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Date: Sat, 31 Jan 2015 11:04:53 +0100
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Subject: Re: Design Question in Expression API
From: Aljoscha Krettek <aljoscha@apache.org>
To: dev@flink.apache.org
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Yes, that's exactly my reasoning for wanting to hide it.

On Sat, Jan 31, 2015 at 10:32 AM, Stephan Ewen <sewen@apache.org> wrote:
> My first Intuition is to not expose the row data type. If we add columnar
> executing later, there may never be a Row data type during runtime (cp
> paper on hyper runtime engine).
>
> For these declarative operations, I think it is a big advantage to keep the
> underpinnings strictly separate so we can change the execution model.
>
> Also, I think that explicit switches between the logical and physical
> abstraction (switching from class type to logical row type and vice versa)
> make things more transparent to the user. As an example: A filter in a
> logical query expression may be pushed down, a filter defined as as udf on
> a physical type is not pushed down.