Hi Aljoscha, Can you point us to the way it is handled now. Is there anything else for the removing of elements other than the skip in EvictingWindowOperator. Is there something as it was before version 1.x where you had an explicit remove from window buffers?
Dr. Radu Tudoran Research Engineer - Big Data Expert IT R&D Division HUAWEI TECHNOLOGIES Duesseldorf GmbH European Research Center Riesstrasse 25, 80992 München E-mail: radu.tudo...@huawei.com Mobile: +49 15209084330 Telephone: +49 891588344173 HUAWEI TECHNOLOGIES Duesseldorf GmbH Hansaallee 205, 40549 Düsseldorf, Germany, www.huawei.com Registered Office: Düsseldorf, Register Court Düsseldorf, HRB 56063, Managing Director: Bo PENG, Wanzhou MENG, Lifang CHEN Sitz der Gesellschaft: Düsseldorf, Amtsgericht Düsseldorf, HRB 56063, Geschäftsführer: Bo PENG, Wanzhou MENG, Lifang CHEN This e-mail and its attachments contain confidential information from HUAWEI, which is intended only for the person or entity whose address is listed above. Any use of the information contained herein in any way (including, but not limited to, total or partial disclosure, reproduction, or dissemination) by persons other than the intended recipient(s) is prohibited. If you receive this e-mail in error, please notify the sender by phone or email immediately and delete it! -----Original Message----- From: Aljoscha Krettek [mailto:aljos...@apache.org] Sent: Monday, July 25, 2016 11:45 AM To: dev@flink.apache.org Subject: Re: [DISCUSS][FLIP-4] Enhance Window Evictor in Flink Hi, I think there is not yet a clear specification for how the actual removal of elements from the buffer will work. I think naively one can do: Iterable<E> currentElements = state.get() evictor.evict(currentElements); // this will remove some stuff from there, or mark for removal state.clear() // the Iterable does not loop over the removed/marked elements for (E element : currentElements) { state.add(element) } This is very costly but the only way I see of doing this right now with every state backend. Cheers, Aljoscha On Mon, 25 Jul 2016 at 09:46 Radu Tudoran <radu.tudo...@huawei.com> wrote: > Hi, > > Thanks for the clarification. Can someone point to where the events are > removed from buffers - I am trying to understand the new logic of handling > the eviction in this new API. Thanks > > > > -----Original Message----- > From: Vishnu Viswanath [mailto:vishnu.viswanat...@gmail.com] > Sent: Saturday, July 23, 2016 3:04 AM > To: Dev > Subject: Re: [DISCUSS][FLIP-4] Enhance Window Evictor in Flink > > Hi Radu, > > - Yes we can remove elements from the iterator. > - Right now the EvictingWindowOperator just skips the elements from the > Iterable before passing to the window function(Yes this has to be changed > in the new API) > - Regarding how the last question on how elements are being removed from > the window buffer. I am not sure how it is working right now, but when > trying out the new API that I am working on, I did find a bug where the > evicted elements are not actually removed from the State. I have added a > fix for that. (You can see a mail regarding that in this mail chain) > > Thanks, > Vishnu > > On Fri, Jul 22, 2016 at 1:03 PM, Radu Tudoran <radu.tudo...@huawei.com> > wrote: > > > Hi, > > > > Overall I believe that the interfaces and the proposal is good. I have > the > > following question though: can you delete via the iterator > > (Iterable<StreamRecord<T>> elements) the elements? > > > > I tried to look over the code where the eviction happens (I did not do > > these since version 0.10...looks very different now :) )...the only > > reference I found was the EvictingWindowOperator which at the > > fireOrContinue has a "skip" based on the number of elements returned from > > the evictor...and these are not put in the collection to be given to the > > user function to be applied. I think these will also need to be changed > to > > adjust to the "any operator from anywhere in the window buffer". > > Also - as we are on this topic - can someone explain how these elements > > that are not consider anymore for the user function are actually deleted > > from the window buffer?..i did not manage to find this.. some reference > to > > classes/code where this happens would be useful > > > > > > Dr. Radu Tudoran > > Research Engineer - Big Data Expert > > IT R&D Division > > > > > > HUAWEI TECHNOLOGIES Duesseldorf GmbH > > European Research Center > > Riesstrasse 25, 80992 München > > > > E-mail: radu.tudo...@huawei.com > > Mobile: +49 15209084330 > > Telephone: +49 891588344173 > > > > HUAWEI TECHNOLOGIES Duesseldorf GmbH > > Hansaallee 205, 40549 Düsseldorf, Germany, www.huawei.com > > Registered Office: Düsseldorf, Register Court Düsseldorf, HRB 56063, > > Managing Director: Bo PENG, Wanzhou MENG, Lifang CHEN > > Sitz der Gesellschaft: Düsseldorf, Amtsgericht Düsseldorf, HRB 56063, > > Geschäftsführer: Bo PENG, Wanzhou MENG, Lifang CHEN > > This e-mail and its attachments contain confidential information from > > HUAWEI, which is intended only for the person or entity whose address is > > listed above. Any use of the information contained herein in any way > > (including, but not limited to, total or partial disclosure, > reproduction, > > or dissemination) by persons other than the intended recipient(s) is > > prohibited. If you receive this e-mail in error, please notify the sender > > by phone or email immediately and delete it! > > > > > > -----Original Message----- > > From: Vishnu Viswanath [mailto:vishnu.viswanat...@gmail.com] > > Sent: Friday, July 22, 2016 12:43 PM > > To: Dev > > Subject: Re: [DISCUSS][FLIP-4] Enhance Window Evictor in Flink > > > > Hi, > > > > I have created a FLIP page for this enhancement > > > > > https://cwiki.apache.org/confluence/display/FLINK/FLIP-4+%3A+Enhance+Window+Evictor > > > > Thanks, > > Vishnu > > > > On Thu, Jul 21, 2016 at 6:53 AM, Vishnu Viswanath < > > vishnu.viswanat...@gmail.com> wrote: > > > > > Thanks Aljoscha. > > > > > > On Thu, Jul 21, 2016 at 4:46 AM, Aljoscha Krettek <aljos...@apache.org > > > > > wrote: > > > > > >> Hi, > > >> this, in fact, seems to be a bug. There should be something like > > >> windowState.clear(); > > >> for (IN element: projectedContents) { > > >> windowState.add(element); > > >> } > > >> > > >> after passing the elements to the window function. > > >> > > >> This is very inefficient but the only way I see of doing it right now. > > >> > > >> Cheers, > > >> Aljoscha > > >> > > >> > > >> On Thu, 21 Jul 2016 at 01:32 Vishnu Viswanath < > > >> vishnu.viswanat...