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From Guozhang Wang <wangg...@gmail.com>
Subject Re: Kafka Streams Session store performance degradation from 0.10.2.1 to 0.11.0.3
Date Sat, 17 Nov 2018 00:26:56 GMT
Hi Jonathan,

Could you create a JIRA with all the current available information uploaded
on the ticket for me to further investigate the issue? This way we will not
lose track of it (email list is not the best venue for potential bug
investigation :).

At the mean time, I will try to compare the source code of 0.10.2 and 2.0
and see if I can eyeball any obvious issues.

Guozhang

On Thu, Nov 8, 2018 at 1:39 PM Matthias J. Sax <matthias@confluent.io>
wrote:

> Thanks for verifying.
>
> >> From our perspective, it appears something happened after 0.10.2.1 that
> made the LRU Cache much slower for our use case.
>
> That is what I try to figure out. I went over the 0.10.2.2 to 0.11.0.3
> Jiras but found nothing I could point out. There are couple of
> SessionStore related tickets, but none of them should have an effect
> like this.
>
> To narrow it down, it would be helpful to test with other versions, too.
> Maybe 0.10.2.2 and 0.11.0.0 to see when the issue was introduced.
>
> Can you also profile v0.10.2.1 so we can compare?
>
> > What would you recommend for our next steps?
>
> Not sure. If you could help us to track down the issue, that would be
> most helpful so get a fix (and you could run from a SNAPSHOT version to
> get the fix -- not sure if this would be an option for you).
>
>
> -Matthias
>
>
>
> On 11/7/18 3:47 PM, jonathangordon@newrelic.com wrote:
> > Hi Matthias,
> >
> > I upgraded to 2.0.0 and we're experiencing the same problem. I've posted
> a new screengrab of a thread profile:
> >
> > https://imgur.com/a/2wncPHw
> >
> > From our perspective, it appears something happened after 0.10.2.1 that
> made the LRU Cache much slower for our use case. What would you recommend
> for our next steps?
> >
> > Jonathan
> >
> > On 2018/11/06 19:22:16, "Matthias J. Sax" <matthias@confluent.io>
> wrote:
> >> Not sure atm why you see a performance degradation. Would need to dig
> >> into the details.
> >>
> >> However, did you consider to upgrade to 2.0 instead or 0.11?
> >>
> >> Also note that we added a new operator `suppress()` in upcoming 2.1
> >> release, that allows you to do rate control without caching:
> >>
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-328%3A+Ability+to+suppress+updates+for+KTables
> >>
> >> Hope this helps.
> >>
> >>
> >> -Matthias
> >>
> >> On 11/6/18 9:49 AM, Jonathan Gordon wrote:
> >>> I have a Kafka Streams app that I'm trying to upgrade from 0.10.2.1 to
> >>> 0.11.0.3 but when I do I notice that CPU goes way up and consumption
> goes
> >>> down. A thread profile indicates that the most expensive task is
> during our
> >>> aggregation, fetching from the cache.
> >>>
> >>> Thread profile with caching:
> >>> https://imgur.com/l5VEsC2
> >>>
> >>> If I disable the cache both performance and consumption are good but
> we are
> >>> producing every single aggregation modification, which is not what we
> want.
> >>>
> >>> Thread profile without caching:
> >>> https://imgur.com/a/JK3nkou
> >>>
> >>> I read this thread, which seems relevant e
> >>>
> >>>
> https://lists.apache.org/thread.html/2b44e74eaec7172b107bcff96861cf8b4837f55a44714f69d033cc2e@%3Cusers.kafka.apache.org%3E
> >>>
> >>> Notably: "Note, that caching was _not_ introduced to reduce the writes
> to
> >>> RocksDB, but to reduce the write the the changelog topic and to reduce
> the
> >>> number of records send downstream."
> >>>
> >>> So how can we reduce the number of records sent downstream while
> >>> maintaining the same performance characteristics that we have with
> caching
> >>> turned off? Or put another way, how can I upgrade my app without
> taking a
> >>> hit in performance or behavior?
> >>>
> >>> Thanks!
> >>>
> >>
> >>
>
>

-- 
-- Guozhang

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