Hi Jun, Clarified the meaning of the two metrics. Also updated the KIP.
kafka.log.remote:type=RemoteLogManager, name=RemoteFetchThrottleTime -> The duration of time required at a given moment to bring the observed fetch rate within the allowed limit, by preventing further reads. kafka.log.remote:type=RemoteLogManager, name=RemoteCopyThrottleTime -> The duration of time required at a given moment to bring the observed remote copy rate within the allowed limit, by preventing further copies. Regards. On Wed, Feb 28, 2024 at 12:28 AM Jun Rao <j...@confluent.io.invalid> wrote: > Hi, Abhijeet, > > Thanks for the explanation. Makes sense to me now. > > Just a minor comment. Could you document the exact meaning of the following > two metrics? For example, is the time accumulated? If so, is it from the > start of the broker or over some window? > > kafka.log.remote:type=RemoteLogManager, name=RemoteFetchThrottleTime > kafka.log.remote:type=RemoteLogManager, name=RemoteCopyThrottleTime > > Jun > > On Tue, Feb 27, 2024 at 1:39 AM Abhijeet Kumar <abhijeet.cse....@gmail.com > > > wrote: > > > Hi Jun, > > > > The existing quota system for consumers is designed to throttle the > > consumer if it exceeds the allowed fetch rate. > > The additional quota we want to add works on the broker level. If the > > broker-level remote read quota is being > > exceeded, we prevent additional reads from the remote storage but do not > > prevent local reads for the consumer. > > If the consumer has specified other partitions to read, which can be > served > > from local, it can continue to read those > > partitions. To elaborate more, we make a check for quota exceeded if we > > know a segment needs to be read from > > remote. If the quota is exceeded, we simply skip the partition and move > to > > other segments in the fetch request. > > This way consumers can continue to read the local data as long as they > have > > not exceeded the client-level quota. > > > > Also, when we choose the appropriate consumer-level quota, we would > > typically look at what kind of local fetch > > throughput is supported. If we were to reuse the same consumer quota, we > > should also consider the throughput > > the remote storage supports. The throughput supported by remote may be > > less/more than the throughput supported > > by local (when using a cloud provider, it depends on the plan opted by > the > > user). The consumer quota has to be carefully > > set considering both local and remote throughput. Instead, if we have a > > separate quota, it makes things much simpler > > for the user, since they already know what throughput their remote > storage > > supports. > > > > (Also, thanks for pointing out. I will update the KIP based on the > > discussion) > > > > Regards, > > Abhijeet. > > > > On Tue, Feb 27, 2024 at 2:49 AM Jun Rao <j...@confluent.io.invalid> > wrote: > > > > > Hi, Abhijeet, > > > > > > Sorry for the late reply. It seems that you haven't updated the KIP > based > > > on the discussion? One more comment. > > > > > > 11. Currently, we already have a quota system for both the producers > and > > > consumers. I can understand why we need an additional > > > remote.log.manager.write.quota.default quota. For example, when tier > > > storage is enabled for the first time, there could be a lot of segments > > > that need to be written to the remote storage, even though there is no > > > increase in the produced data. However, I am not sure about an > > > additional remote.log.manager.read.quota.default. The KIP says that the > > > reason is "This may happen when the majority of the consumers start > > reading > > > from the earliest offset of their respective Kafka topics.". However, > > this > > > can happen with or without tier storage and the current quota system > for > > > consumers is designed for solving this exact problem. Could you explain > > the > > > usage of this additional quota? > > > > > > Thanks, > > > > > > Jun > > > > > > On Mon, Feb 12, 2024 at 11:08 AM Abhijeet Kumar < > > > abhijeet.cse....@gmail.com> > > > wrote: > > > > > > > Comments inline > > > > > > > > On Wed, Dec 6, 2023 at 1:12 AM Jun Rao <j...