@gmail.com> > > >> wrote: > > >> > > >> > Hi, > > >> > > > >> > When we use RocksDB as state backend, how does the backend state get > > >> > updated after some elements are evicted from the window? > > >> > I don't see any update call being made to remove the element from > the > > >> state > > >> > stored in RocksDB. > > >> > > > >> > It looks like the RocksDBListState is only having get() and add() > > >> methods > > >> > since it is an AppendingState, but that causes the evicted elements > to > > >> come > > >> > back when the trigger is fired next time. (It works fine when I use > > >> > MemoryStateBackend) > > >> > > > >> > Is this expected behavior or am I missing something. > > >> > > > >> > Thanks, > > >> > Vishnu > > >> > > > >> > On Mon, Jul 18, 2016 at 7:15 AM, Vishnu Viswanath < > > >> > vishnu.viswanat...@gmail.com> wrote: > > >> > > > >> > > Hi Aljoscha, > > >> > > > > >> > > Thanks! Yes, I have the create page option now in wiki. > > >> > > > > >> > > Regards, > > >> > > Vishnu Viswanath, > > >> > > > > >> > > On Mon, Jul 18, 2016 at 6:34 AM, Aljoscha Krettek < > > >> aljos...@apache.org> > > >> > > wrote: > > >> > > > > >> > >> @Radu, addition of more window types and sorting should be part > of > > >> > another > > >> > >> design proposal. This is interesting stuff but I think we should > > keep > > >> > >> issues separated because things can get complicated very quickly. > > >> > >> > > >> > >> On Mon, 18 Jul 2016 at 12:32 Aljoscha Krettek < > aljos...@apache.org > > > > > >> > >> wrote: > > >> > >> > > >> > >> > Hi, > > >> > >> > about TimeEvictor, yes, I think there should be specific > evictors > > >> for > > >> > >> > processing time and event time. Also, the current time should > be > > >> > >> > retrievable from the EvictorContext. > > >> > >> > > > >> > >> > For the wiki you will need permissions. This was recently > changed > > >> > >> because > > >> > >> > there was too much spam. I gave you permission to add pages. > Can > > >> you > > >> > >> please > > >> > >> > try and check if it works? > > >> > >> > > > >> > >> > Cheers, > > >> > >> > Aljoscha > > >> > >> > > > >> > >> > On Fri, 15 Jul 2016 at 13:28 Vishnu Viswanath < > > >> > >> > vishnu.viswanat...@gmail.com> wrote: > > >> > >> > > > >> > >> >> Hi all, > > >> > >> >> > > >> > >> >> How do we create a FLIP page, is there any permission setup > > >> > required? I > > >> > >> >> don't see any "Create" page(after logging in) option in the > > >> header as > > >> > >> >> mentioned in > > >> > >> >> > > >> > >> >> > > >> > >> > > >> > > > >> > > > https://cwiki.apache.org/confluence/display/FLINK/Flink+Improvement+Proposals > > >> > >> >> > > >> > >> >> > > >> > >> >> Thanks, > > >> > >> >> Vishnu > > >> > >> >> > > >> > >> >> On Wed, Jul 13, 2016 at 10:22 PM, Vishnu Viswanath < > > >> > >> >> vishnu.viswanat...@gmail.com> wrote: > > >> > >> >> > > >> > >> >> > Hi Aljoscha, > > >> > >> >> > > > >> > >> >> > I agree, the user will know exactly that they are creating > an > > >> > >> EventTime > > >> > >> >> > based evictor or ProcessingTime based evictor looking at the > > >> code. > > >> > >> >> > So do you think it will be ok to have multiple versions of > > >> > >> TimeEvictor > > >> > >> >> > (one for event time and one for processing time) and also a > > >> > >> DeltaEvcitor > > >> > >> >> > (again 2 versions- for event time and processing time) ? > > >> > >> >> > > > >> > >> >> > Please note that the existing behavior of > > >> TimeEvictor/DeltaEvictor > > >> > >> does > > >> > >> >> > not consider if it is EventTime or ProcessingTime > > >> > >> >> > e.g., in TimeEvictor the current time is considered as the > > >> > timestamp > > >> > >> of > > >> > >> >> > the last element in the window > > >> > >> >> > > > >> > >> >> > *long currentTime = > > Iterables.getLast(elements).getTimestamp();* > > >> > >> >> > > > >> > >> >> > not the highest timestamp of all elements > > >> > >> >> > what I am trying to achieve is something like: > > >> > >> >> > > > >> > >> >> > *long currentTime;* > > >> > >> >> > * if (ctx.isEventTime()) {* > > >> > >> >> > * currentTime = getMaxTimestamp(elements);* > > >> > >> >> > * } else {* > > >> > >> >> > * currentTime = Iterables.getLast(elements).getTimestamp();* > > >> > >> >> > * }* > > >> > >> >> > > > >> > >> >> > Similarly, in DeltaEvictor the *`lastElement`* is > > >> > >> >> > *`Iterables.getLast(elements);`* and I am thinking we should > > >> > consider > > >> > >> >> the > > >> > >> >> > element with max timestamp as the last element instead of > just > > >> > >> getting > > >> > >> >> the > > >> > >> >> > last inserted element as *`lastElement`* > > >> > >> >> > > > >> > >> >> > Do you think it is the right thing to do or leave the > behavior > > >> > >> Evictors > > >> > >> >> as > > >> > >> >> > is, w.r.t to choosing the last element? > > >> > >> >> > > > >> > >> >> > Thanks, > > >> > >> >> > Vishnu > > >> > >> >> > > > >> > >> >> > On Wed, Jul 13, 2016 at 11:07 AM, Aljoscha Krettek < > > >> > >> aljos...@apache.org > > >> > >> >> > > > >> > >> >> > wrote: > > >> > >> >> > > > >> > >> >> >> I still think it should be explicit in the class. For > > example, > > >> if > > >> > >> you > > >> > >> >> have > > >> > >> >> >> this code: > > >> > >> >> >> > > >> > >> >> >> input > > >> > >> >> >> .keyBy() > > >> > >> >> >> .window() > > >> > >> >> >> .trigger(EventTimeTrigger.create()) > > >> > >> >> >> .evictor(TimeTrigger.create()) > > >> > >> >> >> > > >> > >> >> >> the time behavior of the trigger is explicitly specified > > while > > >> the > > >> > >> >> evictor > > >> > >> >> >> would dynamically adapt based on internal workings that the > > >> user > > >> > >> might > > >> > >> >> not > > >> > >> >> >> be aware of. Having the behavior explicit at the call site > is > > >> very > > >> > >> >> >> important, in my opinion. > > >> > >> >> >> > > >> > >> >> >> On Wed, 13 Jul 2016 at 16:28 Vishnu Viswanath < > > >> > >> >> >> vishnu.viswanat...@gmail.com> > > >> > >> >> >> wrote: > > >> > >> >> >> > > >> > >> >> >> > Hi, > > >> > >> >> >> > > > >> > >> >> >> > I was hoping to use the isEventTime method in the > > >> WindowAssigner > > >> > >> to > > >> > >> >> set > > >> > >> >> >> > that information in the EvictorContext. > > >> > >> >> >> > What do you think?. > > >> > >> >> >> > > > >> > >> >> >> > Thanks and Regards, > > >> > >> >> >> > Vishnu Viswanath, > > >> > >> >> >> > > > >> > >> >> >> > On Wed, Jul 13, 2016 at 10:09 AM, Aljoscha Krettek < > > >> > >> >> aljos...