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Posted to user@flink.apache.org by Elias Levy <fe...@gmail.com> on 2016/04/09 03:18:44 UTC

WindowedStream sum behavior

I am wondering about the expected behavior of the sum method.  Obviously it
sums a specific field in a tuple or POJO. But what should one expect in
other fields?  Does sum keep the first field, last field or there aren't
any guarantees?

Re: WindowedStream sum behavior

Posted by Aljoscha Krettek <al...@apache.org>.

Hi,
there no guarantees for the fields other than the summed field (and
eventual key fields). I think in practice it's either the fields from the
first or last record but I wouldn't rely on that.

Cheers,
Aljoscha

On Sat, 9 Apr 2016 at 03:19 Elias Levy <fe...@gmail.com> wrote:

> I am wondering about the expected behavior of the sum method.  Obviously
> it sums a specific field in a tuple or POJO. But what should one expect in
> other fields?  Does sum keep the first field, last field or there aren't
> any guarantees?
>