Hello, Matthias.

> (4) While I agree that we might want to deprecate it, I am not sure if this 
> should be part of this KIP? 
> Seems to be unrelated? 
> Should this have been part of KIP-319? 
> If yes, we might still want to updated this other KIP? WDYT?

OK, I removed this deprecation from this KIP.

Please, tell me, is there anything else that should be improved to make this 
KIP ready to be implemented.

В Пт, 07/09/2018 в 17:06 -0700, Matthias J. Sax пишет:
> (1) Sounds good to me, to just use IllegalArgumentException for both --
> and thanks for pointing out that Duration can be negative and we need to
> check for this. For the KIP, it would be nice to add to all methods than
> (even if we don't do it in the code but only document in JavaDocs).
> 
> (2) I would argue for a new single method interface. Not sure about the
> name though.
> 
> (3) Even if `#fetch(K, K, long, long)` and `#fetchAll(long, long)` is
> _currently_ not used internally, I would still argue they are both dual
> use -- we might all a new DSL operator at any point that uses those
> methods. Thus to be "future prove" I would consider them dual use.
> 
> > Since the ReadOnlyWindowStore is only used by IQ,
> 
> This contradicts your other statement:
> 
> > org.apache.kafka.streams.state.ReadOnlyWindowStore#fetch(K, long) is used
> > in KStreamWindowAggregate.
> 
> Or do you suggest to move `fetch(K, long)` from `ReadOnlyWindowStore` to
> `WindowStore` ? This would not make sense IMHO, as `WindowStore extends
> ReadOnlyWindowStore` and thus, we would loose this method for IQ.
> 
> 
> (4) While I agree that we might want to deprecate it, I am not sure if
> this should be part of this KIP? Seems to be unrelated? Should this have
> been part of KIP-319? If yes, we might still want to updated this other
> KIP? WDYT?
> 
> 
> -Matthias
> 
> 
> On 9/7/18 12:09 PM, John Roesler wrote:
> > Hey all,
> > 
> > (1): Duration can be negative, just like long. We need to enforce any
> > bounds that we currently enforce. We don't need the `throws` declaration
> > for runtime exceptions, but the potential IllegalArgumentException should
> > be documented in the javadoc for these methods. I still feel that surfacing
> > the ArithmeticException directly would not be a great experience, so I
> > still advocate for wrapping it in an IllegalArgumentException that explains
> > our upper bound for Duration is "max-long number of milliseconds"
> > 
> > (2): I agree with your performance intuition. I don't think creating one
> > object per call to punctuate is going to substantially affect the
> > performance.
> > 
> > I think the deeper problem with Punctuator is that it's currently a SAM
> > interface. If we add a new method to it, we break the source code of anyone
> > passing a function. We can add the new method with a default
> > implementation, as Nikolay suggested, but then you get into figuring out
> > which one to default, and no one's happy. Alternatively, we can just make a
> > brand new interface that is still a single method (but an Instant) and add
> > the appropriate overloads and deprecate the old ones.
> > 
> > (3): I disagree. I think only two methods are dual use, and we should
> > separate the internal from external usages. The internal usage should be
> > added to WindowStore.
> > org.apache.kafka.streams.state.ReadOnlyWindowStore#fetch(K, long) is used
> > in KStreamWindowAggregate.
> > org.apache.kafka.streams.state.ReadOnlyWindowStore#fetch(K, long, long) is
> > used in KStreamKStreamJoin.
> > Both of these usages are as WindowStore, so adding these interfaces to
> > WindowStore would be transparent.
> > 
> > org.apache.kafka.streams.state.ReadOnlyWindowStore#fetch(K, K, long, long)
> > is only used for IQ
> > org.apache.kafka.streams.state.ReadOnlyWindowStore#fetchAll(long, long) is
> > only used for IQ
> > 
> > Since the ReadOnlyWindowStore is only used by IQ, we can safely say that
> > *all* of its methods are external use and can be deprecated and replaced.
> > The first two usages I noted are WindowStore usages, not
> > ReadOnlyWindowStores, and WindowStore is only used *internally*, so it's
> > free to offer `long` methods if needed for performance reasons.
> > 
> > Does this make sense? The same reasoning extends to the other stores.
> > 
> > (4) Yes, that was my suggestion. I'm not sure if anyone is actually using
> > this variant, so it seemed like a good time to just deprecate it and see.
> > 
> > Thoughts?
> > -John
> > 
> > 
> > On Fri, Sep 7, 2018 at 10:21 AM Nikolay Izhikov <nizhi...@apache.org> wrote:
> > 
> > > Hello, Matthias.
> > > 
> > > Thanks, for feedback.
> > > 
> > > > (1) Some methods declare `throws IllegalArgumentException`, others>
> > > 
> > > don't.