@apache.org > > >> > >> >> >> > > > >> > >> >> >> > wrote: > > >> > >> >> >> > > > >> > >> >> >> > > Hi, > > >> > >> >> >> > > I think the way to go here is to add both an > > >> EventTimeEvictor > > >> > >> and a > > >> > >> >> >> > > ProcessingTimeEvictor. The problem is that > "isEventTime" > > >> > cannot > > >> > >> >> >> really be > > >> > >> >> >> > > determined. That's also the reason why there is an > > >> > >> EventTimeTrigger > > >> > >> >> >> and a > > >> > >> >> >> > > ProcessingTimeTrigger. It was just an oversight that > the > > >> > >> >> TimeEvictor > > >> > >> >> >> does > > >> > >> >> >> > > not also have these two versions. > > >> > >> >> >> > > > > >> > >> >> >> > > About EvictingWindowOperator, I think you can make the > > two > > >> > >> methods > > >> > >> >> >> > > non-final in WindowOperator, yes. > > >> > >> >> >> > > > > >> > >> >> >> > > Cheers, > > >> > >> >> >> > > Aljoscha > > >> > >> >> >> > > > > >> > >> >> >> > > On Wed, 13 Jul 2016 at 14:32 Vishnu Viswanath < > > >> > >> >> >> > > vishnu.viswanat...@gmail.com> > > >> > >> >> >> > > wrote: > > >> > >> >> >> > > > > >> > >> >> >> > > > Hi Aljoscha, > > >> > >> >> >> > > > > > >> > >> >> >> > > > I am thinking of adding a method boolean > isEventTime(); > > >> in > > >> > the > > >> > >> >> >> > > > EvictorContext apart from > > >> > >> >> >> > > > > > >> > >> >> >> > > > long getCurrentProcessingTime(); > > >> > >> >> >> > > > MetricGroup getMetricGroup(); > > >> > >> >> >> > > > long getCurrentWatermark(); > > >> > >> >> >> > > > > > >> > >> >> >> > > > This method can be used to make the Evictor not > iterate > > >> > >> through > > >> > >> >> all > > >> > >> >> >> the > > >> > >> >> >> > > > elements in TimeEvictor. There will be a few changes > in > > >> the > > >> > >> >> existing > > >> > >> >> >> > > > behavior of TimeEvictor and DeltaEvictor (I have > > >> mentioned > > >> > >> this > > >> > >> >> in > > >> > >> >> >> the > > >> > >> >> >> > > > design doc) > > >> > >> >> >> > > > > > >> > >> >> >> > > > Also, is there any specific reason why the open and > > close > > >> > >> method > > >> > >> >> in > > >> > >> >> >> > > > WindowEvictor is made final? Since the EvictorContext > > >> will > > >> > be > > >> > >> in > > >> > >> >> the > > >> > >> >> >> > > > EvictingWindowOperator, I need to override the open > and > > >> > close > > >> > >> in > > >> > >> >> >> > > > EvitingWindowOperator to make the reference of > > >> > EvictorContext > > >> > >> >> null. > > >> > >> >> >> > > > > > >> > >> >> >> > > > Thanks and Regards, > > >> > >> >> >> > > > Vishnu Viswanath, > > >> > >> >> >> > > > > > >> > >> >> >> > > > On Fri, Jul 8, 2016 at 7:40 PM, Vishnu Viswanath < > > >> > >> >> >> > > > vishnu.viswanat...@gmail.com> wrote: > > >> > >> >> >> > > > > > >> > >> >> >> > > > My thought process when asking if we can use state > > >> backend > > >> > in > > >> > >> >> window > > >> > >> >> >> > > > > function was : can we add the elements to be > evicted > > >> into > > >> > >> some > > >> > >> >> >> state > > >> > >> >> >> > > and > > >> > >> >> >> > > > > allow the evictAfter to read it from some context > and > > >> > >> remove it > > >> > >> >> >> from > > >> > >> >> >> > > the > > >> > >> >> >> > > > > window? > > >> > >> >> >> > > > > > > >> > >> >> >> > > > > > > >> > >> >> >> > > > > On Fri, Jul 8, 2016 at 7:30 PM, Vishnu Viswanath < > > >> > >> >> >> > > > > vishnu.viswanat...@gmail.com> wrote: > > >> > >> >> >> > > > > > > >> > >> >> >> > > > >> Hi Aljoscha, > > >> > >> >> >> > > > >> > > >> > >> >> >> > > > >> Thanks for the explanation, and sorry for late > reply > > >> was > > >> > >> busy > > >> > >> >> >> with > > >> > >> >> >> > > work. > > >> > >> >> >> > > > >> > > >> > >> >> >> > > > >> I did think about this scenario, in fact in my > > >> previous > > >> > >> mail I > > >> > >> >> >> > thought > > >> > >> >> >> > > > of > > >> > >> >> >> > > > >> posting this question, then I understood that this > > >> > problem > > >> > >> >> will > > >> > >> >> >> be > > >> > >> >> >> > > > >> there which ever method we choose(Trigger looking > > for > > >> > >> pattern > > >> > >> >> or > > >> > >> >> >> > > Window > > >> > >> >> >> > > > >> looking for pattern). > > >> > >> >> >> > > > >> > > >> > >> >> >> > > > >> I do have a pretty good watermark but my concern > is > > >> that > > >> > it > > >> > >> >> >> changes > > >> > >> >> >> > > > based > > >> > >> >> >> > > > >> on the key of these messages(I don't know if it is > > >> > >> possible, > > >> > >> >> >> haven't > > >> > >> >> >> > > > >> started coding that yet. May be you could tell > me). > > >> Even > > >> > if > > >> > >> >> it is > > >> > >> >> >> > yes > > >> > >> >> >> > > > some > > >> > >> >> >> > > > >> of these watermarks will be long(in days), which I > > >> don't > > >> > >> want > > >> > >> >> the > > >> > >> >> >> > > > trigger > > >> > >> >> >> > > > >> to wait that long. > > >> > >> >> >> > > > >> > > >> > >> >> >> > > > >> It looks like it is not easy to have an evictAfter > > >> based > > >> > on > > >> > >> >> >> window > > >> > >> >> >> > > > >> function(without introducing coupling), but can > the > > >> > current > > >> > >> >> >> window > > >> > >> >> >> > > apply > > >> > >> >> >> > > > >> function be modified to allow it to change the > > >> elements > > >> > in > > >> > >> it > > >> > >> >> - > > >> > >> >> >> may > > >> > >> >> >> > be > > >> > >> >> >> > > > >> using some state backend(I don't know how excatly > > the > > >> > >> >> internals > > >> > >> >> >> of > > >> > >> >> >> > > these > > >> > >> >> >> > > > >> work, so this might be a wrong question) > > >> > >> >> >> > > > >> > > >> > >> >> >> > > > >> Thanks and Regards, > > >> > >> >> >> > > > >> Vishnu Viswanath, > > >> > >> >> >> > > > >> > > >> > >> >> >> > > > >> On Fri, Jul 8, 2016 at 10:20 AM, Aljoscha Krettek > < > > >> > >> >> >> > > aljos...