Hi Guozhang, I have clarified the KIP a bit to account for Becket's suggestion on ClientTimeoutException. About adding an extra config, you were right about my intentions. I am just wondering if the config should be included, since Ismael seems to favor an extra configuration,
Thanks, Richard On Sun, Apr 1, 2018 at 5:35 PM, Guozhang Wang <wangg...@gmail.com> wrote: > Hi Richard, > > Regarding the streams side changes, we plan to incorporate with the new > APIs once the KIP is done, which is only internal code changes and hence do > not need to include in the KIP. > > Could you update the KIP because it has been quite obsoleted from the > discussed topics, and I'm a bit loosing track on what is your final > proposal right now. For example, I'm not completely following your > "compromise > of sorts": are you suggesting that we still add overloading functions and > add a config that will be applied to all overload functions without the > timeout, while for other overloaded functions with the timeout value the > config will be ignored? > > > Guozhang > > On Fri, Mar 30, 2018 at 8:36 PM, Richard Yu <yohan.richard...@gmail.com> > wrote: > > > On a side note, I have noticed that the several other methods in classes > > such as StoreChangeLogReader in Streams calls position() which causes > tests > > to hang. It might be out of the scope of the KIP, but should I also > change > > the methods which use position() as a callback to at the very least > prevent > > the tests from hanging? This issue might be out of the KIP, but I prefer > it > > if we could at least make my PR pass the Jenkins Q&A. > > > > Thanks > > > > On Fri, Mar 30, 2018 at 8:24 PM, Richard Yu <yohan.richard...@gmail.com> > > wrote: > > > > > Thanks for the review Becket. > > > > > > About the methods beginningOffsets(), endOffsets(), ...: > > > I took a look through the code of KafkaConsumer, but after looking > > through > > > the offsetsByTimes() method > > > and its callbacks in Fetcher, I think these methods already block for a > > > set period of time. I know that there > > > is a chance that the offsets methods in KafkaConsumer might be like > poll > > > (that is one section of the method > > > honors the timeout while another -- updateFetchPositions -- does not). > > > However, I don't think that this is the > > > case with offsetsByTimes since the callbacks that I checked does not > seem > > > to hang. > > > > > > The clarity of the exception message is a problem. I thought your > > > suggestion there was reasonable. I included > > > it in the KIP. > > > > > > And on another note, I have noticed that several people has voiced the > > > opinion that adding a config might > > > be advisable in relation to adding an extra parameter. I think that we > > can > > > have a compromise of sorts: some > > > methods in KafkaConsumer are relatively similar -- for example, > > position() > > > and committed() both call > > > updateFetchPositions(). I think that we could use the same config for > > > these method as a default timeout if > > > the user does not provide one. On the other hand, if they wish to > specify > > > a longer or shorter blocking time, > > > they have the option of changing the timeout. (I included the config as > > an > > > alternative in the KIP) WDYT? > > > > > > Thanks, > > > Richard > > > > > > > > > On Fri, Mar 30, 2018 at 1:26 AM, Becket Qin <becket....@gmail.com> > > wrote: > > > > > >> Glad to see the KIP, Richard. This has been a really long pending > issue. > > >> > > >> The original arguments from Jay for using config, such as > max.block.ms, > > >> instead of using timeout parameters was that people will always hard > > code > > >> the timeout, and the hard coded timeout is rarely correct because it > has > > >> to > > >> consider different scenarios. For example, users may receive timeout > > >> exception when the group coordinator moves. Having a configuration > with > > >> some reasonable default value will make users' life easier. > > >> > > >> That said, in practice, it seems more useful to have timeout > parameters. > > >> We > > >> have seen some library, using the consumers