Thanks for the discussion and voting. KIP-219 has passed with +3 binding votes (Becket, Jun, Rajini).
On Thu, Jan 18, 2018 at 1:32 AM, Rajini Sivaram <rajinisiva...@gmail.com> wrote: > Hi Becket, > > Thanks for the update. Yes, it does address my concern. > > +1 (binding) > > Regards, > > Rajini > > On Wed, Jan 17, 2018 at 5:24 PM, Becket Qin <becket....@gmail.com> wrote: > > > Actually returning an empty fetch request may still be useful to reduce > the > > throttle time due to request quota violation because the FetchResponse > send > > time will be less. I just updated the KIP. > > > > Rajini, does that address your concern? > > > > On Tue, Jan 16, 2018 at 7:01 PM, Becket Qin <becket....@gmail.com> > wrote: > > > > > Thanks for the reply, Jun. > > > > > > Currently the byte rate quota does not apply to HeartbeatRequest, > > > JoinGroupRequest/SyncGroupRequest. So the only case those requests are > > > throttled is because the request quota is violated. In that case, the > > > throttle time does not really matter whether we return a full > > FetchResponse > > > or an empty one. Would it be more consistent if we throttle based on > the > > > actual throttle time / channel mute time? > > > > > > Thanks, > > > > > > Jiangjie (Becket) Qin > > > > > > On Tue, Jan 16, 2018 at 3:45 PM, Jun Rao <j...@confluent.io> wrote: > > > > > >> Hi, Jiangjie, > > >> > > >> You are right that the heartbeat is done in a channel different from > the > > >> fetch request. I think it's still useful to return an empty fetch > > response > > >> when the quota is violated. This way, the throttle time for the > > heartbeat > > >> request won't be large. I agree that we can just mute the channel for > > the > > >> fetch request for the throttle time computed based on a full fetch > > >> response. This probably also partially addresses Rajini's #1 concern. > > >> > > >> Thanks, > > >> > > >> Jun > > >> > > >> On Mon, Jan 15, 2018 at 9:27 PM, Becket Qin <becket....@gmail.com> > > wrote: > > >> > > >> > Hi Rajini, > > >> > > > >> > Thanks for the comments. Pleas see the reply inline. > > >> > > > >> > Hi Jun, > > >> > > > >> > Thinking about the consumer rebalance case a bit more, I am not sure > > if > > >> we > > >> > need to worry about the delayed rebalance due to quota violation or > > not. > > >> > The rebalance actually uses a separate channel to coordinator. > > Therefore > > >> > unless the request quota is hit, the rebalance won't be throttled. > > Even > > >> if > > >> > request quota is hit, it seems unlikely to be delayed long. So it > > looks > > >> > that we don't need to unmute the channel earlier than needed. Does > > this > > >> > address your concern? > > >> > > > >> > Thanks, > > >> > > > >> > Jiangjie (Becket) Qin > > >> > > > >> > On Mon, Jan 15, 2018 at 4:22 AM, Rajini Sivaram < > > >> rajinisiva...@gmail.com> > > >> > wrote: > > >> > > > >> > > Hi Becket, > > >> > > > > >> > > A few questions: > > >> > > > > >> > > 1. KIP says: *Although older client implementations (prior to > > >> knowledge > > >> > of > > >> > > this KIP) will immediately send the next request after the broker > > >> > responds > > >> > > without paying attention to the throttle time field, the broker is > > >> > > protected by virtue of muting the channel for time X. i.e., the > next > > >> > > request will not be processed until the channel is unmuted. * > > >> > > For fetch requests, the response is sent immediately and the mute > > >> time on > > >> > > the broker based on empty fetch response will often be zero > (unlike > > >> the > > >> > > throttle time returned to the client based on non-empty response). > > >> Won't > > >> > > that lead to a tight loop of fetch requests from old clients > > >> > (particularly > > >> > > expensive with SSL)? Wouldn't it be better to retain current > > behaviour > > >> > for > > >> > > old clients? Also, if we change the behaviour for old clients, > > client > > >> > > metrics that track throttle time will report a lot of throttle > > >> unrelated > > >> > to > > >> > > actual throttle time. > > >> > > > > >> > For consumers, if quota is violated, the throttle time on the broker > > >> will > > >> > not be 0. It is just that the throttle time will not be increasing > > >> because > > >> > the consumer will return an empty response in this case. So there > > should > > >> > not be a tight loop. > > >> > > > >> > > > >> > > 2. KIP says: *The usual idle timeout i.e., > connections.max.idle.ms > > >> > > <http://connections.max.idle.ms> will still be honored during the > > >> > throttle > > >> > > time X. This makes sure that the brokers will detect client > > connection > > >> > > closure in a bounded time.