@confluent.io.invalid> > > wrote: > > > > > > > > > Hi, Abhijeet, > > > > > > > > > > Thanks for the KIP. A few comments. > > > > > > > > > > 10. remote.log.manager.write.quota.default: > > > > > 10.1 For other configs, we > > > > > use replica.alter.log.dirs.io.max.bytes.per.second. To be > consistent, > > > > > perhaps this can be sth like > > > > remote.log.manager.write.max.bytes.per.second. > > > > > > > > > > > > > This makes sense, we can rename the following configs to be > consistent. > > > > > > > > Remote.log.manager.write.quota.default -> > > > > remote.log.manager.write.max.bytes.per.second > > > > > > > > Remote.log.manager.read.quota.default -> > > > > remote.log.manager.read.max.bytes.per.second. > > > > > > > > > > > > > > > > > 10.2 Could we list the new metrics associated with the new quota. > > > > > > > > > > > > > We will add the following metrics as mentioned in the other response. > > > > *RemoteFetchThrottleTime* - The amount of time needed to bring the > > > observed > > > > remote fetch rate within the read quota > > > > *RemoteCopyThrottleTime *- The amount of time needed to bring the > > > observed > > > > remote copy rate with the copy quota. > > > > > > > > 10.3 Is this dynamically configurable? If so, could we document the > > > impact > > > > > to tools like kafka-configs.sh and AdminClient? > > > > > > > > > > > > > Yes, the quotas are dynamically configurable. We will add them as > > Dynamic > > > > Broker Configs. Users will be able to change > > > > the following configs using either kafka-configs.sh or AdminClient by > > > > specifying the config name and new value. For eg. > > > > > > > > Using kafka-configs.sh > > > > > > > > bin/kafka-configs.sh --bootstrap-server <bootstrap-server> > > --entity-type > > > > brokers --entity-default --alter --add-config > > > > remote.log.manager.write.max.bytes.per.second=52428800 > > > > > > > > Using AdminClient > > > > > > > > ConfigEntry configEntry = new > > > > ConfigEntry("remote.log.manager.write.max.bytes.per.second", > > "5242800"); > > > > AlterConfigOp alterConfigOp = new AlterConfigOp(configEntry, > > > > AlterConfigOp.OpType.SET); > > > > List<AlterConfigOp> alterConfigOps = > > > > Collections.singletonList(alterConfigOp); > > > > > > > > ConfigResource resource = new > > ConfigResource(ConfigResource.Type.BROKER, > > > > ""); > > > > Map<ConfigResource, Collection<AlterConfigOp>> updateConfig = > > > > ImmutableMap.of(resource, alterConfigOps); > > > > adminClient.incrementalAlterConfigs(updateConfig); > > > > > > > > > > > > > > > > > > Jun > > > > > > > > > > On Tue, Nov 28, 2023 at 2:19 AM Luke Chen <show...@gmail.com> > wrote: > > > > > > > > > > > Hi Abhijeet, > > > > > > > > > > > > Thanks for the KIP! > > > > > > This is an important feature for tiered storage. > > > > > > > > > > > > Some comments: > > > > > > 1. Will we introduce new metrics for this tiered storage quotas? > > > > > > This is important because the admin can know the throttling > status > > by > > > > > > checking the metrics while the remote write/read are slow, like > the > > > > rate > > > > > of > > > > > > uploading/reading byte rate, the throttled time for > upload/read... > > > etc. > > > > > > > > > > > > 2. Could you give some examples for the throttling algorithm in > the > > > KIP > > > > > to > > > > > > explain it? That will make it much clearer. > > > > > > > > > > > > 3. To solve this problem, we can break down the RLMTask into two > > > > smaller > > > > > > tasks - one for segment upload and the other for handling expired > > > > > segments. > > > > > > How do we handle the situation when a segment is still waiting > for > > > > > > offloading while this segment is expired and eligible to be > > deleted? > > > > > > Maybe it'll be easier to not block the RLMTask when quota > exceeded, > > > and > > > > > > just check it each time the RLMTask runs? > > > > > > > > > > > > Thank you. > > > > > > Luke > > > > > > > > > > > > On Wed, Nov 22, 2023 at 6:27 PM Abhijeet Kumar < > > > > > abhijeet.cse....@gmail.com > > > > > > > > > > > > > wrote: > > > > > > > > > > > > > Hi All, > > > > > > > > > > > > > > I have created KIP-956 for defining read and write quota for > > tiered > > > > > > > storage. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-956+Tiered+Storage+Quotas > > > > > > > > > > > > > > Feedback and suggestions are welcome. > > > > > > > > > > > > > > Regards, > > > > > > > Abhijeet. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > Abhijeet. > > > > > > > > > > > > > -- > > Abhijeet. > > > -- Abhijeet.