Hi Wes,

We have our own implementation of something like Flight for flexibility of use. 

The main thing that I am trying to figure out is how to get the dictionary record batches properly deserialized on the server side. On the client side, I can deserialize them properly using the dictionarymemo directly from the record batch we create, but on the other side I do not have access to the same dictionarymemo. How is this passed in Flight? I have been trying to find this in the source code but haven't yet.

Thanks,
Dawson

On Fri, Feb 12, 2021 at 3:34 PM Wes McKinney <wesmckinn@gmail.com> wrote:
hi Dawson — you need to follow the IPC stream protocol, e.g. what
RecordBatchStreamWriter or RecordBatchStreamReader are doing
internally. Is there a reason you cannot use these interfaces
(particularly their internal bits, which are also used to implement
Flight where messages are split across different elements of a gRPC
stream)?

I'm not sure that I would advise you to deal with dictionary
disassembly and reconstruction on your own unless it's your only
option. That said if you look in the unit test suite you should be
able to find examples of where DictionaryBatch IPC messages are
reconstructed manually, and then used to reconstitute a RecordBatch
IPC message using the arrow::ipc::ReadRecordBatch API. We can try to
help you look in the right place, let us know.

Thanks,
Wes

On Fri, Feb 12, 2021 at 2:58 PM Dawson D'Almeida
<dawson.dalmeida@snowflake.com> wrote:
>
> I am trying to create a record batch containing any number of dictionary and/or normal arrow arrays, serialize the record batch into bytes (a normal std::string), and send it via grpc to another server process. On that end we receive the arrow bytes and deserialize using the bytes and the schema.
>
> Is there a standard way to serialize/deserialize these dictionary arrays? It seems like all of the info is packaged correctly into the record batch.
>
> I've looked through a lot of the c++ apache arrow source and test code but I can't find how to approach our use case.
>
> The current failure is:
> Field with memory address 140283497044320 not found
> from the returns status from arrow::ipc::ReadRecordBatch
>
> Thanks,
> --
> Dawson d'Almeida
> Software Engineer
>
> MOBILE  +1 360 499 1852
> EMAIL  dawson.dalmeida@snowflake.com
>
>
> Snowflake Inc.
> 227 Bellevue Way NE
> Bellevue, WA, 98004


--
Dawson d'Almeida
Software Engineer

MOBILE  +1 360 499 1852
EMAIL  dawson.dalmeida@snowflake.com


Snowflake Inc.
227 Bellevue Way NE
Bellevue, WA, 98004