> > > 
> > > `duration.toMillis()` can throw ArithmeticException.
> > > It can happen if overflow occurs during conversion.
> > > Please, see source of jdk method Duration#toMillis.
> > > Task author suggest to wrap it to IllegalArgumentException.
> > > I think we should add `throws IllegalArgumentException` for all method
> > > with Duration parameter.
> > > (I updated KIP with this throws)
> > > 
> > > What do you think?
> > > 
> > > > (3) ReadOnlyWindowStore: All three methods are dual use and I think we
> > > 
> > > should not deprecate them.
> > > 
> > > This is my typo, already fixed.
> > > I propose to add new methods to `ReadOnlyWindowStore`.
> > > No methods will become deprecated.
> > > 
> > > > (4) Stores: 3 methods are listed as deprecated but only 2 new methods
> > > 
> > > are added.
> > > 
> > > My proposal based on John Roesler mail [1]:
> > > "10. Stores: I think we can just deprecate without replacement the method
> > > that takes `segmentInterval`."
> > > 
> > > Is it wrong?
> > > 
> > > [1] https://www.mail-archive.com/dev@kafka.apache.org/msg91348.html
> > > 
> > > 
> > > В Чт, 06/09/2018 в 21:04 -0700, Matthias J. Sax пишет:
> > > > Thanks for updating the KIP!
> > > > 
> > > > Couple of minor follow ups:
> > > > 
> > > > (1) Some methods declare `throws IllegalArgumentException`, others
> > > > don't. It's runtime exception and thus it's not required to declare it
> > > > -- it just looks inconsistent in the KIP and maybe it's inconsistent in
> > > > the code, too. I am not sure if it is possible to provide a negative
> > > > Duration? If not, we would not need to check the provided value and can
> > > > remove the declaration.
> > > > 
> > > > (2) About punctuations: I still think, it would be ok to change the
> > > > callback from `long` to `Instance` -- even if it is possible to register
> > > > a punctuation on a ms-basis, in practice many people used schedules in
> > > > the range of seconds or larger. Thus, I don't think there will be a
> > > > performance penalty. Of course, we can still revisit this later, too.
> > > > John and Bill, you did not comment on this. Would also be good to get
> > > > feedback from Guozhang about this.
> > > > 
> > > > (3) ReadOnlyWindowStore: All three methods are dual use and I think we
> > > > should not deprecate them. However, we can add the new proposed methods
> > > > in parallel -- the names can be the same without conflict as the
> > > > parameter lists are different. (Or did you just forget to remove the
> > > > comment line?)
> > > > 
> > > > (4) Stores: 3 methods are listed as deprecated but only 2 new methods
> > > > are added. Maybe this was discussed already, but I can't recall why? Can
> > > > you elaborate? Or should this deprecation be actually be part of KIP-328
> > > > (\cc John)?
> > > > 
> > > > 
> > > > Thanks,
> > > > 
> > > > -Matthias
> > > > 
> > > > 
> > > > 
> > > > ps: there are many KIPs in-flight in parallel, and it takes some time to
> > > > get around. Please be patient :)
> > > > 
> > > > 
> > > > 
> > > > 
> > > > On 9/5/18 12:25 AM, Nikolay Izhikov wrote:
> > > > > Hello, Guys.
> > > > > 
> > > > > I've started a VOTE [1], but seems commiters have no chance to look at
> > > 
> > > KIP for now.
> > > > > 
> > > > > Can you tell me, is it OK?
> > > > > Should I wait for feedback? For how long?
> > > > > 
> > > > > Or something in KIP should be improved before voting?
> > > > > 
> > > > > [1]
> > > 
> > > https://lists.apache.org/thread.html/e976352e7e42d459091ee66ac790b6a0de7064eac0c57760d50c983b@%3Cdev.kafka.apache.org%3E
> > > > > 
> > > > > В Пт, 24/08/2018 в 10:36 -0700, Matthias J. Sax пишет:
> > > > > > It's tricky... :)
> > > > > > 
> > > > > > Some APIs have "dual use" as I mentioned in my first reply. I agree
> > > 
> > > that
> > > > > > it would be good to avoid abstract class and use interfaces if
> > > 
> > > possible.
> > > > > > As long as the change is source code compatible, it should be fine
> > > 
> > > IMHO
> > > > > > -- we need to document binary incompatibility of course.
> > > > > > 
> > > > > > I think it's best, if the KIPs gets update with a proposal on how to
> > > > > > handle "dual use" parts. It's easier to discuss if it's written down
> > > 
> > > IMHO.
> > > > > > 
> > > > > > For `ProcessorContext#schedule()`, you are right John: it's seems
> > > 
> > > fine
> > > > > > to use `Duration`, as it won't be called often (usually only within
> > > > > > `Processor#init()`) -- I mixed it up with
> > > 
> > > `Punctuator#punctuate(long)`.
> > > > > > However, thinking about this twice, we might even want to update 
> > > > > > both
> > > > > > methods. Punctuation callbacks don't happen every millisecond and
> > > 
> > > thus
> > > > > > the overhead to use `Instance` should not be a problem.
> > > > > > 
> > > > > > @Nikolay: it seems the KIP does not mention
> > > 
> > > `Punctuator#punctuate(long)`
> > > > > > -- should we add it?
> > > > > > 
> > > > > > 
> > > > > > -Matthias
> > > > > > 
> > > > > > 
> > > > > > On 8/24/18 10:11 AM, John Roesler wrote:
> > > > > > > Quick afterthought: I guess that `Window` is exposed to the API 
> > > > > > > via
> > > > > > > `Windowed` keys. I think it would be fine to not deprecate the
> > > 
> > > `long` start
> > > > > > > and end, but add `Instant` variants for people preferring that
> > > 
> > > interface.
> > > > > > > 
> > > > > > > On Fri, Aug 24, 2018 at 11:10 AM John Roesler <j...@confluent.io>
> > > 
> > > wrote:
> > > > > > > 
> > > > > > > > Hey Matthias,
> > > > > > > > 
> > > > > > > > Thanks for pointing that out. I agree that we only really need
> > > 
> > > to change
> > > > > > > > methods that are API-facing, and we probably want to avoid using
> > > > > > > > Duration/Instant for Streams-facing members.
> > > > > > > > 
> > > > > > > > Like I said in my last email, I think the whole Windows
> > > 
> > > interface is
> > > > > > > > Streams-facing, and the builders we provide are otherwise
> > > 
> > > API-facing.
> > > > > > > > Likewise, `Window` is Streams-facing, so start and end should
> > > 
> > > not use
> > > > > > > > Duration. In SessionWindows, inactivityGap is Streams-facing.
> > > > > > > > 
> > > > > > > > I actually think that ProcessorContext#schedule() is API-facing,
> > > 
> > > so it
> > > > > > > > should use Duration. The rationale is that streams processing
> > > 
> > > doesn't call
> > > > > > > > this method, only implementer of Processor do. Does that seem
> > > 
> > > right?
> > > > > > > > 
> > > > > > > > Also, it seems like  ReadOnlyWindowStore#fetch() (2x) and
> > > 
> > > #fetchAll() are
> > > > > > > > API-facing (for IQ). When we call fetch() during processing,
> > > 
> > > it's actually
> > > > > > > > `WindowStore#fetch()`. Maybe we should move
> > > 
> > > "WindowStoreIterator<V> fetch(K
> > > > > > > > key, long timeFrom, long timeTo)" to the WindowStore interface
> > > 
> > > and make
> > > > > > > > all the ReadOnlyWindowStore methods take Durations. And likewise
> > > 
> > > with the
> > > > > > > > SessionStore interfaces.
> > > > > > > > 
> > > > > > > > What do you think?
> > > > > > > > 
> > > > > > > > Thanks,
> > > > > > > > -John
> > > > > > > > 
> > > > > > > > 
> > > > > > > > 
> > > > > > > > 
> > > > > > > > On Fri, Aug 24, 2018 at 10:51 AM John Roesler 
> > > > > > > > <j...@confluent.io>
> > > 
> > > wrote:
> > > > > > > > 
> > > > > > > > > Hi Nikolay,
> > > > > > > > > 
> > > > > > > > > First: I wanted to let you know that we have dropped the
> > > 
> > > `grace(long)`
> > > > > > > > > method from the Windows interface, but we do still need to
> > > 
> > > transition the
> > > > > > > > > same method on TimeWindows and JoinWindows (
> > > > > > > > > https://github.com/apache/kafka/pull/5536)
> > > > > > > > > 
> > > > > > > > > I have also been thinking it would be nice to replace
> > > 
> > > `Windows` with an
> > > > > > > > > interface, but for different reasons. I think we can even do
> > > 
> > > it without
> > > > > > > > > breaking source compatibility (but it would break binary
> > > 
> > > compatibility):
> > > > > > > > > create a new interface `WindowSpec`, deprecate `Windows` and
> > > 
> > > make it
> > > > > > > > > implement `WindowSpec`, add a new method:
> > > > > > > > > `KGroupedStream#windowedBy(WindowSpec)`, and deprecate the old
> > > 
> > > one.
> > > > > > > > > 
> > > > > > > > > However, I don't think this would solve your problem, since
> > > 
> > > the Windows
> > > > > > > > > interface has two audiences: the DSL user and the implementer
> > > 
> > > who wishes to
> > > > > > > > > provide a new kind of windowing. I think we want to provide
> > > 
> > > Duration to the
> > > > > > > > > former, and long or Duration is fine for the latter. However,
> > > 
> > > both of these
> > > > > > > > > audiences are "external", so having an "internal" interface
> > > 
> > > won't fit the
> > > > > > > > > bill.
