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From Guozhang Wang <wangg...@gmail.com>
Subject Re: Streams SessionStore - bug or documentation error?
Date Sat, 12 Jan 2019 00:45:51 GMT
Hello Tom,

This is a long-delayed reply, but I've finally discovered the bug you
reported inside session stores, and here is a fix that I've put up for
trunk:

https://github.com/apache/kafka/pull/6134

Sorry it took a while for me to get back to you!


Guozhang

On Wed, Oct 17, 2018 at 8:31 AM Guozhang Wang <wangguoz@gmail.com> wrote:

> Tom,
>
> I think there is a documentation error on the `findSessions` function,
> where the last parameter should really be "the start timestamp of the
> latest session to search for".
>
> So back to your example, if you want to find "any sessions that has an
> overlap of [T2, T4)" you should be calling `findSessions(K1, T4, T2)`
> instead, i.e. the second parameter should be larger than the third,
> otherwise there is no "range" to search for.
>
> I will go ahead and update the java doc accordingly.
>
> Guozhang
>
>
> On Tue, Oct 16, 2018 at 8:13 AM Guozhang Wang <wangguoz@gmail.com> wrote:
>
>> Hello Tom,
>>
>> Thanks for reporting the observed issue. I've looked into the source code
>> and I agree with you that there is indeed a mistake interpreting the
>> parameters.
>>
>> I'll file a JIRA to keep track, and fix it asap.
>>
>>
>> Guozhang
>>
>> On Fri, Oct 12, 2018 at 10:06 AM Thomas Becker <Thomas.Becker@tivo.com>
>> wrote:
>>
>>> I've been experimenting with the streams SessionStore and found some
>>> behavior that contradicts the javadoc. Specifically: I have a SessionStore,
>>> and put() a session with key K1 and session of time T0-T5. I then call
>>> findSessions("K1", T2, T4) and it comes back empty. I would expect the
>>> session to be returned since, according to the documentation that call
>>> fetches "any sessions with the matching key and the sessions end is >=
>>> earliestSessionEndTime and the sessions start is <= latestSessionStartTime"
>>> and obviously T5 >= T2 and T0 <= T4. From the behavior I see, the third
>>> parameter to this method should be called "latestSession*End*Time". That
>>> is, the method returns all sessions that end within the range given. Any
>>> thoughts?
>>>
>>>
>>>
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>>
>>
>> --
>> -- Guozhang
>>
>
>
> --
> -- Guozhang
>


-- 
-- Guozhang

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