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From Stephan Ewen <se...@apache.org>
Subject Re: Performance Issue
Date Thu, 24 Sep 2015 15:05:52 GMT
Makes sense. The generation process seems to be inherently faster than the
consumption process (Flink program).

Without backpressure, these two will run out of sync, and Kafka does not do
any backpressure (by design).

On Thu, Sep 24, 2015 at 4:51 PM, Rico Bergmann <info@ricobergmann.de> wrote:

> The test data is generated in a flink program running in a separate jvm.
> The generated data is then written to a Kafka topic from which my programs
> reads the data ...
>
>
>
> Am 24.09.2015 um 14:53 schrieb Aljoscha Krettek <aljoscha@apache.org>:
>
> Hi Rico,
> are you generating the data directly in your flink program or some
> external queue, such as Kafka?
>
> Cheers,
> Aljoscha
>
> On Thu, 24 Sep 2015 at 13:47 Rico Bergmann <info@ricobergmann.de> wrote:
>
>> And as side note:
>>
>> The problem with duplicates seems also to be solved!
>>
>> Cheers Rico.
>>
>>
>>
>> Am 24.09.2015 um 12:21 schrieb Rico Bergmann <info@ricobergmann.de>:
>>
>> I took a first glance.
>>
>> I ran 2 test setups. One with a limited test data generator, the outputs
>> around 200 events per second. In this setting the new implementation keeps
>> up with the incoming message rate.
>>
>> The other setup had an unlimited generation (at highest possible rate).
>> There the same problem as before can be observed. After 2 minutes runtime
>> the output of my program is more than a minute behind ... And increasing
>> over time. But I don't know whether this could be a setup problem. I
>> noticed the os load of my testsystem was around 90%. So it might be more a
>> setup problem ...
>>
>> Thanks for your support so far.
>>
>> Cheers. Rico.
>>
>>
>>
>>
>>
>> Am 24.09.2015 um 09:33 schrieb Aljoscha Krettek <aljoscha@apache.org>:
>>
>> Hi Rico,
>> you should be able to get it with these steps:
>>
>> git clone https://github.com/StephanEwen/incubator-flink.git flink
>> cd flink
>> git checkout -t origin/windows
>>
>> This will get you on Stephan's windowing branch. Then you can do a
>>
>> mvn clean install -DskipTests
>>
>> to build it.
>>
>> I will merge his stuff later today, then you should also be able to use
>> it by running the 0.10-SNAPSHOT version.
>>
>> Cheers,
>> Aljoscha
>>
>>
>> On Thu, 24 Sep 2015 at 09:11 Rico Bergmann <info@ricobergmann.de> wrote:
>>
>>> Hi!
>>>
>>> Sounds great. How can I get the source code before it's merged to the
>>> master branch? Unfortunately I only have 2 days left for trying this out ...
>>>
>>> Greets. Rico.
>>>
>>>
>>>
>>> Am 24.09.2015 um 00:57 schrieb Stephan Ewen <sewen@apache.org>:
>>>
>>> Hi Rico!
>>>
>>> We have finished the first part of the Window API reworks. You can find
>>> the code here: https://github.com/apache/flink/pull/1175
>>>
>>> It should fix the issues and offer vastly improved performance (up to
>>> 50x faster). For now, it supports time windows, but we will support the
>>> other cases in the next days.
>>>
>>> I'll ping you once it is merged, I'd be curious if it fixes your issue.
>>> Sorry that you ran into this problem...
>>>
>>> Greetings,
>>> Stephan
>>>
>>>
>>> On Mon, Sep 7, 2015 at 12:00 PM, Rico Bergmann <info@ricobergmann.de>
>>> wrote:
>>>
>>>> Hi!
>>>>
>>>> While working with grouping and windowing I encountered a strange
>>>> behavior. I'm doing:
>>>>
>>>> dataStream.groupBy(KeySelector).window(Time.of(x,
>>>> TimeUnit.SECONDS)).mapWindow(toString).flatten()
>>>>
>>>>
>>>> When I run the program containing this snippet it initially outputs
>>>> data at a rate around 150 events per sec. (That is roughly the input rate
>>>> for the program). After about 10-30 minutes the rate drops down below 5
>>>> events per sec. This leads to event delivery offsets getting bigger and
>>>> bigger ...
>>>>
>>>> Any explanation for this? I know you are reworking the streaming API.
>>>> But it would be useful to know, why this happens ...
>>>>
>>>> Cheers. Rico.
>>>>
>>>
>>>

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