@apache.org> > > >> > >> >> >> > > > >> wrote: > > >> > >> >> >> > > > >> > > >> > >> >> >> > > > >>> Hi Vishnu, > > >> > >> >> >> > > > >>> how long would these patterns be? The Trigger > would > > >> not > > >> > >> have > > >> > >> >> to > > >> > >> >> >> > sort > > >> > >> >> >> > > > the > > >> > >> >> >> > > > >>> elements for every new element but just insert > the > > >> new > > >> > >> >> element > > >> > >> >> >> into > > >> > >> >> >> > > an > > >> > >> >> >> > > > >>> internal data structure. Only when it sees that > the > > >> > >> >> watermark is > > >> > >> >> >> > > past a > > >> > >> >> >> > > > >>> certain point would it check whether the pattern > > >> matches > > >> > >> and > > >> > >> >> >> > actually > > >> > >> >> >> > > > >>> Trigger. > > >> > >> >> >> > > > >>> > > >> > >> >> >> > > > >>> A general note regarding order and event time: I > > >> think > > >> > >> >> relying > > >> > >> >> >> on > > >> > >> >> >> > > this > > >> > >> >> >> > > > >>> for > > >> > >> >> >> > > > >>> computation is very tricky unless the watermark > is > > >> 100 % > > >> > >> >> >> correct or > > >> > >> >> >> > > you > > >> > >> >> >> > > > >>> completely discard elements that arrive after the > > >> > >> watermark, > > >> > >> >> >> i.e. > > >> > >> >> >> > > > >>> elements > > >> > >> >> >> > > > >>> that would break the promise of the watermark > that > > no > > >> > >> >> elements > > >> > >> >> >> with > > >> > >> >> >> > > an > > >> > >> >> >> > > > >>> earlier timestamp will ever arrive. The reason > for > > >> this > > >> > is > > >> > >> >> that > > >> > >> >> >> > there > > >> > >> >> >> > > > >>> could > > >> > >> >> >> > > > >>> always enter new elements that end up between > > already > > >> > seen > > >> > >> >> >> > elements. > > >> > >> >> >> > > > For > > >> > >> >> >> > > > >>> example, let's say we have this sequence of > > elements > > >> > when > > >> > >> the > > >> > >> >> >> > trigger > > >> > >> >> >> > > > >>> fires: > > >> > >> >> >> > > > >>> > > >> > >> >> >> > > > >>> a-b-a > > >> > >> >> >> > > > >>> > > >> > >> >> >> > > > >>> This is the sequence that you are looking for and > > you > > >> > emit > > >> > >> >> some > > >> > >> >> >> > > result > > >> > >> >> >> > > > >>> from > > >> > >> >> >> > > > >>> the WindowFunction. Now, new elements arrive that > > >> fall > > >> > in > > >> > >> >> >> between > > >> > >> >> >> > the > > >> > >> >> >> > > > >>> elements we already have: > > >> > >> >> >> > > > >>> > > >> > >> >> >> > > > >>> a-d-e-b-f-g-a > > >> > >> >> >> > > > >>> > > >> > >> >> >> > > > >>> This is an updated, sorted view of the actual > > >> event-time > > >> > >> >> stream > > >> > >> >> >> and > > >> > >> >> >> > > we > > >> > >> >> >> > > > >>> didn't realize that the stream actually looks > like > > >> this > > >> > >> >> before. > > >> > >> >> >> > Does > > >> > >> >> >> > > > this > > >> > >> >> >> > > > >>> still match the original pattern or should we now > > >> > consider > > >> > >> >> this > > >> > >> >> >> as > > >> > >> >> >> > > > >>> non-matching? If no, then the earlier successful > > >> match > > >> > for > > >> > >> >> a-b-a > > >> > >> >> >> > was > > >> > >> >> >> > > > >>> wrong > > >> > >> >> >> > > > >>> and we should never have processed it but we > didn't > > >> know > > >> > >> at > > >> > >> >> the > > >> > >> >> >> > time. > > >> > >> >> >> > > > If > > >> > >> >> >> > > > >>> yes, then pattern matching like this can be done > in > > >> the > > >> > >> >> Trigger > > >> > >> >> >> by > > >> > >> >> >> > > > having > > >> > >> >> >> > > > >>> something like pattern slots: You don't have to > > store > > >> > all > > >> > >> >> >> elements > > >> > >> >> >> > in > > >> > >> >> >> > > > the > > >> > >> >> >> > > > >>> Trigger, you just need to store possible > candidates > > >> that > > >> > >> >> could > > >> > >> >> >> > match > > >> > >> >> >> > > > the > > >> > >> >> >> > > > >>> pattern and ignore the other (in-between) > elements. > > >> > >> >> >> > > > >>> > > >> > >> >> >> > > > >>> Cheers, > > >> > >> >> >> > > > >>> Aljoscha > > >> > >> >> >> > > > >>> > > >> > >> >> >> > > > >>> On Fri, 8 Jul 2016 at 14:10 Vishnu Viswanath < > > >> > >> >> >> > > > >>> vishnu.viswanat...@gmail.com> > > >> > >> >> >> > > > >>> wrote: > > >> > >> >> >> > > > >>> > > >> > >> >> >> > > > >>> > Hi Aljoscha, > > >> > >> >> >> > > > >>> > > > >> > >> >> >> > > > >>> > That is a good idea, trying to tie it back to > the > > >> use > > >> > >> case, > > >> > >> >> >> > > > >>> > e.g., suppose trigger is looking for a pattern, > > >> a-b-a > > >> > >> and > > >> > >> >> >> when it > > >> > >> >> >> > > > sees > > >> > >> >> >> > > > >>> such > > >> > >> >> >> > > > >>> > a pattern, it will trigger the window and it > > knows > > >> > that > > >> > >> now > > >> > >> >> >> the > > >> > >> >> >> > > > >>> Evictor is > > >> > >> >> >> > > > >>> > going to evict the element b, and trigger > updates > > >> its > > >> > >> >> state as > > >> > >> >> >> > a-a > > >> > >> >> >> > > > >>> (even > > >> > >> >> >> > > > >>> > before the window & evictor completes) and will > > be > > >> > >> looking > > >> > >> >> for > > >> > >> >> >> > the > > >> > >> >> >> > > > >>> rest of > > >> > >> >> >> > > > >>> > the pattern i.e., b-a. But I can think of 1 > > problem > > >> > >> here, > > >> > >> >> >> > > > >>> > > > >> > >> >> >> > > > >>> > - the events can arrive out of order, i.e., > > the > > >> > >> trigger > > >> > >> >> >> might > > >> > >> >> >> > be > > >> > >> >> >> > > > >>> seeing > > >> > >> >> >> > > > >>> > a pattern a-a-b but actual event time is > a-b-a > > >> then > > >> > >> >> trigger > > >> > >> >> >> > will > > >> > >> >> >> > > > >>> have to > > >> > >> >> >> > > > >>> > sort the elements in the window everytime it > > >> sees > > >> > an > > >> > >> >> >> element. > > >> > >> >> >> > (I > > >> > >> >> >> > > > was > > >> > >> >> >> > > > >>> > planning to do this sorting in the window, > > which > > >> > >> will be > > >> > >> >> >> less > > >> > >> >> >> > > > often > > >> > >> >> >> > > > >>> - > > >> > >> >> >> > > > >>> > only > > >> > >> >> >> > > > >>> > when the trigger fires) > > >> > >> >> >> > > > >>> > > > >> > >> >> >> > > > >>> > Thanks and Regards, > > >> > >> >> >> > > > >>> > Vishnu Viswanath, > > >> > >> >> >> > > > >>> > > > >> > >> >> >> > > > >>> > On Fri, Jul 8, 2016 at 6:04 AM, Aljoscha > Krettek > > < > > >> > >> >> >> > > > aljos...