> > > > > > > > > 
> > > > > > > > > I think my last PR #5536 actually helps the situation quite a
> > > 
> > > bit. Let's
> > > > > > > > > forget about the deprecated members. Now, all the public
> > > 
> > > members of Windows
> > > > > > > > > are abstract methods, so Windows is effectively an interface
> > > 
> > > now. Here's
> > > > > > > > > how it looks:
> > > > > > > > > 
> > > > > > > > > public abstract class Windows<W extends Window> {
> > > > > > > > > public abstract Map<Long, W> windowsFor(final long timestamp);
> > > > > > > > > public abstract long size();
> > > > > > > > > public abstract long gracePeriodMs();
> > > > > > > > > }
> > > > > > > > > 
> > > > > > > > > Notice that there is no part of this involved with the DSL.
> > > 
> > > When you're
> > > > > > > > > writing a topology, you don't call any of these methods. It's
> > > 
> > > strictly an
> > > > > > > > > interface that tells a Windows implementation what Streams
> > > 
> > > expects from it.
> > > > > > > > > A very simple implementation could have no builder methods at
> > > 
> > > all and just
> > > > > > > > > return fixed answers to these method calls (this is basically
> > > 
> > > what
> > > > > > > > > UnlimitedWindows does). It seems like, if we want to use long
> > > 
> > > millis
> > > > > > > > > internally, then we just need to leave Windows alone.
> > > > > > > > > 
> > > > > > > > > What we do want to change is the builder methods in
> > > 
> > > TimeWindows,
> > > > > > > > > JoinWindows, and UnlimitedWindows. For example,
> > > 
> > > `TimeWindows#of(long)`
> > > > > > > > > would become `TimeWindows#of(Duration)`, etc. These are the
> > > 
> > > DSL methods.
> > > > > > > > > 
> > > > > > > > > Does that make sense?
> > > > > > > > > -John
> > > > > > > > > 
> > > > > > > > > 
> > > > > > > > > 
> > > > > > > > > On Thu, Aug 23, 2018 at 8:59 AM Nikolay Izhikov <
> > > 
> > > nizhi...@apache.org>
> > > > > > > > > wrote:
> > > > > > > > > 
> > > > > > > > > > Hello, Mathias.
> > > > > > > > > > 
> > > > > > > > > > Thanks for your feedback.
> > > > > > > > > > 
> > > > > > > > > > > Thus, it might make sense to keep old and just add new
> > > 
> > > ones?
> > > > > > > > > > 
> > > > > > > > > > As far as I understand, we will keep old methods anyway to
> > > 
> > > prevent
> > > > > > > > > > public API backward compatibility.
> > > > > > > > > > I agree with you, methods that used internally shouldn't be
> > > 
> > > deprecated.
> > > > > > > > > > 
> > > > > > > > > > > End users can use the "nicer" new ones, while we can still
> > > 
> > > use the
> > > > > > > > > > 
> > > > > > > > > > existing ones internally?
> > > > > > > > > > > Not sure if it would be possible to keep the old ones
> > > 
> > > without exposing
> > > > > > > > > > 
> > > > > > > > > > them as public API?
> > > > > > > > > > 
> > > > > > > > > > I think, when we decide to remove methods with `long` from
> > > 
> > > public API,
> > > > > > > > > > we can do the following:
> > > > > > > > > > 
> > > > > > > > > > 1. Create an interface like `WindowsInternal`.
> > > > > > > > > > 2. Change Windows to an interface.
> > > > > > > > > > 3. Create package-private implementation `WindowsImpl`.
> > > > > > > > > > 
> > > > > > > > > > ```
> > > > > > > > > >         package org.apache.kafka.streams.kstream.internals;
> > > > > > > > > >         public interface WindowsInternal {
> > > > > > > > > >                 public long start();
> > > > > > > > > >                 public long end();
> > > > > > > > > >                 //etc...
> > > > > > > > > >         }
> > > > > > > > > > 
> > > > > > > > > >         package org.apache.kafka.streams.kstream;
> > > > > > > > > >         public interface Windows<W extends Window> {
> > > > > > > > > >                 public Instant start();
> > > > > > > > > >                 public Instant end();
> > > > > > > > > >                 //...
> > > > > > > > > >         }
> > > > > > > > > > 
> > > > > > > > > >         class WindowsImpl<W extends Window> implements
> > > 
> > > Windows<W>,
> > > > > > > > > > WindowsInternal {
> > > > > > > > > > 
> > > > > > > > > >         }
> > > > > > > > > > ```
> > > > > > > > > > 
> > > > > > > > > > So, in public API we will expose only `Windows` interface
> > > 
> > > and internally
> > > > > > > > > > we can use `WindowsInternal`
> > > > > > > > > > But, of course, this will be huge changes in public API.
> > > > > > > > > > 
> > > > > > > > > > > Let me know what you think about this.
> > > > > > > > > > 
> > > > > > > > > > I think in this KIP we shouldn't deprecate methods, that are
> > > 
> > > used
> > > > > > > > > > internally.
> > > > > > > > > > I changed it, now my proposal is just add new methods.
> > > > > > > > > > 
> > > > > > > > > > Please, let me know if anything more need to be done.
> > > > > > > > > > 
> > > > > > > > > > В Ср, 22/08/2018 в 17:29 -0700, Matthias J. Sax пишет:
> > > > > > > > > > > Thanks a lot for the KIP.
> > > > > > > > > > > 
> > > > > > > > > > > From my understanding, the idea of the KIP is to improve
> > > 
> > > the public API
> > > > > > > > > > > at DSL level. However, not all public methods listed are
> > > 
> > > part of DSL
> > > > > > > > > > > level API, but part of runtime API. Those methods are
> > > 
> > > called during
> > > > > > > > > > > processing and are on the hot code path. I am not sure, if
> > > 
> > > we want to
> > > > > > > > > > > update those methods. We should carefully think about
> > > 
> > > this, and
> > > > > > > > > > 
> > > > > > > > > > consider
> > > > > > > > > > > to keep Long/long type to keep runtime overhead small.
> > > 
> > > Note, that the
> > > > > > > > > > > methods I mention are not required to specify a program
> > > 
> > > using the DSL
> > > > > > > > > > > and thus is questionable if the DSL API would be improved
> > > 
> > > if we change
> > > > > > > > > > > the methods.
> > > > > > > > > > > 
> > > > > > > > > > > It's unfortunate, that some part of the public API stretch
> > > 
> > > the DSL
> > > > > > > > > > > builder part as well as the runtime part...
> > > > > > > > > > > 
> > > > > > > > > > > This affects the following methods (please double check if
> > > 
> > > I missed
> > > > > > > > > > 
> > > > > > > > > > any):
> > > > > > > > > > > 
> > > > > > > > > > >  - Windows#windowsFor()
> > > > > > > > > > >  - Window#start()
> > > > > > > > > > >  - Window#end()
> > > > > > > > > > >  - JoinWindows#windowFor()
> > > > > > > > > > >  - SessionWindows#inactivitiyGap()
> > > > > > > > > > >  - TimeWindows#windowFor()
> > > > > > > > > > >  - UnlimitedWindows#windowFor()
> > > > > > > > > > >  - ProcessorContext#schedule()
> > > > > > > > > > >  - ReadOnlyWindowStore#fetch() (2x) and #fetchAll()
> > > > > > > > > > >  - SessionStore#findSessions() (2x)
> > > > > > > > > > > 
> > > > > > > > > > > maybe
> > > > > > > > > > >  - TimeWindowedDeserializer#getWindowSize() (it's unused
> > > 
> > > atm, but I
> > > > > > > > > > > could imagine that it might be use on the hot code path in
> > > 
> > > the furture)
> > > > > > > > > > > 
> > > > > > > > > > > So methods have "dual" use and might be called externally
> > > 
> > > and
> > > > > > > > > > 
> > > > > > > > > > internally:
> > > > > > > > > > > 
> > > > > > > > > > >  - Window#start()
> > > > > > > > > > >  - Window#end()
> > > > > > > > > > >  - ReadOnlyWindowStore#fetch() (2x) and #fetchAll()
> > > > > > > > > > >  - SessionStore#findSessions() (2x)
> > > > > > > > > > > 
> > > > > > > > > > > Thus, it might make sense to keep old and just add new
> > > 
> > > ones? End users
> > > > > > > > > > > can use the "nicer" new ones, while we can still use the
> > > 
> > > existing ones
> > > > > > > > > > > internally? Not sure if it would be possible to keep the
> > > 
> > > old ones
> > > > > > > > > > > without exposing them as public API?
> > > > > > > > > > > 
> > > > > > > > > > > Let me know what you think about this.
> > > > > > > > > > > 
> > > > > > > > > > > 
> > > > > > > > > > > -Matthias
> > > > > > > > > > > 
> > > > > > > > > > > 
> > > > > > > > > > > 
> > > > > > > > > > > On 8/21/18 11:41 PM, Nikolay Izhikov wrote:
> > > > > > > > > > > > Dear, commiters.
> > > > > > > > > > > > 
> > > > > > > > > > > > Please, pay attention to this KIP and share your 
> > > > > > > > > > > > opinion.
> > > > > > > > > > > > 
> > > > > > > > > > > > В Вт, 21/08/2018 в 11:14 -0500, John Roesler пишет:
> > > > > > > > > > > > > I'll solicit more reviews. Let's get at least one
> > > 
> > > committer to
> > > > > > > > > > 
> > > > > > > > > > chime in
> > > > > > > > > > > > > before we start a vote (since we need their approval
> > > 
> > > anyway).
> > > > > > > > > > > > > -John
> > > > > > > > > > > > > 
> > > > > > > > > > > > > On Mon, Aug 20, 2018 at 12:39 PM Nikolay Izhikov <
> > > > > > > > > > 
> > > > > > > > > > nizhi...@apache.org>
> > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > 
> > > > > > > > > > > > > > Hello, Ted.
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > Thanks for the comment.
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > I've edit KIP and change proposal to `windowSize`.
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > Guys, any other comments?
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > В Вс, 19/08/2018 в 14:57 -0700, Ted Yu пишет:
> > > > > > > > > > > > > > > bq. // or just Duration windowSize();
> > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > +1 to the above choice.
> > > > > > > > > > > > > > > The duration is obvious from the return type. For
> > > 
> > > getter
> > > > > > > > > > 
> > > > > > > > > > methods, we
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > don't
> > > > > > > > > > > > > > > use get as prefix (as least for new code).
> > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > Cheers
> > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > On Sun, Aug 19, 2018 at 8:03 AM Nikolay Izhikov <
> > > > > > > > > > 
> > > > > > > > > > nizhi...@apache.org>
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > Hello, John.
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > Thank you very much for your feedback!
> > > > > > > > > > > > > > > > I've addressed all your comments.
> > > > > > > > > > > > > > > > Please, see my answers and let my know is
> > > 
> > > anything in KIP
> > > > > > > > > > 
> > > > > > > > > > [1] needs to
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > improved.
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > The correct choice is actually "Instant", not>
> > > > > > > > > > 
> > > > > > > > > > "LocalDateTime"
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > I've changed the methods proposed in KIP [1] to
> > > 
> > > use Instant.
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > I noticed some recent APIs are> missing (see
> > > 
> > > KIP-328)
> > > > > > > > > > > > > > > > > those APIs were just added and have never been
> > > 
> > > released...
> > > > > > > > > > 
> > > > > > > > > > you can
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > just
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > replace them.
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > I've added new methods to KIP [1].
> > > > > > > > > > > > > > > > Not released methods marked for remove.
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > any existing method that's already deprecated,
> > > 
> > > don't bother
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > transitioning it to Duration.
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > Fixed.
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > IllegalArgumentException... we should plan to
> > > 
> > > mention this
> > > > > > > > > > 
> > > > > > > > > > in the
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > javadoc for those methods.
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > Got it.
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > In Stores, windowSize and segmentInterval
> > > 
> > > should also be
> > > > > > > > > > 
> > > > > > > > > > durations.
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > Fixed.
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > StreamsMetrics, recordLatency ... this one is
> > > 
> > > better left
> > > > > > > > > > 
> > > > > > > > > > alone.
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > OK. I removed this method from KIP [1].
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > Two more questions question about 
> > > > > > > > > > > > > > > > implementation:
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > 1. We have serveral methods without parameters.
> > > > > > > > > > > > > > > > In java we can't have two methods with
> > > 
> > > parameters with the
> > > > > > > > > > 
> > > > > > > > > > same name.
> > > > > > > > > > > > > > > > It wouldn't compile.
> > > > > > > > > > > > > > > > So we have to rename new methods. Please, see
> > > 
> > > suggested
> > > > > > > > > > 
> > > > > > > > > > names and share
> > > > > > > > > > > > > > > > your thoughts:
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > Windows {
> > > > > > > > > > > > > > > >     long size() -> Duration windowSize();
> > > > > > > > > > > > > > > > }
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > Window {
> > > > > > > > > > > > > > > >     long start() -> Instant startTime();
> > > > > > > > > > > > > > > >     long end() -> Instant endTime();
> > > > > > > > > > > > > > > > }
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > SessionWindows {
> > > > > > > > > > > > > > > >     long inactivityGap() -> Duration
> > > 
> > > inactivityGapDuration();
> > > > > > > > > > > > > > > > }
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > TimeWindowedDeserializer {
> > > > > > > > > > > > > > > >     Long getWindowSize() -> Duration
> > > > > > > > > > 
> > > > > > > > > > getWindowSizeDuration(); // or
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > just
> > > > > > > > > > > > > > > > Duration windowSize();
> > > > > > > > > > > > > > > > }
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > SessionBytesStoreSupplier {
> > > > > > > > > > > > > > > >     long retentionPeriod() -> Duration
> > > > > > > > > > 
> > > > > > > > > > retentionPeriodDuration();
> > > > > > > > > > > > > > > > }
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > WindowBytesStoreSupplier {
> > > > > > > > > > > > > > > >     long windowSize() -> Duration
> > > 
> > > windowSizeDuration();
> > > > > > > > > > > > > > > >     long retentionPeriod() -> Duration
> > > > > > > > > > 
> > > > > > > > > > retentionPeriodDuration();
> > > > > > > > > > > > > > > > }
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > 2. Do we want to use Duration and Instant inside
> > > 
> > > API
> > > > > > > > > > 
> > > > > > > > > > implementations?
