * Use the reported size of the total stream to allocate memory in Plasma
>> > * Write a real stream using arrow::io::FixedSizeBufferWriter
>> >
>> > I'm interested at some point to reduce the amount of boilerplate
>> > associated with this process, and also to avoid multiple metadata
>> > serialization and record batch disassembly steps. I'll open a JIRA
>> > issue
>> >
>> > We'd be delighted if you would contribute to the C++ documentation at
>> > https://github.com/apache/arrow/tree/master/docs/source/cpp
>> >
>> > - Wes
>> >
>> > [1]:
>> https://github.com/apache/arrow/blob/master/cpp/src/arrow/table.h#L340
>> > [2]:
>> https://github.com/apache/arrow/blob/7a5562174cffb21b16f990f64d114c1a94a30556/cpp/src/arrow/io/memory.h#L89
>> >
>> > On Mon, May 20, 2019 at 7:24 AM Miki Tebeka <miki@353solutions.com>
>> wrote:
>> > >
>> > > Hi,
>> > >
>> > > I'm looking for an example on how to store/retrieve a an arrow::Table
>> in plasma. The examples I see in the documentation site are for basic types.
>> > >
>> > > My end goal is to create data (Table) in C++, store it in plasma and
>> read if from Python.
>> > >
>> > > From reading around, I need to allocate buffer in plasma, but how can
>> I find the size of the Table to allocate the table? And how can I serialize
>> it into the created Buffer?
>> > >
>> > > Thanks,
>> > > Miki
>>
>

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