@apache.org> > > >> > >> >> >> > > > >>> > wrote: > > >> > >> >> >> > > > >>> > > > >> > >> >> >> > > > >>> > Hi, > > >> > >> >> >> > > > >>> > > come to think of it, the right place to put > > such > > >> > >> checks > > >> > >> >> is > > >> > >> >> >> > > actually > > >> > >> >> >> > > > >>> the > > >> > >> >> >> > > > >>> > > Trigger. It would have to be a custom trigger > > >> that > > >> > >> >> observes > > >> > >> >> >> > time > > >> > >> >> >> > > > but > > >> > >> >> >> > > > >>> also > > >> > >> >> >> > > > >>> > > keeps some internal state machine to decide > > when > > >> it > > >> > >> has > > >> > >> >> >> > observed > > >> > >> >> >> > > > the > > >> > >> >> >> > > > >>> > right > > >> > >> >> >> > > > >>> > > pattern in the window. Then the window > function > > >> > would > > >> > >> >> just > > >> > >> >> >> have > > >> > >> >> >> > > to > > >> > >> >> >> > > > >>> do the > > >> > >> >> >> > > > >>> > > processing and you have good separation of > > >> concerns. > > >> > >> Does > > >> > >> >> >> that > > >> > >> >> >> > > make > > >> > >> >> >> > > > >>> > sense? > > >> > >> >> >> > > > >>> > > > > >> > >> >> >> > > > >>> > > I'm ignoring time and sorting by time for now > > >> > because > > >> > >> we > > >> > >> >> >> > probably > > >> > >> >> >> > > > >>> need > > >> > >> >> >> > > > >>> > > another design document for that. To me it > > seems > > >> > like > > >> > >> a > > >> > >> >> >> bigger > > >> > >> >> >> > > > thing. > > >> > >> >> >> > > > >>> > > > > >> > >> >> >> > > > >>> > > Cheers, > > >> > >> >> >> > > > >>> > > Aljoscha > > >> > >> >> >> > > > >>> > > > > >> > >> >> >> > > > >>> > > On Thu, 7 Jul 2016 at 23:56 Vishnu Viswanath > < > > >> > >> >> >> > > > >>> > vishnu.viswanat...@gmail.com > > >> > >> >> >> > > > >>> > > > > > >> > >> >> >> > > > >>> > > wrote: > > >> > >> >> >> > > > >>> > > > > >> > >> >> >> > > > >>> > > > Hi, > > >> > >> >> >> > > > >>> > > > > > >> > >> >> >> > > > >>> > > > Regarding the evictAfter function, that > > evicts > > >> > >> based on > > >> > >> >> >> some > > >> > >> >> >> > > > >>> decision > > >> > >> >> >> > > > >>> > > made > > >> > >> >> >> > > > >>> > > > by the window function: I think it will be > > >> nice > > >> > if > > >> > >> we > > >> > >> >> can > > >> > >> >> >> > come > > >> > >> >> >> > > > up > > >> > >> >> >> > > > >>> with > > >> > >> >> >> > > > >>> > > > something that is LESS coupled, because I > can > > >> > think > > >> > >> of > > >> > >> >> >> > several > > >> > >> >> >> > > > use > > >> > >> >> >> > > > >>> > cases > > >> > >> >> >> > > > >>> > > > that depend on it. > > >> > >> >> >> > > > >>> > > > > > >> > >> >> >> > > > >>> > > > Especially in the case where there are late > > >> > arriving > > >> > >> >> >> > messages. > > >> > >> >> >> > > > Only > > >> > >> >> >> > > > >>> > after > > >> > >> >> >> > > > >>> > > > the window function is applied we could > tell > > >> what > > >> > >> to do > > >> > >> >> >> with > > >> > >> >> >> > > the > > >> > >> >> >> > > > >>> > elements > > >> > >> >> >> > > > >>> > > > in the window. You could apply your > business > > >> logic > > >> > >> >> there > > >> > >> >> >> to > > >> > >> >> >> > > > >>> determine > > >> > >> >> >> > > > >>> > if > > >> > >> >> >> > > > >>> > > > the window funciton was able to do what it > is > > >> > >> supposed > > >> > >> >> to > > >> > >> >> >> do, > > >> > >> >> >> > > if > > >> > >> >> >> > > > >>> yes > > >> > >> >> >> > > > >>> > > evict > > >> > >> >> >> > > > >>> > > > those elements, else(since the elements you > > are > > >> > >> looking > > >> > >> >> >> for > > >> > >> >> >> > > > haven't > > >> > >> >> >> > > > >>> > > arrived > > >> > >> >> >> > > > >>> > > > yet) wait and try again when the trigger > gets > > >> > fired > > >> > >> >> next > > >> > >> >> >> > time. > > >> > >> >> >> > > > >>> > > > > > >> > >> >> >> > > > >>> > > > Thanks and Regards, > > >> > >> >> >> > > > >>> > > > Vishnu Viswanath, > > >> > >> >> >> > > > >>> > > > > > >> > >> >> >> > > > >>> > > > > > >> > >> >> >> > > > >>> > > > On Thu, Jul 7, 2016 at 9:19 AM, Radu > Tudoran > > < > > >> > >> >> >> > > > >>> radu.tudo...@huawei.com> > > >> > >> >> >> > > > >>> > > > wrote: > > >> > >> >> >> > > > >>> > > > > > >> > >> >> >> > > > >>> > > > > Hi, > > >> > >> >> >> > > > >>> > > > > > > >> > >> >> >> > > > >>> > > > > @Aljoscha - I can understand the reason > why > > >> you > > >> > >> are > > >> > >> >> >> > hesitant > > >> > >> >> >> > > to > > >> > >> >> >> > > > >>> > > introduce > > >> > >> >> >> > > > >>> > > > > "slower" windows such as the ones that > > would > > >> > >> maintain > > >> > >> >> >> > sorted > > >> > >> >> >> > > > >>> items or > > >> > >> >> >> > > > >>> > > > > windows with bindings between the > different > > >> > >> entities > > >> > >> >> >> > > (evictor, > > >> > >> >> >> > > > >>> > trigger, > > >> > >> >> >> > > > >>> > > > > window, apply function). However, I think > > >> it's > > >> > >> >> possible > > >> > >> >> >> > just > > >> > >> >> >> > > to > > >> > >> >> >> > > > >>> > create > > >> > >> >> >> > > > >>> > > > more > > >> > >> >> >> > > > >>> > > > > types of windows. The existing ones > > >> > (timewindows, > > >> > >> >> global > > >> > >> >> >> > > > windows > > >> > >> >> >> > > > >>> ...) > > >> > >> >> >> > > > >>> > > can > > >> > >> >> >> > > > >>> > > > > remain, and just add some more flavors of > > >> > windows > > >> > >> >> were > > >> > >> >> >> more > > >> > >> >> >> > > > >>> features > > >> > >> >> >> > > > >>> > > are > > >> > >> >> >> > > > >>> > > > > enabled or more functionality (e.g., > access > > >> to > > >> > the > > >> > >> >> each > > >> > >> >> >> > > element > > >> > >> >> >> > > > >>> in > > >> > >> >> >> > > > >>> > the > > >> > >> >> >> > > > >>> > > > > evictor ; possibility to delete or mark > for > > >> > >> eviction > > >> > >> >> >> > elements > > >> > >> >> >> > > > in > > >> > >> >> >> > > > >>> the > > >> > >> >> >> > > > >>> > > > > function...) > > >> > >> >> >> > > > >>> > > > > > > >> > >> >> >> > > > >>> > > > > Regarding the specific case of sorted > > >> windows, I > > >> > >> >> think > > >> > >> >> >> the > > >> > >> >> >> > N > > >> > >> >> >> > > > lon > > >> > >> >> >> > > > >>> N > > >> > >> >> >> > > > >>> > > > > complexity to sort (the worst case) is > very > > >> > >> >> unlikely. In > > >> > >> >> >> > fact > > >> > >> >> >> > > > you > > >> > >> >> >> > > > >>> > have > > >> > >> >> >> > > > >>> > > > > almost sorted items/arrays. Moreover, if > > you > > >> > >> consider > > >> > >> >> >> that > > >> > >> >> >> > in > > >> > >> >> >> > > > >>> > > iteration X > > >> > >> >> >> > > > >>> > > > > all elements were sorted, then in > iteration > > >> X+1 > > >> > >> you > > >> > >> >> will > > >> > >> >> >> > need > > >> > >> >> >> > > > to > > >> > >> >> >> > > > >>> sort > > >> > >> >> >> > > > >>> > > > just > > >> > >> >> >> > > > >>> > > > > the newly arrived elements (M). I would > > >> expect > > >> > >> that > > >> > >> >> this > > >> > >> >> >> > > > number M > > >> > >> >> >> > > > >>> > might > > >> > >> >> >> > > > >>> > > > be > > >> > >> >> >> > > > >>> > > > > significant smaller then N (elements that > > >> > exists). > > >> > >> >> Then > > >> > >> >> >> > using > > >> > >> >> >> > > > an > > >> > >> >> >> > > > >>> > > > insertion > > >> > >> >> >> > > > >>> > > > > sort for these new elements you would > have > > >> M * > > >> > N > > >> > >> >> >> > complexity > > >> > >> >> >> > > > and > > >> > >> >> >> > > > >>> if > > >> > >> >> >> > > > >>> > > M<< N > > >> > >> >> >> > > > >>> > > > > then the complexity is O(N). > Alternatively > > >> you > > >> > can > > >> > >> >> use a > > >> > >> >> >> > > binary > > >> > >> >> >> > > > >>> > search > > >> > >> >> >> > > > >>> > > > for > > >> > >> >> >> > > > >>> > > > > insertion and then you further reduce the > > >> > >> complexity > > >> > >> >> to > > >> > >> >> >> > > > O(logN). > > >> > >> >> >> > > > >>> > > > > If M is proportional to N then you can > > sort M > > >> > and > > >> > >> use > > >> > >> >> >> merge > > >> > >> >> >> > > > sort > > >> > >> >> >> > > > >>> for > > >> > >> >> >> > > > >>> > > > > combining. > > >> > >> >> >> > > > >>> > > > > > > >> > >> >> >> > > > >>> > > > > > > >> > >> >> >> > > > >>> > > > > Dr. Radu Tudoran > > >> > >> >> >> > > > >>> > > > > Research Engineer - Big Data Expert > > >> > >> >> >> > > > >>> > > > > IT R&D Division > > >> > >> >> >> > > > >>> > > > > > > >> > >> >> >> > > > >>> > > > > > > >> > >> >> >> > > > >>> > > > > HUAWEI TECHNOLOGIES Duesseldorf GmbH > > >> > >> >> >> > > > >>> > > > > European Research Center > > >> > >> >> >> > > > >>> > > > > Riesstrasse 25, 80992 München > > >> > >> >> >> > > > >>> > > > > > > >> > >> >> >> > > > >>> > > > > E-mail: radu.tudo...@huawei.com > > >> > >> >> >> > > > >>> > > > > Mobile: +49 15209084330 > > >> > >> >> >> > > > >>> > > > > Telephone: +49 891588344173 > > >> > >> >> >> > > > >>> > > > > > > >> > >> >> >> > > > >>> > > > > HUAWEI TECHNOLOGIES Duesseldorf GmbH > > >> > >> >> >> > > > >>> > > > > Hansaallee 205, 40549 Düsseldorf, > Germany, > > >> > >> >> >> www.huawei.com > > >> > >> >> >> > > > >>> > > > > Registered Office: Düsseldorf, Register > > Court > > >> > >> >> >> Düsseldorf, > > >> > >> >> >> > HRB > > >> > >> >> >> > > > >>> 56063, > > >> > >> >> >> > > > >>> > > > > Managing Director: Bo PENG, Wanzhou MENG, > > >> Lifang > > >> > >> CHEN > > >> > >> >> >> > > > >>> > > > > Sitz der Gesellschaft: Düsseldorf, > > >> Amtsgericht > > >> > >> >> >> Düsseldorf, > > >> > >> >> >> > > HRB > > >> > >> >> >> > > > >>> 56063, > > >> > >> >> >> > > > >>> > > > > Geschäftsführer: Bo PENG, Wanzhou MENG, > > >> Lifang > > >> > >> CHEN > > >> > >> >> >> > > > >>> > > > > This e-mail and its attachments contain > > >> > >> confidential > > >> > >> >> >> > > > information > > >> > >> >> >> > > > >>> from > > >> > >> >> >> > > > >>> > > > > HUAWEI, which is intended only for the > > >> person or > > >> > >> >> entity > > >> > >> >> >> > whose > > >> > >> >> >> > > > >>> address > > >> > >> >> >> > > > >>> > > is > > >> > >> >> >> > > > >>> > > > > listed above. Any use of the information > > >> > contained > > >> > >> >> >> herein > > >> > >> >> >> > in > > >> > >> >> >> > > > any > > >> > >> >> >> > > > >>> way > > >> > >> >> >> > > > >>> > > > > (including, but not limited to, total or > > >> partial > > >> > >> >> >> > disclosure, > > >> > >> >> >> > > > >>> > > > reproduction, > > >> > >> >> >> > > > >>> > > > > or dissemination) by persons other than > the > > >> > >> intended > > >> > >> >> >> > > > >>> recipient(s) is > > >> > >> >> >> > > > >>> > > > > prohibited. If you receive this e-mail in > > >> error, > > >> > >> >> please > > >> > >> >> >> > > notify > > >> > >> >> >> > > > >>> the > > >> > >> >> >> > > > >>> > > sender > > >> > >> >> >> > > > >>> > > > > by phone or email immediately and delete > > it! > > >> > >> >> >> > > > >>> > > > > > > >> > >> >> >> > > > >>> > > > > > > >> > >> >> >> > > > >>> > > > > -----Original Message----- > > >> > >> >> >> > > > >>> > > > > From: 吕文龙(吕文龙) [mailto: > > >> > >> wenlong....@alibaba-inc.com] > > >> > >> >> >> > > > >>> > > > > Sent: Thursday, July 07, 2016 11:59 AM > > >> > >> >> >> > > > >>> > > > > To: dev@flink.apache.org > > >> > >> >> >> > > > >>> > > > > Subject: 答复: [DISCUSS] Enhance Window > > >> Evictor in > > >> > >> >> Flink > > >> > >> >> >> > > > >>> > > > > > > >> > >> >> >> > > > >>> > > > > HI, > > >> > >> >> >> > > > >>> > > > > I think it is necessary to support sorted > > >> > window, > > >> > >> >> which > > >> > >> >> >> can > > >> > >> >> >> > > > avoid > > >> > >> >> >> > > > >>> > > > scanning > > >> > >> >> >> > > > >>> > > > > all the elements of window while trying > to > > >> > >> evicting > > >> > >> >> >> > element, > > >> > >> >> >> > > > >>> which > > >> > >> >> >> > > > >>> > may > > >> > >> >> >> > > > >>> > > > cost > > >> > >> >> >> > > > >>> > > > > many IO operations, such as querying DBs > to > > >> get > > >> > >> >> elements > > >> > >> >> >> > from > > >> > >> >> >> > > > >>> state. > > >> > >> >> >> > > > >>> > > > > What's more, when an window aggregation > > >> function > > >> > >> is > > >> > >> >> >> > > invertible, > > >> > >> >> >> > > > >>> such > > >> > >> >> >> > > > >>> > as > > >> > >> >> >> > > > >>> > > > > sum, which can be updated by adding or > > >> removing > > >> > a > > >> > >> >> single > > >> > >> >> >> > > > record, > > >> > >> >> >> > > > >>> > window > > >> > >> >> >> > > > >>> > > > > results can be incrementally calculated. > In > > >> this > > >> > >> >> kind of > > >> > >> >> >> > > case, > > >> > >> >> >> > > > >>> we can > > >> > >> >> >> > > > >>> > > > > dramatically improve the performance of > > >> window > > >> > >> >> >> aggregation, > > >> > >> >> >> > > if > > >> > >> >> >> > > > >>> > evictor > > >> > >> >> >> > > > >>> > > > can > > >> > >> >> >> > > > >>> > > > > trigger update of window aggregation > state > > by > > >> > some > > >> > >> >> >> > mechanism. > > >> > >> >> >> > > > >>> > > > > > > >> > >> >> >> > > > >>> > > > > Best Wishes! > > >> > >> >> >> > > > >>> > > > > --- > > >> > >> >> >> > > > >>> > > > > wenlong.lwl > > >> > >> >> >> > > > >>> > > > > > > >> > >> >> >> > > > >>> > > > > -----邮件原件----- > > >> > >> >> >> > > > >>> > > > > 发件人: Aljoscha Krettek [mailto: > > >> > aljos...