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From Aljoscha Krettek <aljos...@apache.org>
Subject Re: Interpretation of Trigger and Eviction on a window
Date Mon, 30 Nov 2015 09:53:20 GMT
Hi,
the function is in fact applied to the remaining elements (at least I hope it is). So the
first sentence should be the correct one.

Cheers,
Aljoscha
> On 28 Nov 2015, at 03:14, Nirmalya Sengupta <sengupta.nirmalya@gmail.com> wrote:
> 
> Hello Fabian,
> 
> From your reply to this thread: 
> ' it is correct that the evictor is called BEFORE the window function is applied because
this is required to support certain types of sliding windows. '
> 
> This is clear to me now. However, my point was about the way it is described in the User-guide.
The guide says this:
> ' After the trigger fires, and before the function (e.g., sum, count) is applied to the
window contents, an optional Evictor removes some elements from the beginning of the window
before the remaining elements are passed on to the function '
> 
> As I read it again, I see where the problem lies. It says some elements are removed before
the **rest** are passed to the function. This is not what happens, I think. Evictor removes
elements and the function sees this set of removed elements, not the remaining elements. Remaining
elements remain in the window and are perhaps picked up by the Evictor next time.
> 
> Carrying on from your elaboration, I think guide's statement can be better rearranged
as:
> 
> ' After the trigger fires, the function (e.g., sum, count) is applied to the entire contents
of the window. However, an optionally provided Evictor, removes some elements from the beginning
of the window, according to the criteria of eviction. The function is then applied to this
set of __removed__ elements. '
>  
> Let me know if I am way off the mark here.
> 
> -- Nirmalya
> 
> -- 
> Software Technologist
> http://www.linkedin.com/in/nirmalyasengupta
> "If you have built castles in the air, your work need not be lost. That is where they
should be.
> Now put the foundation under them."


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