internally, needs to > provide > > >> an > > >> external flexible timeout interface. Also, user can easily hard code a > > >> value to get the same as a config based solution. > > >> > > >> The KIP looks good overall. A few comments: > > >> > > >> 1. There are a few other blocking methods that are not included, e.g. > > >> offsetsForTimes(), beginningOffsets(), endOffsets(). Is there any > > reason? > > >> > > >> 2. I am wondering can we take the KIP as a chance to clean up our > > timeout > > >> exception(s)? More specifically, instead of reusing TimeoutException, > > can > > >> we introduce a new ClientTimeoutException with different causes, e.g. > > >> UnknownTopicOrPartition, RequestTimeout, LeaderNotAvailable, etc. > > >> As of now, the TimeoutException is used in the following three cases: > > >> > > >> 1. TimeoutException is a subclass of ApiException which indicates > the > > >> exception was returned by the broker. The TimeoutException was > > >> initially > > >> returned by the leaders when replication was not done within the > > >> specified > > >> timeout in the ProduceRequest. It has an error code of 7, which is > > >> returned > > >> by the broker. > > >> 2. When we migrate to Java clients, in Errors definition, we > extended > > >> it > > >> to indicate request timeout, i.e. a request was sent but the > response > > >> was > > >> not received before timeout. In this case, the clients did not > have a > > >> return code from the broker. > > >> 3. Later at some point, we started to use the TimeoutException for > > >> clients method call timeout. It is neither related to any broker > > >> returned > > >> error code, nor to request timeout on the wire. > > >> > > >> Due to the various interpretations, users can easily be confused. As > an > > >> example, when a timeout is thrown with "Failed to refresh metadata in > X > > >> ms", it is hard to tell what exactly happened. Since we are changing > the > > >> API here, it would be good to avoid introducing more ambiguity and see > > >> whether this can be improved. It would be at least one step forward to > > >> remove the usage of case 3. > > >> > > >> Thanks, > > >> > > >> Jiangjie (Becket) Qin > > >> > > >> > > >> > > >> > > >> On Mon, Mar 26, 2018 at 5:50 PM, Guozhang Wang <wangg...@gmail.com> > > >> wrote: > > >> > > >> > @Richard: TimeoutException inherits from RetriableException which > > >> inherits > > >> > from ApiException. So users should explicitly try to capture > > >> > RetriableException in their code and handle the exception. > > >> > > > >> > @Isamel, Ewen: I'm trying to push progress forward on this one, are > we > > >> now > > >> > on the same page for using function parameters than configs? > > >> > > > >> > > > >> > Guozhang > > >> > > > >> > > > >> > On Fri, Mar 23, 2018 at 4:42 PM, Ismael Juma <ism...@juma.me.uk> > > wrote: > > >> > > > >> > > Hi Ewen, > > >> > > > > >> > > Yeah, I mentioned KAFKA-2391 where some of this was discussed. Jay > > was > > >> > > against having timeouts in the methods at the time. However, as > > Jason > > >> > said > > >> > > offline, we did end up with a timeout parameter in `poll`. > > >> > > > > >> > > Ismael > > >> > > > > >> > > On Fri, Mar 23, 2018 at 4:26 PM, Ewen Cheslack-Postava < > > >> > e...@confluent.io> > > >> > > wrote: > > >> > > > > >> > > > Regarding the flexibility question, has someone tried to dig up > > the > > >> > > > discussion of the new consumer APIs when they were being > written? > > I > > >> > > vaguely > > >> > > > recall these exact questions about using APIs vs configs and > > >> > flexibility > > >> > > vs > > >> > > > bloating the API surface area having already been discussed. > (Not > > >> that > > >> > we > > >> > > > shouldn't revisit, just that it might also be a faster way to > get > > >> to a > > >> > > full > > >> > > > understanding of the options, concerns, and tradeoffs). > > >> > > > > > >> > > > -Ewen > > >> > > > > > >> > > > On Thu, Mar 22, 2018 at 7:19 AM, Richard Yu < > > >> > yohan.richard...