@apache.org > > >> > >> ] > > >> > >> >> >> > > > >>> > > > > 发送时间: 2016年7月7日 17:32 > > >> > >> >> >> > > > >>> > > > > 收件人: dev@flink.apache.org > > >> > >> >> >> > > > >>> > > > > 主题: Re: [DISCUSS] Enhance Window Evictor > in > > >> > Flink > > >> > >> >> >> > > > >>> > > > > > > >> > >> >> >> > > > >>> > > > > Hi, > > >> > >> >> >> > > > >>> > > > > regarding "sorting the window by event > > >> time": I > > >> > >> also > > >> > >> >> >> > > considered > > >> > >> >> >> > > > >>> this > > >> > >> >> >> > > > >>> > > but > > >> > >> >> >> > > > >>> > > > > in the end I don't think it's necessary. > > >> Sorting > > >> > >> is > > >> > >> >> >> rather > > >> > >> >> >> > > > >>> expensive > > >> > >> >> >> > > > >>> > > and > > >> > >> >> >> > > > >>> > > > > making decisions based on the order of > > >> elements > > >> > >> can > > >> > >> >> be > > >> > >> >> >> > > tricky. > > >> > >> >> >> > > > An > > >> > >> >> >> > > > >>> > > extreme > > >> > >> >> >> > > > >>> > > > > example of why this can be problematic is > > the > > >> > case > > >> > >> >> where > > >> > >> >> >> > all > > >> > >> >> >> > > > >>> elements > > >> > >> >> >> > > > >>> > > in > > >> > >> >> >> > > > >>> > > > > the window have the same timestamp. Now, > if > > >> you > > >> > >> >> decide > > >> > >> >> >> to > > >> > >> >> >> > > evict > > >> > >> >> >> > > > >>> the > > >> > >> >> >> > > > >>> > > > first 5 > > >> > >> >> >> > > > >>> > > > > elements based on timestamp order you > > >> basically > > >> > >> >> >> arbitrarily > > >> > >> >> >> > > > >>> evict 5 > > >> > >> >> >> > > > >>> > > > > elements. I think the better solution for > > >> doing > > >> > >> >> >> time-based > > >> > >> >> >> > > > >>> eviction > > >> > >> >> >> > > > >>> > is > > >> > >> >> >> > > > >>> > > to > > >> > >> >> >> > > > >>> > > > > do one pass over the elements to get an > > >> overview > > >> > >> of > > >> > >> >> the > > >> > >> >> >> > > > timestamp > > >> > >> >> >> > > > >>> > > > > distribution, then do a second pass and > > evict > > >> > >> >> elements > > >> > >> >> >> > based > > >> > >> >> >> > > on > > >> > >> >> >> > > > >>> what > > >> > >> >> >> > > > >>> > > was > > >> > >> >> >> > > > >>> > > > > learned in the first pass. This has > > >> complexity > > >> > 2*n > > >> > >> >> >> compared > > >> > >> >> >> > > to > > >> > >> >> >> > > > >>> the > > >> > >> >> >> > > > >>> > > n*log > > >> > >> >> >> > > > >>> > > > n > > >> > >> >> >> > > > >>> > > > > (plus the work of actually deciding what > to > > >> > >> evict) of > > >> > >> >> >> the > > >> > >> >> >> > > sort > > >> > >> >> >> > > > >>> based > > >> > >> >> >> > > > >>> > > > > strategy. > > >> > >> >> >> > > > >>> > > > > > > >> > >> >> >> > > > >>> > > > > I might be wrong, though, and there could > > be > > >> a > > >> > >> valid > > >> > >> >> >> > use-case > > >> > >> >> >> > > > not > > >> > >> >> >> > > > >>> > > covered > > >> > >> >> >> > > > >>> > > > > by the above idea. > > >> > >> >> >> > > > >>> > > > > > > >> > >> >> >> > > > >>> > > > > regarding Vishnu's other use case of > > evicting > > >> > >> based > > >> > >> >> on > > >> > >> >> >> some > > >> > >> >> >> > > > >>> decision > > >> > >> >> >> > > > >>> > in > > >> > >> >> >> > > > >>> > > > the > > >> > >> >> >> > > > >>> > > > > WindowFunction: could this be solved by > > doing > > >> > the > > >> > >> >> check > > >> > >> >> >> for > > >> > >> >> >> > > the > > >> > >> >> >> > > > >>> > pattern > > >> > >> >> >> > > > >>> > > > in > > >> > >> >> >> > > > >>> > > > > the evictor itself instead of in the > window > > >> > >> function? > > >> > >> >> >> I'm > > >> > >> >> >> > > very > > >> > >> >> >> > > > >>> > hesitant > > >> > >> >> >> > > > >>> > > > to > > >> > >> >> >> > > > >>> > > > > introduce a coupling between the > different > > >> > >> >> components of > > >> > >> >> >> > the > > >> > >> >> >> > > > >>> > windowing > > >> > >> >> >> > > > >>> > > > > system, i.e. assigner, trigger, evictor > and > > >> > window > > >> > >> >> >> > function. > > >> > >> >> >> > > > The > > >> > >> >> >> > > > >>> > reason > > >> > >> >> >> > > > >>> > > > is > > >> > >> >> >> > > > >>> > > > > that using an evictor has a huge > > performance > > >> > >> impact > > >> > >> >> >> since > > >> > >> >> >> > the > > >> > >> >> >> > > > >>> system > > >> > >> >> >> > > > >>> > > > always > > >> > >> >> >> > > > >>> > > > > has to keep all elements and cannot to > > >> > incremental > > >> > >> >> >> > > aggregation > > >> > >> >> >> > > > of > > >> > >> >> >> > > > >>> > > window > > >> > >> >> >> > > > >>> > > > > results and I therefore don't want to put > > >> > specific > > >> > >> >> >> features > > >> > >> >> >> > > > >>> regarding > > >> > >> >> >> > > > >>> > > > > eviction into the other components. > > >> > >> >> >> > > > >>> > > > > > > >> > >> >> >> > > > >>> > > > > Cheers, > > >> > >> >> >> > > > >>> > > > > Aljoscha > > >> > >> >> >> > > > >>> > > > > > > >> > >> >> >> > > > >>> > > > > On Thu, 7 Jul 2016 at 10:00 Radu Tudoran > < > > >> > >> >> >> > > > >>> radu.tudo...@huawei.com> > > >> > >> >> >> > > > >>> > > > wrote: > > >> > >> >> >> > > > >>> > > > > > > >> > >> >> >> > > > >>> > > > > > Hi, > > >> > >> >> >> > > > >>> > > > > > > > >> > >> >> >> > > > >>> > > > > > I think the situation Vishnu raised is > > >> > something > > >> > >> >> that > > >> > >> >> >> > > should > > >> > >> >> >> > > > be > > >> > >> >> >> > > > >>> > > > > accounted. > > >> > >> >> >> > > > >>> > > > > > It can happen indeed that you want to > > >> > condition > > >> > >> >> what > > >> > >> >> >> you > > >> > >> >> >> > > > evict > > >> > >> >> >> > > > >>> from > > >> > >> >> >> > > > >>> > > > > > the window based on the result of the > > >> function > > >> > >> to > > >> > >> >> be > > >> > >> >> >> > > applied. > > >> > >> >> >> > > > >>> > > > > > > > >> > >> >> >> > > > >>> > > > > > My 2 cents... > > >> > >> >> >> > > > >>> > > > > > I would suggest adding a list for the > > >> elements > > >> > >> of > > >> > >> >> the > > >> > >> >> >> > > stream > > >> > >> >> >> > > > >>> where > > >> > >> >> >> > > > >>> > > you > > >> > >> >> >> > > > >>> > > > > > can MARK them to be delete. > Alternatively > > >> the > > >> > >> >> iterator > > >> > >> >> >> > can > > >> > >> >> >> > > be > > >> > >> >> >> > > > >>> > > extended > > >> > >> >> >> > > > >>> > > > > > to have a function > > >> > >> Iterator.markForEviction(int); > > >> > >> >> >> These > > >> > >> >> >> > can > > >> > >> >> >> > > > be > > >> > >> >> >> > > > >>> made > > >> > >> >> >> > > > >>> > > > > > available also in the apply function. > > >> > Moreover, > > >> > >> we > > >> > >> >> can > > >> > >> >> >> > use > > >> > >> >> >> > > > >>> this to > > >> > >> >> >> > > > >>> > > > > > extend the functionality such that you > > add > > >> > MARKs > > >> > >> >> >> either > > >> > >> >> >> > for > > >> > >> >> >> > > > >>> > eviction > > >> > >> >> >> > > > >>> > > > > > after the function has finished > > triggering > > >> or > > >> > >> to be > > >> > >> >> >> > evicted > > >> > >> >> >> > > > in > > >> > >> >> >> > > > >>> the > > >> > >> >> >> > > > >>> > > next > > >> > >> >> >> > > > >>> > > > > iteration. > > >> > >> >> >> > > > >>> > > > > > > > >> > >> >> >> > > > >>> > > > > > > > >> > >> >> >> > > > >>> > > > > > Dr. Radu Tudoran > > >> > >> >> >> > > > >>> > > > > > Research Engineer - Big Data Expert > > >> > >> >> >> > > > >>> > > > > > IT R&D Division > > >> > >> >> >> > > > >>> > > > > > > > >> > >> >> >> > > > >>> > > > > > > > >> > >> >> >> > > > >>> > > > > > HUAWEI TECHNOLOGIES Duesseldorf GmbH > > >> > >> >> >> > > > >>> > > > > > European Research Center > > >> > >> >> >> > > > >>> > > > > > Riesstrasse 25, 80992 München > > >> > >> >> >> > > > >>> > > > > > > > >> > >> >> >> > > > >>> > > > > > E-mail: radu.tudo...