Thanks Crispin! Ismael
On Mon, Jul 24, 2023 at 8:16 PM Crispin Bernier <cbern...@confluent.io.invalid> wrote: > I updated the wiki to include both results along with their average. > > Thank you, > Crispin > > On Mon, Jul 24, 2023 at 10:58 AM Ismael Juma <m...@ismaeljuma.com> wrote: > > > Hi Crispin, > > > > One additional question, the wiki says "The results are averaged over 2 > > runs.". Can you please provide some measure of variance in the > > distribution, i.e. were both results similar to each other for both > cases? > > > > Ismael > > > > On Fri, Jul 21, 2023 at 11:31 AM Ismael Juma <m...@ismaeljuma.com> wrote: > > > > > Thanks for the update Crispin - very helpful to have actual performance > > > data. 2-5% for the default configuration is a bit on the low side for > > this > > > kind of proposal. > > > > > > Ismael > > > > > > On Thu, Jul 20, 2023 at 11:33 PM Crispin Bernier > > > <cbern...@confluent.io.invalid> wrote: > > > > > >> Benchmark numbers have been posted on the KIP, please review. > > >> > > >> On 2023/07/20 13:03:00 Mayank Shekhar Narula wrote: > > >> > Jun > > >> > > > >> > Thanks for the feedback. > > >> > > > >> > Numbers to follow. > > >> > > > >> > If we don't plan to > > >> > > bump up the FetchResponse version, we could just remove the > > reference > > >> to > > >> > > version 16. > > >> > > > >> > Fixed. > > >> > > > >> > On Thu, Jul 20, 2023 at 1:28 AM Jun Rao <ju...@confluent.io.invalid > > > > >> wrote: > > >> > > > >> > > Hi, Mayank, > > >> > > > > >> > > Thanks for the KIP. I agree with others that it would be useful to > > >> see the > > >> > > performance results. Otherwise, just a minor comment. If we don't > > >> plan to > > >> > > bump up the FetchResponse version, we could just remove the > > reference > > >> to > > >> > > version 16. > > >> > > > > >> > > Jun > > >> > > > > >> > > On Wed, Jul 19, 2023 at 2:31 PM Mayank Shekhar Narula < > > >> > > mayanks.nar...@gmail.com> wrote: > > >> > > > > >> > > > Luke > > >> > > > > > >> > > > Thanks for the interest in the KIP. > > >> > > > > > >> > > > But what if the consumer was fetching from the follower? > > >> > > > > > >> > > > We already include `PreferredReadReplica` in the fetch response. > > >> > > > > Should we put the node info of PreferredReadReplica under this > > >> case, > > >> > > > > instead of the leader's info? > > >> > > > > > > >> > > > > > >> > > > PreferredReadReplica is the decided on the leader. Looking at > the > > >> Java > > >> > > > client code, AbstractFetch::selectReadReplica, first fetch > request > > >> goes > > >> > > to > > >> > > > Leader of the partition -> Sends back PreferredReadReplica -> > Next > > >> fetch > > >> > > > uses PreferredReadReplica. So as long as leader is available, > > >> > > > PreferredReadReplica would be found in subsequent fetches. > > >> > > > > > >> > > > Also, under this case, should we include the leader's info in > the > > >> > > response? > > >> > > > > > >> > > > > > >> > > > In this case, I think the follower would fail the fetch if it > > knows > > >> a > > >> > > > different leader. If the follower knows a newer leader, it would > > >> return > > >> > > new > > >> > > > leader information in the response, for the client to act on. > > >> > > > > > >> > > > > > >> > > > Will we include the leader/node info in the response when having > > >> > > > > `UNKNOWN_LEADER_EPOCH` error? > > >> > > > > > >> > > > > > >> > > > My understanding is UNKNOWN_LEADER_EPOCH when a request from a > > >> client > > >> > > has a > > >> > > > newer epoch than the broker. So the client is already up to date > > on > > >> new > > >> > > > leader information, it's the broker that has the catching up to > > do. > > >> I > > >> > > think > > >> > > > there might be some optimisations to make sure the broker > > refreshes > > >> its > > >> > > > metadata quickly, so it can quickly recover to handle requests > > that > > >> > > > previously returned UNKNOWN_LEADER_EPOCH. But this work is > outside > > >> the > > >> > > > scope of this KIP, as for now this KIP focusses on client-side > > >> > > > optimisations. > > >> > > > > > >> > > > Mayank > > >> > > > > > >> > > > On Tue, Jul 18, 2023 at 8:51 AM Luke Chen <sh...