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > IGNITE-7277: "Durations potentially worsen
> > > 
> > > memory pressure
> > > > > > > > > > 
> > > > > > > > > > and gc
> > > > > > > > > > > > > > > > performance, so internally, we will still use
> > > 
> > > longMs as the
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > representation."
> > > > > > > > > > > > > > > > IGNITE-7222: Duration used to store retention.
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > [1]
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > 
> > > > > > > > > > 
> > > > > > > > > > 
> > > 
> > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-358%3A+Migrate+Streams+API+to+Duration+instead+of+long+ms+times
> > > > > > > > > > > > > > > > [2]
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > 
> > > > > > > > > > 
> > > > > > > > > > 
> > > 
> > > https://github.com/apache/kafka/commit/b3771ba22acad7870e38ff7f58820c5b50946787#diff-47289575d3e3e2449f27b3a7b6788e1aR64
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > В Пт, 17/08/2018 в 14:46 -0500, John Roesler
> > > 
> > > пишет:
> > > > > > > > > > > > > > > > > Hi Nikolay,
> > > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > Thanks for this very nice KIP!
> > > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > To answer your questions:
> > > > > > > > > > > > > > > > > 1. Correct, we should not delete existing
> > > 
> > > methods that
> > > > > > > > > > 
> > > > > > > > > > have been
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > released,
> > > > > > > > > > > > > > > > > but ...
> > > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > 2. Yes, we should deprecate the 'long'
> > > 
> > > variants so that we
> > > > > > > > > > 
> > > > > > > > > > can drop
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > them
> > > > > > > > > > > > > > > > > later on. Personally, I like to mention which
> > > 
> > > version
> > > > > > > > > > 
> > > > > > > > > > deprecated the
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > method
> > > > > > > > > > > > > > > > > so everyone can see later on how long it's 
> > > > > > > > > > > > > > > > > been
> > > > > > > > > > 
> > > > > > > > > > deprecated, but this
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > may
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > controversial, so let's let other weigh in.
> > > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > 3. I think you're asking whether it's
> > > 
> > > appropriate to drop
> > > > > > > > > > 
> > > > > > > > > > the "Ms"
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > suffix,
> > > > > > > > > > > > > > > > > and I think yes. So "long inactivityGapMs"
> > > 
> > > would become
> > > > > > > > > > 
> > > > > > > > > > "Duration
> > > > > > > > > > > > > > > > > inactivityGap".
> > > > > > > > > > > > > > > > > In the places where the parameter's name is
> > > 
> > > just
> > > > > > > > > > 
> > > > > > > > > > "duration", I think
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > we
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > can
> > > > > > > > > > > > > > > > > pick something more descriptive (I realize it
> > > 
> > > was already
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > "durationMs";
> > > > > > > > > > > > > > > > > this is just a good time to improve it).
> > > > > > > > > > > > > > > > > Also, you're correct that we shouldn't use a
> > > 
> > > Duration to
> > > > > > > > > > 
> > > > > > > > > > represent a
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > moment
> > > > > > > > > > > > > > > > > in time, like "startTime". The correct choice
> > > 
> > > is actually
> > > > > > > > > > 
> > > > > > > > > > "Instant",
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > not
> > > > > > > > > > > > > > > > > "LocalDateTime", though.
> > > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > 
> > > > > > > > > > 
> > > > > > > > > > 
> > > 
> > > https://stackoverflow.com/questions/32437550/whats-the-difference-between-instant-and-localdatetime
> > > > > > > > > > > > > > > > > explains why.
> > > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > I also had a few notes on the KIP itself:
> > > > > > > > > > > > > > > > > 4. You might want to pull trunk again. I
> > > 
> > > noticed some
> > > > > > > > > > 
> > > > > > > > > > recent APIs are
> > > > > > > > > > > > > > > > > missing (see KIP-328).
> > > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > 5. Speaking of KIP-328: those APIs were just
> > > 
> > > added and
> > > > > > > > > > 
> > > > > > > > > > have never
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > been
> > > > > > > > > > > > > > > > > released, so there's no need to deprecate the
> > > 
> > > methods, you
> > > > > > > > > > 
> > > > > > > > > > can just
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > replace
> > > > > > > > > > > > > > > > > them.
> > > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > 6. For any existing method that's already
> > > 
> > > deprecated,
> > > > > > > > > > 
> > > > > > > > > > don't bother
> > > > > > > > > > > > > > > > > transitioning it to Duration. I think the
> > > 
> > > examples I
> > > > > > > > > > 
> > > > > > > > > > noticed were
> > > > > > > > > > > > > > > > > deprecated in KIP-328, so you'll see what I'm
> > > 
> > > talking
> > > > > > > > > > 
> > > > > > > > > > about when you
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > pull
> > > > > > > > > > > > > > > > > trunk again.
> > > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > 7. Any method taking a Duration argument may
> > > 
> > > throw an
> > > > > > > > > > > > > > > > > IllegalArgumentException (we choose to convert
> > > > > > > > > > 
> > > > > > > > > > ArithmeticException to
> > > > > > > > > > > > > > > > > IllegalArgumentException, as I mentioned in
> > > 
> > > the Jira
> > > > > > > > > > 
> > > > > > > > > > ticket). We
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > don't
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > need
> > > > > > > > > > > > > > > > > a "throws" declaration, but we should plan to
> > > 
> > > mention this
> > > > > > > > > > 
> > > > > > > > > > in the
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > javadoc
> > > > > > > > > > > > > > > > > for those methods.
> > > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > 8. In Stores, windowSize and segmentInterval
> > > 
> > > should also be
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > durations.
> > > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > 9. In StreamsMetrics, recordLatency could be
> > > 
> > > just a
> > > > > > > > > > 
> > > > > > > > > > Duration, but I
> > > > > > > > > > > > > > > > > actually think this one is better left alone.
> > > 
> > > IMO, it's
> > > > > > > > > > 
> > > > > > > > > > more effort
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > little gain to require users to construct a
> > > 
> > > Duration
> > > > > > > > > > 
> > > > > > > > > > before they
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > call the
> > > > > > > > > > > > > > > > > method, since they vary likely call
> > > > > > > > > > 
> > > > > > > > > > System.currentTimeNanos before
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > after the code in question.
> > > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > These are quite a few notes, but they're all
> > > 
> > > minor.
> > > > > > > > > > 
> > > > > > > > > > Overall the KIP
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > looks
> > > > > > > > > > > > > > > > > really good to me. Thanks for picking this up!
> > > > > > > > > > > > > > > > > -John
> > > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > On Thu, Aug 16, 2018 at 9:55 AM Nikolay
> > > 
> > > Izhikov <
> > > > > > > > > > 
> > > > > > > > > > nizhi...@apache.org
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > > Hello, Kafka developers.
> > > > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > > I would like to start a discussion of
> > > 
> > > KIP-358 [1].
> > > > > > > > > > > > > > > > > > It based on a ticket KAFKA-7277 [2].
> > > > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > > I crawled through Stream API and made my
> > > 
> > > suggestions for
> > > > > > > > > > 
> > > > > > > > > > API
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > changes.
> > > > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > > I have several questions about changes.
> > > > > > > > > > > > > > > > > > Please, share your comments:
> > > > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > > 1. I propose do not remove existing API
> > > 
> > > methods with
> > > > > > > > > > 
> > > > > > > > > > long ms
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > parameters.
> > > > > > > > > > > > > > > > > > Is it correct?
> > > > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > > 2. Should we mark existing methods as
> > > 
> > > deprecated?
> > > > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > > 3. Suggested changes in ticket description
> > > 
> > > are `long
> > > > > > > > > > 
> > > > > > > > > > durationMs` to
> > > > > > > > > > > > > > > > > > `Duration duration` and similar.
> > > > > > > > > > > > > > > > > > I suggest to change 'long startTimeMs` to
> > > 
> > > `LocalDateTime
> > > > > > > > > > 
> > > > > > > > > > startTime`
> > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > also.
> > > > > > > > > > > > > > > > > > Should we do it?
> > > > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > > Please, note, it very first KIP for me, so
> > > 
> > > tell me if I
> > > > > > > > > > 
> > > > > > > > > > miss
> > > > > > > > > > > > > > 
> > > > > > > > > > > > > > something
> > > > > > > > > > > > > > > > > > obvious for experienced Kafka developers.
> > > > > > > > > > > > > > > > > > 
> > > > > > > > > > > > > > > > > > [1]
> > > > > > > > > > > > > > > > > > 
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> > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-358%3A+Migrate+Streams+API+to+Duration+instead+of+long+ms+times
> > > > > > > > > > > > > > > > > > [2]
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> > > https://issues.apache.org/jira/browse/KAFKA-7277
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