@huawei.com > > >> > >> >> >> > > > >>> > > > > > Mobile: +49 15209084330 > > >> > >> >> >> > > > >>> > > > > > Telephone: +49 891588344173 > > >> > >> >> >> > > > >>> > > > > > > > >> > >> >> >> > > > >>> > > > > > HUAWEI TECHNOLOGIES Duesseldorf GmbH > > >> > >> >> >> > > > >>> > > > > > Hansaallee 205, 40549 Düsseldorf, > > Germany, > > >> > >> >> >> > www.huawei.com > > >> > >> >> >> > > > >>> > Registered > > >> > >> >> >> > > > >>> > > > > > Office: Düsseldorf, Register Court > > >> Düsseldorf, > > >> > >> HRB > > >> > >> >> >> 56063, > > >> > >> >> >> > > > >>> Managing > > >> > >> >> >> > > > >>> > > > > > Director: Bo PENG, Wanzhou MENG, Lifang > > >> CHEN > > >> > >> Sitz > > >> > >> >> der > > >> > >> >> >> > > > >>> Gesellschaft: > > >> > >> >> >> > > > >>> > > > > > Düsseldorf, Amtsgericht Düsseldorf, HRB > > >> 56063, > > >> > >> >> >> > > > >>> > > > > > Geschäftsführer: Bo PENG, Wanzhou MENG, > > >> Lifang > > >> > >> CHEN > > >> > >> >> >> This > > >> > >> >> >> > > > >>> e-mail and > > >> > >> >> >> > > > >>> > > > > > its attachments contain confidential > > >> > information > > >> > >> >> from > > >> > >> >> >> > > HUAWEI, > > >> > >> >> >> > > > >>> which > > >> > >> >> >> > > > >>> > > is > > >> > >> >> >> > > > >>> > > > > > intended only for the person or entity > > >> whose > > >> > >> >> address > > >> > >> >> >> is > > >> > >> >> >> > > > listed > > >> > >> >> >> > > > >>> > above. > > >> > >> >> >> > > > >>> > > > > > Any use of the information contained > > >> herein in > > >> > >> any > > >> > >> >> way > > >> > >> >> >> > > > >>> (including, > > >> > >> >> >> > > > >>> > > but > > >> > >> >> >> > > > >>> > > > > > not limited to, total or partial > > >> disclosure, > > >> > >> >> >> > reproduction, > > >> > >> >> >> > > or > > >> > >> >> >> > > > >>> > > > > > dissemination) by persons other than > the > > >> > >> intended > > >> > >> >> >> > > > recipient(s) > > >> > >> >> >> > > > >>> is > > >> > >> >> >> > > > >>> > > > > > prohibited. If you receive this e-mail > in > > >> > error, > > >> > >> >> >> please > > >> > >> >> >> > > > notify > > >> > >> >> >> > > > >>> the > > >> > >> >> >> > > > >>> > > > > > sender by phone or email immediately > and > > >> > delete > > >> > >> it! > > >> > >> >> >> > > > >>> > > > > > > > >> > >> >> >> > > > >>> > > > > > -----Original Message----- > > >> > >> >> >> > > > >>> > > > > > From: Vishnu Viswanath [mailto: > > >> > >> >> >> > > vishnu.viswanat...@gmail.com] > > >> > >> >> >> > > > >>> > > > > > Sent: Thursday, July 07, 2016 1:28 AM > > >> > >> >> >> > > > >>> > > > > > To: Dev > > >> > >> >> >> > > > >>> > > > > > Subject: Re: [DISCUSS] Enhance Window > > >> Evictor > > >> > in > > >> > >> >> Flink > > >> > >> >> >> > > > >>> > > > > > > > >> > >> >> >> > > > >>> > > > > > Thank you Maxim and Aljoscha. > > >> > >> >> >> > > > >>> > > > > > > > >> > >> >> >> > > > >>> > > > > > Yes the beforeEvict and afterEvict > should > > >> able > > >> > >> >> address > > >> > >> >> >> > > point > > >> > >> >> >> > > > 3. > > >> > >> >> >> > > > >>> > > > > > > > >> > >> >> >> > > > >>> > > > > > I have one more use case in my mind > > (which > > >> I > > >> > >> might > > >> > >> >> >> have > > >> > >> >> >> > to > > >> > >> >> >> > > do > > >> > >> >> >> > > > >>> in > > >> > >> >> >> > > > >>> > the > > >> > >> >> >> > > > >>> > > > > > later stages of POC). > > >> > >> >> >> > > > >>> > > > > > What if the `evictAfter` should behave > > >> > >> differently > > >> > >> >> >> based > > >> > >> >> >> > on > > >> > >> >> >> > > > the > > >> > >> >> >> > > > >>> > > window > > >> > >> >> >> > > > >>> > > > > > function. > > >> > >> >> >> > > > >>> > > > > > > > >> > >> >> >> > > > >>> > > > > > For example. > > >> > >> >> >> > > > >>> > > > > > I have a window that got triggered and > my > > >> > evict > > >> > >> >> >> function > > >> > >> >> >> > is > > >> > >> >> >> > > > >>> being > > >> > >> >> >> > > > >>> > > > > > called after the apply function. In > such > > >> > cases I > > >> > >> >> >> should > > >> > >> >> >> > be > > >> > >> >> >> > > > >>> able to > > >> > >> >> >> > > > >>> > > > > > decide on what I should evict based on > > the > > >> > >> window > > >> > >> >> >> > function. > > >> > >> >> >> > > > >>> > > > > > e.g., > > >> > >> >> >> > > > >>> > > > > > let the window have elements of type > > `case > > >> > class > > >> > >> >> >> Item(id: > > >> > >> >> >> > > > >>> String, > > >> > >> >> >> > > > >>> > > type: > > >> > >> >> >> > > > >>> > > > > > String)` and let the types be `type1` > > and > > >> > >> `type2`. > > >> > >> >> >> > > > >>> > > > > > If window function is able to find a > > >> sequence > > >> > : > > >> > >> >> `type1 > > >> > >> >> >> > > type2 > > >> > >> >> >> > > > >>> > type1`, > > >> > >> >> >> > > > >>> > > > > > then evict all elements of the type > > type2. > > >> > >> >> >> > > > >>> > > > > > or if the window function is able to > > find a > > >> > >> >> sequence > > >> > >> >> >> > `type2 > > >> > >> >> >> > > > >>> type2 > > >> > >> >> >> > > > >>> > > > > > type1`, then evict all elements of type > > >> type1 > > >> > >> else > > >> > >> >> >> don't > > >> > >> >> >> > > > evict > > >> > >> >> >> > > > >>> any > > >> > >> >> >> > > > >>> > > > > elements. > > >> > >> >> >> > > > >>> > > > > > > > >> > >> >> >> > > > >>> > > > > > Is this possible? or at least let the > > >> window > > >> > >> >> function > > >> > >> >> >> > > choose > > >> > >> >> >> > > > >>> > between > > >> > >> >> >> > > > >>> > > > > > two Evictor functions -(one for success > > >> case > > >> > and > > >> > >> >> one > > >