@gmail.com> > > wrote: > > >> > > > > > >> > > > > Hi Mayank, > > >> > > > > > > >> > > > > Thanks for the KIP! > > >> > > > > > > >> > > > > Some questions: > > >> > > > > 1. I can see most of the cases we only care about consumer > fetch > > >> from > > >> > > the > > >> > > > > leader. > > >> > > > > But what if the consumer was fetching from the follower? > > >> > > > > We already include `PreferredReadReplica` in the fetch > response. > > >> > > > > Should we put the node info of PreferredReadReplica under this > > >> case, > > >> > > > > instead of the leader's info? > > >> > > > > Also, under this case, should we include the leader's info in > > the > > >> > > > response? > > >> > > > > > > >> > > > > 2. Will we include the leader/node info in the response when > > >> having > > >> > > > > `UNKNOWN_LEADER_EPOCH` error? > > >> > > > > I think it's fine we ignore the `UNKNOWN_LEADER_EPOCH` error > > >> since when > > >> > > > > this happens, the node might have some error which should > > refresh > > >> the > > >> > > > > metadata. On the other hand, it might also be good if we can > > heal > > >> the > > >> > > > node > > >> > > > > soon to do produce/consume works. > > >> > > > > > > >> > > > > > > >> > > > > Thank you. > > >> > > > > Luke > > >> > > > > > > >> > > > > On Tue, Jul 18, 2023 at 2:00 AM Philip Nee <ph...@gmail.com> > > >> > > wrote: > > >> > > > > > > >> > > > > > Hey Mayank: > > >> > > > > > > > >> > > > > > For #1: I think fetch and produce behave a bit differently > on > > >> > > metadata. > > >> > > > > > Maybe it is worth highlighting the changes for each client > in > > >> detail. > > >> > > > In > > >> > > > > > producer did you mean by the metadata timeout before sending > > out > > >> > > > produce > > >> > > > > > requests? For consumer: I think for fetches it requires user > > to > > >> retry > > >> > > > if > > >> > > > > > the position does not exist on the leader. I don't have the > > >> detail on > > >> > > > top > > >> > > > > > of my head, but I think we should lay out these behavioral > > >> changes. > > >> > > > > > > > >> > > > > > For #3: Thanks for the clarification. > > >> > > > > > > > >> > > > > > On Mon, Jul 17, 2023 at 10:39 AM Mayank Shekhar Narula < > > >> > > > > > mayanks.nar...@gmail.com> wrote: > > >> > > > > > > > >> > > > > > > Philip > > >> > > > > > > > > >> > > > > > > 1. Good call out about "poll" behaviour, my understanding > is > > >> the > > >> > > > same. > > >> > > > > I > > >> > > > > > am > > >> > > > > > > assuming it's about the motivation of the KIP. There with > > >> async, my > > >> > > > > > > intention was to convey that the client doesn't wait for > the > > >> > > > > > > metadata-refresh before a subsequent retry of the produce > or > > >> fetch > > >> > > > > > request > > >> > > > > > > that failed due to stale metadata(i.e. going to an old > > >> leader). The > > >> > > > > only > > >> > > > > > > wait client has is the configured retry-delay. > > >> > > > > > > > > >> > > > > > > 2. Yes, in theory other APIs could benefit from this too. > > But > > >> that > > >> > > is > > >> > > > > > > outside of the scope of the KIP. > > >> > > > > > > > > >> > > > > > > 3. Do you mean the response for the Metadata RPC? I think > > >> brokers > > >> > > > > always > > >> > > > > > > have a view of the cluster, although it can be stale,it > > would > > >> > > always > > >> > > > > > return > > >> > > > > > > a leader(whether old or new). > > >> > > > > > > > > >> > > > > > > Mayank > > >> > > > > > > > > >> > > > > > > On Fri, Jul 14, 2023 at 8:53 PM Philip Nee < > ph...@gmail.com > > > > > >> > > > > wrote: > > >> > > > > > > > > >> > > > > > > > Hey Mayank, > > >> > > > > > > > > > >> > > > > > > > Thanks for the KIP. I think this is a great proposal, > and > > >> I'm in > > >> > > > > favor > > >> > > > > > > > of this idea. A few comments: > > >> > > > > > > > > > >> > > > > > > > 1. Claiming metadata refresh is done asynchronously is > > >> > > misleading. > > >> > > > > The > > >> > > > > > > > metadata refresh requires Network Client to be > physically > > >> polled, > > >> > > > > which > > >> > > > > > > is > > >> > > > > > > > done in a separate thread in Producer and Admin Client > > >> (IIRC!) > > >> > > but > > >> > > > > not > > >> > > > > > > > Consumer. > > >> > > > > > > > 2. There are other API calls that might result in > > >> > > > > > NOT_LEADER_OR_FOLLOWER > > >> > > > > > > > response, but it seems like this KIP only wants to > update > > on > > >> > > fetch > > >> > > > > and > > >> > > > > > > > produce. Do we want to make the leader information > > >> available for > > >> > > > > other > > >> > > > > > > API > > >> > > > > > > > calls? > > >> > > > > > > > 3. Do you know what would happen during a leader > election? > > >> I'm > > >> > > not > > >> > > > > sure > > >> > > > > > > > about this process and I wonder if the current metadata > > >> response > > >> > > > uses > > >> > > > > > the > > >> > > > > > > > old leader or null as the leader isn't readily available > > >> yet. > > >> > > > > > > > > > >> > > > > > > > Thanks, > > >> > > > > > > > P > > >> > > > > > > > > > >> > > > > > > > On Fri, Jul 14, 2023 at 11:30 AM Kirk True < > > >> ki...@kirktrue.pro> > > >> > > > > wrote: > > >> > > > > > > > > > >> > > > > > > > > Hi Mayank, > > >> > > > > > > > > > > >> > > > > > > > > > On Jul 14, 2023, at 11:25 AM, Mayank Shekhar Narula > < > > >> > > > > > > > > mayanks.nar...@gmail.com> wrote: > > >> > > > > > > > > > > > >> > > > > > > > > > Kirk > > >> > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > >> Is the requested restructuring of the response > > >> “simply” to > > >> > > > > > preserve > > >> > > > > > > > > bytes, > > >> > > > > > > > > >> or is it possible that the fetch response > > >> could/should/would > > >> > > > > > return > > >> > > > > > > > > >> leadership changes for partitions that we’re > > >> specifically > > >> > > > > > requested? > > >> > > > > > > > > >> > > >> > > > > > > > > > > > >> > > > > > > > > > Moving endpoints to top-level fields would preserve > > >> bytes, > > >> > > > > > otherwise > > >> > > > > > > > the > > >> > > > > > > > > > endpoint-information would be duplicated if included > > >> with the > > >> > > > > > > > > > partition-data in the response. Right now, the > > top-level > > >> > > field > > >> > > > > will > > >> > > > > > > > only > > >> > > > > > > > > be > > >> > > > > > > > > > set in case leader changes for any requested > > >> partitions. But > > >> > > it > > >> > > > > can > > >> > > > > > > be > > >> > > > > > > > > > re-used in the future, for which Jose has a use-case > > in > > >> mind > > >> > > > > shared > > >> > > > > > > up > > >> > > > > > > > in > > >> > > > > > > > > > the thread. KIP is now upto date with endpoint info > > >> being at > > >> > > > > > > top-level. > > >> > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > I didn’t catch before that there was a separate > section > > >> for the > > >> > > > > full > > >> > > > > > > node > > >> > > > > > > > > information, not just the ID and epoch. > > >> > > > > > > > > > > >> > > > > > > > > Thanks! > > >> > > > > > > > > > > >> > > > > > > > > >>> 3. In the future, I may use this information in > the > > >> > > > > > KRaft/Metadata > > >> > > > > > > > > >>> implementation of FETCH. In that implementation > not > > >> all of > > >> > > > the > > >> > > > > > > > > >>> replicas are brokers. > > >> > > > > > > > > >> > > >> > > > > > > > > >> Side point: any references to the change you’re > > >> referring > > >> > > to? > > >> > > > > The > > >> > > > > > > idea > > >> > > > > > > > > of > > >> > > > > > > > > >> non-brokers serving as replicas is blowing my mind > a > > >> bit :) > > >> > > > > > > > > >> > > >> > > > > > > > > >> > > >> > > > > > > > > > Jose, I missed this as well, would love to know more > > >> about > > >> > > > > > non-broker > > >> > > > > > > > > > serving as replica! > > >> > > > > > > > > > -- > > >> > > > > > > > > > Regards, > > >> > > > > > > > > > Mayank Shekhar Narula > > >> > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > >> > > > > > > > > >> > > > > > > -- > > >> > > > > > > Regards, > > >> > > > > > > Mayank Shekhar Narula > > >> > > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > >> > > > > > >> > > > -- > > >> > > > Regards, > > >> > > > Mayank Shekhar Narula > > >> > > > > > >> > > > > >> > > > >> > > > >> > -- > > >> > Regards, > > >> > Mayank Shekhar Narula > > >> > > > > > > > > > >