@gmail.com> > > >> > > > wrote: > > >> > > > > > >> > > > > I do have one question though: in the current KIP, throwing > > >> > > > > TimeoutException to mark > > >> > > > > that time limit is exceeded is applied to all new methods > > >> introduced > > >> > in > > >> > > > > this proposal. > > >> > > > > However, how would users respond when a TimeoutException > (since > > >> it is > > >> > > > > considered > > >> > > > > a RuntimeException)? > > >> > > > > > > >> > > > > Thanks, > > >> > > > > Richard > > >> > > > > > > >> > > > > > > >> > > > > > > >> > > > > On Mon, Mar 19, 2018 at 6:10 PM, Richard Yu < > > >> > > yohan.richard...@gmail.com> > > >> > > > > wrote: > > >> > > > > > > >> > > > > > Hi Ismael, > > >> > > > > > > > >> > > > > > You have a great point. Since most of the methods in this > KIP > > >> have > > >> > > > > similar > > >> > > > > > callbacks (position() and committed() both use > > >> > > fetchCommittedOffsets(), > > >> > > > > > and > > >> > > > > > commitSync() is similar to position(), except just updating > > >> > offsets), > > >> > > > the > > >> > > > > > amount of time > > >> > > > > > they block should be also about equal. > > >> > > > > > > > >> > > > > > However, I think that we need to take into account a couple > of > > >> > > things. > > >> > > > > For > > >> > > > > > starters, > > >> > > > > > if the new methods were all reliant on one config, there is > > >> > > likelihood > > >> > > > > > that the > > >> > > > > > shortcomings for this approach would be similar to what we > > >> faced if > > >> > > we > > >> > > > > let > > >> > > > > > request.timeout.ms control all method timeouts. In > > comparison, > > >> > > adding > > >> > > > > > overloads > > >> > > > > > does not have this problem. > > >> > > > > > > > >> > > > > > If you have further thoughts, please let me know. > > >> > > > > > > > >> > > > > > Richard > > >> > > > > > > > >> > > > > > > > >> > > > > > On Mon, Mar 19, 2018 at 5:12 PM, Ismael Juma < > > ism...@juma.me.uk > > >> > > > >> > > > wrote: > > >> > > > > > > > >> > > > > >> Hi, > > >> > > > > >> > > >> > > > > >> An option that is not currently covered in the KIP is to > > have a > > >> > > > separate > > >> > > > > >> config max.block.ms, which is similar to the producer > config > > >> with > > >> > > the > > >> > > > > >> same > > >> > > > > >> name. This came up during the KAFKA-2391 discussion. I > think > > >> it's > > >> > > > clear > > >> > > > > >> that we can't rely on request.timeout.ms, so the decision > is > > >> > > between > > >> > > > > >> adding > > >> > > > > >> overloads or adding a new config. People seemed to be > leaning > > >> > > towards > > >> > > > > the > > >> > > > > >> latter in KAFKA-2391, but Jason makes a good point that the > > >> > > overloads > > >> > > > > are > > >> > > > > >> more flexible. A couple of questions from me: > > >> > > > > >> > > >> > > > > >> 1. Do we need the additional flexibility? > > >> > > > > >> 2. If we do, do we need it for every blocking method? > > >> > > > > >> > > >> > > > > >> Ismael > > >> > > > > >> > > >> > > > > >> On Mon, Mar 19, 2018 at 5:03 PM, Richard Yu < > > >> > > > yohan.richard...@gmail.com > > >> > > > > > > > >> > > > > >> wrote: > > >> > > > > >> > > >> > > > > >> > Hi Guozhang, > > >> > > > > >> > > > >> > > > > >> > I made some clarifications to KIP-266, namely: > > >> > > > > >> > 1. Stated more specifically that commitSync will accept > > user > > >> > > input. > > >> > > > > >> > 2. fetchCommittedOffsets(): Made its role in blocking > more > > >> clear > > >> > > to > > >> > > > > the > > >> > > > > >> > reader. > > >> > > > > >> > 3. Sketched what would happen when time limit is > exceeded. > > >> > > > > >> > > > >> > > > > >> > These changes should make the KIP easier to understand. > > >> > > > > >> > > > >> > > > > >> > Cheers, > > >> > > > > >> > Richard > > >> > > > > >> > > > >> > > > > >> > On Mon, Mar 19, 2018 at 9:33 AM, Guozhang Wang < > > >> > > wangg...@gmail.com> > > >> > > > > >> wrote: > > >> > > > > >> > > > >> > > > > >> > > Hi Richard, > > >> > > > > >> > > > > >> > > > > >> > > I made a pass over the KIP again, some more > > clarifications > > >> / > > >> > > > > comments: > > >> > > > > >> > > > > >> > > > > >> > > 1. seek() call itself is not blocking, only the > following > > >> > poll() > > >> > > > > call > > >> > > > > >> may > > >> > > > > >> > > be blocking as the actually metadata rq will happen. > > >> > > > > >> > > > > >> > > > > >> > > 2. I saw you did not include Consumer.partitionFor(), > > >> > > > > >> > > Consumer.OffsetAndTimestamp() and Consumer.listTopics() > > in > > >> > your > > >> > > > KIP. > > >> > > > > >> > After > > >> > > > > >> > > a second thought, I think this may be a better idea to > > not > > >> > > tackle > > >> > > > > >> them in > > >> > > > > >> > > the same KIP, and probably we should consider whether > we > > >> would > > >> > > > > change > > >> > > > > >> the > > >> > > > > >> > > behavior or not in another discussion. So I agree to > not > > >> > include > > >> > > > > them. > > >> > > > > >> > > > > >> > > > > >> > > 3. In your wiki you mentioned "Another change shall be > > >> made to > > >> > > > > >> > > KafkaConsumer#poll(), due to its call to > > >> > updateFetchPositions() > > >> > > > > which > > >> > > > > >> > > blocks indefinitely." This part may a bit obscure to > most > > >> > > readers > > >> > > > > >> who's > > >> > > > > >> > not > > >> > > > > >> > > familiar with the KafkaConsumer internals, could you > > please > > >> > add > > >> > > > more > > >> > > > > >> > > elaborations. More specifically, I think the root > causes > > of > > >> > the > > >> > > > > public > > >> > > > > >> > APIs > > >> > > > > >> > > mentioned are a bit different while the KIP's > explanation > > >> > sounds > > >> > > > > like > > >> > > > > >> > they > > >> > > > > >> > > are due to the same reason: > > >> > > > > >> > > > > >> > > > > >> > > 3.1 fetchCommittedOffsets(): this internal call will > > block > > >> > > forever > > >> > > > > if > > >> > > > > >> the > > >> > > > > >> > > committed offsets cannot be fetched successfully and > > affect > > >> > > > > position() > > >> > > > > >> > and > > >> > > > > >> > > committed(). We need to break out of its internal while > > >> loop. > > >> > > > > >> > > 3.2 position() itself will while loop when offsets > cannot > > >> be > > >> > > > > >> retrieved in > > >> > > > > >> > > the underlying async call. We need to break out this > > while > > >> > loop. > > >> > > > > >> > > 3.3 commitSync() passed Long.MAX_VALUE as the timeout > > >> value, > > >> > we > > >> > > > > should > > >> > > > > >> > take > > >> > > > > >> > > the user specified timeouts when applicable. > > >> > > > > >> > > > > >> > > > > >> > > > > >> > > > > >> > > > > >> > > > > >> > > Guozhang > > >> > > > > >> > > > > >> > > > > >> > > On Sat, Mar 17, 2018 at 4:44 PM, Richard Yu < > > >> > > > > >> yohan.richard...@gmail.com> > > >> > > > > >> > > wrote: > > >> > > > > >> > > > > >> > > > > >> > > > Actually, what I said above is inaccurate. In > > >> > > > > >> > > > testSeekAndCommitWithBrokerFailures, > > >> > TestUtils.waitUntilTrue > > >> > > > > >> blocks, > > >> > > > > >> > not > > >> > > > > >> > > > seek. > > >> > > > > >> > > > My assumption is that seek did not update correctly. > I > > >> will > > >> > be > > >> > > > > >> digging > > >> > > > > >> > > > further into this. > > >> > > > > >> > > > > > >> > > > > >> > > > > > >> > > > > >> > > > > > >> > > > > >> > > > On Sat, Mar 17, 2018 at 4:16 PM, Richard Yu < > > >> > > > > >> > yohan.richard...@gmail.com> > > >> > > > > >> > > > wrote: > > >> > > > > >> > > > > > >> > > > > >> > > > > One more thing: when looking through tests, I have > > >> > realized > > >> > > > that > > >> > > > > >> > seek() > > >> > > > > >> > > > > methods can potentially block indefinitely. As you > > well > > >> > > know, > > >> > > > > >> seek() > > >> > > > > >> > is > > >> > > > > >> > > > > called when pollOnce() or position() is active. > Thus, > > >> if > > >> > > > > >> position() > > >> > > > > >> > > > blocks > > >> > > > > >> > > > > indefinitely, then so would seek(). Should bounding > > >> seek() > > >> > > > also > > >> > > > > be > > >> > > > > >> > > > included > > >> > > > > >> > > > > in this KIP? > > >> > > > > >> > > > > > > >> > > > > >> > > > > Thanks, Richard > > >> > > > > >> > > > > > > >> > > > > >> > > > > On Sat, Mar 17, 2018 at 1:16 PM, Richard Yu < > > >> > > > > >> > > yohan.richard...@gmail.com> > > >> > > > > >> > > > > wrote: > > >> > > > > >> > > > > > > >> > > > > >> > > > >> Thanks for the advice, Jason > > >> > > > > >> > > > >> > > >> > > > > >> > > > >> I have modified KIP-266 to include the java doc > for > > >> > > > committed() > > >> > > > > >> and > > >> > > > > >> > > > other > > >> > > > > >> > > > >> blocking methods, and I also > > >> > > > > >> > > > >> mentioned poll() which will also be bounded. Let > me > > >> know > > >> > if > > >> > > > > >> there is > > >> > > > > >> > > > >> anything else. :) > > >> > > > > >> > > > >> > > >> > > > > >> > > > >> Sincerely, Richard > > >> > > > > >> > > > >> > > >> > > > > >> > > > >> > > >> > > > > >> > > > >> > > >> > > > > >> > > > >> > > >> > > > > >> > > > >> > > >> > > > > >> > > > >> On Sat, Mar 17, 2018 at 12:00 PM, Jason Gustafson > < > > >> > > > > >> > ja...@confluent.io > > >> > > > > >> > > > > > >> > > > > >> > > > >> wrote: > > >> > > > > >> > > > >> > > >> > > > > >> > > > >>> Hi Richard, > > >> > > > > >> > > > >>> > > >> > > > > >> > > > >>> Thanks for the updates. I'm really glad you > picked > > >> this > > >> > > up. > > >> > > > A > > >> > > > > >> > couple > > >> > > > > >> > > > >>> minor > > >> > > > > >> > > > >>> comments: > > >> > > > > >> > > > >>> > > >> > > > > >> > > > >>> 1. Can you list the full set of new APIs > explicitly > > >> in > > >> > the > > >> > > > > KIP? > > >> > > > > >> > > > >>> Currently I > > >> > > > > >> > > > >>> only see the javadoc for `position()`. > > >> > > > > >> > > > >>> > > >> > > > > >> > > > >>> 2. We should consider adding `TimeUnit` to the > new > > >> > methods > > >> > > > to > > >> > > > > >> avoid > > >> > > > > >> > > > unit > > >> > > > > >> > > > >>> confusion. I know it's inconsistent with the > poll() > > >> API, > > >> > > > but I > > >> > > > > >> > think > > >> > > > > >> > > it > > >> > > > > >> > > > >>> was > > >> > > > > >> > > > >>> probably a mistake not to include it there, so > > better > > >> > not > > >> > > to > > >> > > > > >> double > > >> > > > > >> > > > down > > >> > > > > >> > > > >>> on > > >> > > > > >> > > > >>> that mistake. And note that we do already have > > >> > > `close(long, > > >> > > > > >> > > TimeUnit)`. > > >> > > > > >> > > > >>> > > >> > > > > >> > > > >>> Other than that, I think the current KIP seems > > >> > reasonable. > > >> > > > > >> > > > >>> > > >> > > > > >> > > > >>> Thanks, > > >> > > > > >> > > > >>> Jason > > >> > > > > >> > > > >>> > > >> > > > > >> > > > >>> On Wed, Mar 14, 2018 at 5:00 PM, Richard Yu < > > >> > > > > >> > > > yohan.richard...@gmail.com> > > >> > > > > >> > > > >>> wrote: > > >> > > > > >> > > > >>> > > >> > > > > >> > > > >>> > Note to all: I have included bounding > > commitSync() > > >> and > > >> > > > > >> > committed() > > >> > > > > >> > > in > > >> > > > > >> > > > >>> this > > >> > > > > >> > > > >>> > KIP. > > >> > > > > >> > > > >>> > > > >> > > > > >> > > > >>> > On Sun, Mar 11, 2018 at 5:05 PM, Richard Yu < > > >> > > > > >> > > > >>> yohan.richard...@gmail.com> > > >> > > > > >> > > > >>> > wrote: > > >> > > > > >> > > > >>> > > > >> > > > > >> > > > >>> > > Hi all, > > >> > > > > >> > > > >>> > > > > >> > > > > >> > > > >>> > > I updated the KIP where overloading > position() > > is > > >> > now > > >> > > > the > > >> > > > > >> > favored > > >> > > > > >> > > > >>> > approach. > > >> > > > > >> > > > >>> > > Bounding position() using requestTimeoutMs > has > > >> been > > >> > > > listed > > >> > > > > >> as > > >> > > > > >> > > > >>> rejected. > > >> > > > > >> > > > >>> > > > > >> > > > > >> > > > >>> > > Any thoughts? > > >> > > > > >> > > > >>> > > > > >> > > > > >> > > > >>> > > On Tue, Mar 6, 2018 at 6:00 PM, Guozhang > Wang < > > >> > > > > >> > > wangg...@gmail.com> > > >> > > > > >> > > > >>> > wrote: > > >> > > > > >> > > > >>> > > > > >> > > > > >> > > > >>> > >> I agree that adding the overloads is most > > >> flexible. > > >> > > But > > >> > > > > >> going > > >> > > > > >> > > for > > >> > > > > >> > > > >>> that > > >> > > > > >> > > > >>> > >> direction we'd do that for all the blocking > > call > > >> > that > > >> > > > > I've > > >> > > > > >> > > listed > > >> > > > > >> > > > >>> above, > > >> > > > > >> > > > >>> > >> with this timeout value covering the > > end-to-end > > >> > > waiting > > >> > > > > >> time. > > >> > > > > >> > > > >>> > >> > > >> > > > > >> > > > >>> > >> > > >> > > > > >> > > > >>> > >> Guozhang > > >> > > > > >> > > > >>> > >> > > >> > > > > >> > > > >>> > >> On Tue, Mar 6, 2018 at 10:02 AM, Ted Yu < > > >> > > > > >> yuzhih...@gmail.com> > > >> > > > > >> > > > >>> wrote: > > >> > > > > >> > > > >>> > >> > > >> > > > > >> > > > >>> > >> > bq. The most flexible option is to add > > >> overloads > > >> > to > > >> > > > the > > >> > > > > >> > > consumer > > >> > > > > >> > > > >>> > >> > > > >> > > > > >> > > > >>> > >> > This option is flexible. > > >> > > > > >> > > > >>> > >> > > > >> > > > > >> > > > >>> > >> > Looking at the tail of SPARK-18057, Spark > > dev > > >> > > voiced > > >> > > > > the > > >> > > > > >> > same > > >> > > > > >> > > > >>> choice. > > >> > > > > >> > > > >>> > >> > > > >> > > > > >> > > > >>> > >> > +1 for adding overload with timeout > > parameter. > > >> > > > > >> > > > >>> > >> > > > >> > > > > >> > > > >>> > >> > Cheers > > >> > > > > >> > > > >>> > >> > > > >> > > > > >> > > > >>> > >> > On Mon, Mar 5, 2018 at 2:42 PM, Jason > > >> Gustafson < > > >> > > > > >> > > > >>> ja...@confluent.io> > > >> > > > > >> > > > >>> > >> > wrote: > > >> > > > > >> > > > >>> > >> > > > >> > > > > >> > > > >>> > >> > > @Guozhang I probably have suggested all > > >> options > > >> > > at > > >> > > > > some > > >> > > > > >> > > point > > >> > > > > >> > > > or > > >> > > > > >> > > > >>> > >> another, > > >> > > > > >> > > > >>> > >> > > including most recently, the current > KIP! > > I > > >> was > > >> > > > > >> thinking > > >> > > > > >> > > that > > >> > > > > >> > > > >>> > >> practically > > >> > > > > >> > > > >>> > >> > > speaking, the request timeout defines > how > > >> long > > >> > > the > > >> > > > > >> user is > > >> > > > > >> > > > >>> willing > > >> > > > > >> > > > >>> > to > > >> > > > > >> > > > >>> > >> > wait > > >> > > > > >> > > > >>> > >> > > for a response. The consumer doesn't > > really > > >> > have > > >> > > a > > >> > > > > >> complex > > >> > > > > >> > > > send > > >> > > > > >> > > > >>> > >> process > > >> > > > > >> > > > >>> > >> > > like the producer for any of these APIs, > > so > > >> I > > >> > > > wasn't > > >> > > > > >> sure > > >> > > > > >> > > how > > >> > > > > >> > > > >>> much > > >> > > > > >> > > > >>> > >> > benefit > > >> > > > > >> > > > >>> > >> > > there would be from having more granular > > >> > control > > >> > > > over > > >> > > > > >> > > timeouts > > >> > > > > >> > > > >>> (in > > >> > > > > >> > > > >>> > the > > >> > > > > >> > > > >>> > >> > end, > > >> > > > > >> > > > >>> > >> > > KIP-91 just adds a single timeout to > > control > > >> > the > > >> > > > > whole > > >> > > > > >> > > send). > > >> > > > > >> > > > >>> That > > >> > > > > >> > > > >>> > >> said, > > >> > > > > >> > > > >>> > >> > it > > >> > > > > >> > > > >>> > >> > > might indeed be better to avoid > > overloading > > >> the > > >> > > > > config > > >> > > > > >> as > > >> > > > > >> > > you > > >> > > > > >> > > > >>> > suggest > > >> > > > > >> > > > >>> > >> > since > > >> > > > > >> > > > >>> > >> > > at least it avoids inconsistency with > the > > >> > > > producer's > > >> > > > > >> > usage. > > >> > > > > >> > > > >>> > >> > > > > >> > > > > >> > > > >>> > >> > > The most flexible option is to add > > >> overloads to > > >> > > the > > >> > > > > >> > consumer > > >> > > > > >> > > > so > > >> > > > > >> > > > >>> that > > >> > > > > >> > > > >>> > >> > users > > >> > > > > >> > > > >>> > >> > > can pass the timeout directly. I'm not > > sure > > >> if > > >> > > that > > >> > > > > is > > >> > > > > >> > more > > >> > > > > >> > > or > > >> > > > > >> > > > >>> less > > >> > > > > >> > > > >>> > >> > > annoying than a new config, but I've > found > > >> > config > > >> > > > > >> > timeouts a > > >> > > > > >> > > > >>> little > > >> > > > > >> > > > >>> > >> > > constraining in practice. For example, I > > >> could > > >> > > > > imagine > > >> > > > > >> > users > > >> > > > > >> > > > >>> wanting > > >> > > > > >> > > > >>> > >> to > > >> > > > > >> > > > >>> > >> > > wait longer for an offset commit > operation > > >> > than a > > >> > > > > >> position > > >> > > > > >> > > > >>> lookup; > > >> > > > > >> > > > >>> > if > > >> > > > > >> > > > >>> > >> the > > >> > > > > >> > > > >>> > >> > > latter isn't timely, users can just > pause > > >> the > > >> > > > > partition > > >> > > > > >> > and > > >> > > > > >> > > > >>> continue > > >> > > > > >> > > > >>> > >> > > fetching on others. If you cannot commit > > >> > offsets, > > >> > > > > >> however, > > >> > > > > >> > > it > > >> > > > > >> > > > >>> might > > >> > > > > >> > > > >>> > be > > >> > > > > >> > > > >>> > >> > > safer for an application to wait > > >> availability > > >> > of > > >> > > > the > > >> > > > > >> > > > coordinator > > >> > > > > >> > > > >>> > than > > >> > > > > >> > > > >>> > >> > > continuing. > > >> > > > > >> > > > >>> > >> > > > > >> > > > > >> > > > >>> > >> > > -Jason > > >> > > > > >> > > > >>> > >> > > > > >> > > > > >> > > > >>> > >> > > On Sun, Mar 4, 2018 at 10:14 PM, > Guozhang > > >> Wang > > >> > < > > >> > > > > >> > > > >>> wangg...@gmail.com> > > >> > > > > >> > > > >>> > >> > wrote: > > >> > > > > >> > > > >>> > >> > > > > >> > > > > >> > > > >>> > >> > > > Hello Richard, > > >> > > > > >> > > > >>> > >> > > > > > >> > > > > >> > > > >>> > >> > > > Thanks for the proposed KIP. I have a > > >> couple > > >> > of > > >> > > > > >> general > > >> > > > > >> > > > >>> comments: > > >> > > > > >> > > > >>> > >> > > > > > >> > > > > >> > > > >>> > >> > > > 1. I'm not sure if piggy-backing the > > >> timeout > > >> > > > > >> exception > > >> > > > > >> > on > > >> > > > > >> > > > the > > >> > > > > >> > > > >>> > >> > > > existing requestTimeoutMs configured > in > > " > > >> > > > > >> > > request.timeout.ms > > >> > > > > >> > > > " > > >> > > > > >> > > > >>> is a > > >> > > > > >> > > > >>> > >> good > > >> > > > > >> > > > >>> > >> > > > idea > > >> > > > > >> > > > >>> > >> > > > since a) it is a general config that > > >> applies > > >> > > for > > >> > > > > all > > >> > > > > >> > types > > >> > > > > >> > > > of > > >> > > > > >> > > > >>> > >> requests, > > >> > > > > >> > > > >>> > >> > > and > > >> > > > > >> > > > >>> > >> > > > 2) using it to cover all the phases of > > an > > >> API > > >> > > > call, > > >> > > > > >> > > > including > > >> > > > > >> > > > >>> > >> network > > >> > > > > >> > > > >>> > >> > > round > > >> > > > > >> > > > >>> > >> > > > trip and potential metadata refresh is > > >> shown > > >> > to > > >> > > > not > > >> > > > > >> be a > > >> > > > > >> > > > good > > >> > > > > >> > > > >>> > idea, > > >> > > > > >> > > > >>> > >> as > > >> > > > > >> > > > >>> > >> > > > illustrated in KIP-91: > > >> > > > > >> > > > >>> > >> > > > > > >> > > > > >> > > > >>> > >> > > > https://cwiki.apache.org/confl > > >> > > > > >> uence/display/KAFKA/KIP- > > >> > > > > >> > > > >>> > >> > > > 91+Provide+Intuitive+User+ > > >> > > > Timeouts+in+The+Producer > > >> > > > > >> > > > >>> > >> > > > > > >> > > > > >> > > > >>> > >> > > > In fact, I think in KAFKA-4879 which > is > > >> aimed > > >> > > for > > >> > > > > the > > >> > > > > >> > same > > >> > > > > >> > > > >>> issue > > >> > > > > >> > > > >>> > as > > >> > > > > >> > > > >>> > >> > > > KAFKA-6608, > > >> > > > > >> > > > >>> > >> > > > Jason has suggested we use a new > config > > >> for > > >> > the > > >> > > > > API. > > >> > > > > >> > Maybe > > >> > > > > >> > > > >>> this > > >> > > > > >> > > > >>> > >> would > > >> > > > > >> > > > >>> > >> > be > > >> > > > > >> > > > >>> > >> > > a > > >> > > > > >> > > > >>> > >> > > > more intuitive manner than reusing the > > >> > > > > >> > request.timeout.ms > > >> > > > > >> > > > >>> config. > > >> > > > > >> > > > >>> > >> > > > > > >> > > > > >> > > > >>> > >> > > > > > >> > > > > >> > > > >>> > >> > > > 2. Besides the Consumer.position() > call, > > >> > there > > >> > > > are > > >> > > > > a > > >> > > > > >> > > couple > > >> > > > > >> > > > of > > >> > > > > >> > > > >>> > more > > >> > > > > >> > > > >>> > >> > > > blocking calls today that could result > > in > > >> > > > infinite > > >> > > > > >> > > blocking: > > >> > > > > >> > > > >>> > >> > > > Consumer.commitSync() and > > >> > Consumer.committed(), > > >> > > > > >> should > > >> > > > > >> > > they > > >> > > > > >> > > > be > > >> > > > > >> > > > >>> > >> > considered > > >> > > > > >> > > > >>> > >> > > > in this KIP as well? > > >> > > > > >> > > > >>> > >> > > > > > >> > > > > >> > > > >>> > >> > > > 3. There are a few other APIs that are > > >> today > > >> > > > > relying > > >> > > > > >> on > > >> > > > > >> > > > >>> > >> > > request.timeout.ms > > >> > > > > >> > > > >>> > >> > > > already for breaking the infinite > > >> blocking, > > >> > > > namely > > >> > > > > >> > > > >>> > >> > > Consumer.partitionFor(), > > >> > > > > >> > > > >>> > >> > > > Consumer.OffsetAndTimestamp() and > > >> > > > > >> Consumer.listTopics(), > > >> > > > > >> > > if > > >> > > > > >> > > > >>> we are > > >> > > > > >> > > > >>> > >> > making > > >> > > > > >> > > > >>> > >> > > > the other blocking calls to be > relying a > > >> new > > >> > > > config > > >> > > > > >> as > > >> > > > > >> > > > >>> suggested > > >> > > > > >> > > > >>> > in > > >> > > > > >> > > > >>> > >> 1) > > >> > > > > >> > > > >>> > >> > > > above, should we also change the > > >> semantics of > > >> > > > these > > >> > > > > >> API > > >> > > > > >> > > > >>> functions > > >> > > > > >> > > > >>> > >> for > > >> > > > > >> > > > >>> > >> > > > consistency? > > >> > > > > >> > > > >>> > >> > > > > > >> > > > > >> > > > >>> > >> > > > > > >> > > > > >> > > > >>> > >> > > > Guozhang > > >> > > > > >> > > > >>> > >> > > > > > >> > > > > >> > > > >>> > >> > > > > > >> > > > > >> > > > >>> > >> > > > > > >> > > > > >> > > > >>> > >> > > > > > >> > > > > >> > > > >>> > >> > > > On Sun, Mar 4, 2018 at 11:13 AM, > Richard > > >> Yu < > > >> > > > > >> > > > >>> > >> > yohan.richard...@gmail.com> > > >> > > > > >> > > > >>> > >> > > > wrote: > > >> > > > > >> > > > >>> > >> > > > > > >> > > > > >> > > > >>> > >> > > > > Hi all, > > >> > > > > >> > > > >>> > >> > > > > > > >> > > > > >> > > > >>> > >> > > > > I would like to discuss a potential > > >> change > > >> > > > which > > >> > > > > >> would > > >> > > > > >> > > be > > >> > > > > >> > > > >>> made > > >> > > > > >> > > > >>> > to > > >> > > > > >> > > > >>> > >> > > > > KafkaConsumer: > > >> > > > > >> > > > >>> > >> > > > > https://cwiki.apache.org/ > > >> > > > > confluence/pages/viewpage > > >> > > > > >> . > > >> > > > > >> > > > >>> > >> > > > action?pageId=75974886 > > >> > > > > >> > > > >>> > >> > > > > > > >> > > > > >> > > > >>> > >> > > > > Thanks, > > >> > > > > >> > > > >>> > >> > > > > Richard Yu > > >> > > > > >> > > > >>> > >> > > > > > > >> > > > > >> > > > >>> > >> > > > > > >> > > > > >> > > > >>> > >> > > > > > >> > > > > >> > > > >>> > >> > > > > > >> > > > > >> > > > >>> > >> > > > -- > > >> > > > > >> > > > >>> > >> > > > -- Guozhang > > >> > > > > >> > > > >>> > >> > > > > > >> > > > > >> > > > >>> > >> > > > > >> > > > > >> > > > >>> > >> > > > >> > > > > >> > > > >>> > >> > > >> > > > > >> > > > >>> > >> > > >> > > > > >> > > > >>> > >> > > >> > > > > >> > > > >>> > >> -- > > >> > > > > >> > > > >>> > >> -- Guozhang > > >> > > > > >> > > > >>> > >> > > >> > > > > >> > > > >>> > > > > >> > > > > >> > > > >>> > > > > >> > > > > >> > > > >>> > > > >> > > > > >> > > > >>> > > >> > > > > >> > > > >> > > >> > > > > >> > > > >> > > >> > > > > >> > > > > > > >> > > > > >> > > > > > >> > > > > >> > > > > >> > > > > >> > > > > >> > > > > >> > > > > >> > > > > >> > > -- > > >> > > > > >> > > -- Guozhang > > >> > > > > >> > > > > >> > > > > >> > > > >> > > > > >> > > >> > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > > >> > > > >> > -- > > >> > -- Guozhang > > >> > > > >> > > > > > > > > > > > > -- > -- Guozhang >