* > > >> > > Wouldn't it be better to bound maximum throttle time to > > >> > > *connections.max.idle.ms > > >> > > <http://connections.max.idle.ms>*? If we mute for a time greater > > than > > >> > > *connections.max.idle.ms > > >> > > <http://connections.max.idle.ms>* and then close a client > > connection > > >> > > simply > > >> > > because we had muted it on the broker for a longer throttle time, > we > > >> > force > > >> > > a reconnection and read the next request from the new connection > > >> straight > > >> > > away. This feels the same as a bound on the quota of * > > >> > > connections.max.idle.ms > > >> > > <http://connections.max.idle.ms>*, but with added load on the > > broker > > >> for > > >> > > authenticating another connection (expensive with SSL). > > >> > > > > >> > I think we need to think about the consumer prior to and after this > > KIP > > >> > separately. > > >> > > > >> > For consumer prior to this KIP, even if we unmute the channel after > > >> > connection.max.idle.ms, it is likely that the consumers have > already > > >> > reached request.timeout.ms before that and has reconnected to the > > >> broker. > > >> > So there is no real difference whether we close the throttled > channel > > or > > >> > not. > > >> > > > >> > For consumers after the KIP, because they will honor the throttle > > time, > > >> > they will back off until throttle time is reached. If that throttle > > >> time is > > >> > longer than connection.max.idle.ms, it seems not a big overhead > > because > > >> > there will only be one connection re-establishment in quite a few > > >> minutes. > > >> > Compared with such overhead, it seems more important to honor the > > quota > > >> so > > >> > the broker can survive. > > >> > > > >> > > > >> > > 3. Are we changing the behaviour of network bandwidth quota for > > >> > > Produce/Fetch and retaining current behaviour for request quotas? > > >> > > > > >> > This is going to be applied to all the quota. Including request > > quotas. > > >> > > > >> > > > >> > > > > >> > > Thanks, > > >> > > > > >> > > Rajini > > >> > > > > >> > > > > >> > > > > >> > > On Wed, Jan 10, 2018 at 10:29 PM, Jun Rao <j...@confluent.io> > wrote: > > >> > > > > >> > > > Hi, Jiangjie, > > >> > > > > > >> > > > Thanks for the updated KIP. +1 > > >> > > > > > >> > > > Jun > > >> > > > > > >> > > > On Mon, Jan 8, 2018 at 7:45 PM, Becket Qin < > becket....@gmail.com> > > >> > wrote: > > >> > > > > > >> > > > > Thanks for the comments, Jun. > > >> > > > > > > >> > > > > 1. Good point. > > >> > > > > 2. Also makes sense. Usually the connection.max.idle.ms is > high > > >> > enough > > >> > > > so > > >> > > > > the throttling is impacted. > > >> > > > > > > >> > > > > I have updated the KIP to reflect the changes. > > >> > > > > > > >> > > > > Thanks, > > >> > > > > > > >> > > > > Jiangjie (Becket) Qin > > >> > > > > > > >> > > > > > > >> > > > > On Mon, Jan 8, 2018 at 6:30 PM, Jun Rao <j...@confluent.io> > > wrote: > > >> > > > > > > >> > > > > > Hi, Jiangjie, > > >> > > > > > > > >> > > > > > Sorry for the late response. The proposal sounds good > > overall. A > > >> > > couple > > >> > > > > of > > >> > > > > > minor comments below. > > >> > > > > > > > >> > > > > > 1. For throttling a fetch request, we could potentially just > > >> send > > >> > an > > >> > > > > empty > > >> > > > > > response. We can return a throttle time calculated from a > full > > >> > > > response, > > >> > > > > > but only mute the channel on the server based on a throttle > > time > > >> > > > > calculated > > >> > > > > > based on the empty response. This has the benefit that the > > >> server > > >> > > will > > >> > > > > mute > > >> > > > > > the channel much shorter, which will prevent the consumer > from > > >> > > > > rebalancing > > >> > > > > > when throttled. > > >> > > > > > > > >> > > > > > 2. The wiki says "connections.max.idle.ms should be ignored > > >> during > > >> > > the > > >> > > > > > throttle time X." This has the potential issue that a server > > may > > >> > not > > >> > > > > detect > > >> > > > > > that a client connection is already gone until after an > > >> arbitrary > > >> > > > amount > > >> > > > > of > > >> > > > > > time. Perhaps we could still just close a connection if the > > >> server > > >> > > has > > >> > > > > > muted it for longer than connections.max.idle.ms. This will > > at > > >> > least > > >> > > > > bound > > >> > > > > > the time for a server to detect closed client connections. > > >> > > > > > > > >> > > > > > Thanks, > > >> > > > > > > > >> > > > > > Jun > > >> > > > > > > > >> > > > > > > > >> > > > > > On Mon, Nov 20, 2017 at 5:30 PM, Becket Qin < > > >> becket....@gmail.com> > > >> > > > > wrote: > > >> > > > > > > > >> > > > > > > Hi, > > >> > > > > > > > > >> > > > > > > We would like to start the voting thread for KIP-219. The > > KIP > > >> > > > proposes > > >> > > > > to > > >> > > > > > > improve the quota communication between the brokers and > > >> clients, > > >> > > > > > especially > > >> > > > > > > for cases of long throttling time. > > >> > > > > > > > > >> > > > > > > The KIP wiki is following: > > >> > > > > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP- > > >> > > > > > 219+-+Improve+quota+ > > >> > > > > > > communication > > >> > > > > > > > > >> > > > > > > The discussion thread is here: > > >> > > > > > > http://markmail.org/search/?q=kafka+KIP-219#query:kafka% > > >> > > > > > > 20KIP-219+page:1+mid:ooxabguy7nz7l7zy+state:results > > >> > > > > > > > > >> > > > > > > Thanks, > > >> > > > > > > > > >> > > > > > > Jiangjie (Becket) Qin > > >> > > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > > > > > > > >
