Hi Abhijeet,
Thanks for the update and the explanation.
I had another look, and it LGTM now!
Thanks.
Luke
On Tue, Mar 5, 2024 at 2:50 AM Jun Rao <j...@confluent.io.invalid> wrote:
> Hi, Abhijeet,
>
> Thanks for the reply. Sounds good to me.
>
> Jun
>
>
> On Sat, Mar 2, 2024 at 7:40 PM Abhijeet Kumar <abhijeet.cse....@gmail.com>
> wrote:
>
> > Hi Jun,
> >
> > Thanks for pointing it out. It makes sense to me. We can have the
> following
> > metrics instead. What do you think?
> >
> > - remote-(fetch|copy)-throttle-time-avg (The average time in ms remote
> > fetches/copies was throttled by a broker)
> > - remote-(fetch|copy)-throttle-time--max (The maximum time in ms
> remote
> > fetches/copies was throttled by a broker)
> >
> > These are similar to fetch-throttle-time-avg and fetch-throttle-time-max
> > metrics we have for Kafak Consumers?
> > The Avg and Max are computed over the (sliding) window as defined by the
> > configuration metrics.sample.window.ms on the server.
> >
> > (Also, I will update the config and metric names to be consistent)
> >
> > Regards.
> >
> > On Thu, Feb 29, 2024 at 2:51 AM Jun Rao <j...@confluent.io.invalid>
> wrote:
> >
> > > Hi, Abhijeet,
> > >
> > > Thanks for the reply.
> > >
> > > The issue with recording the throttle time as a gauge is that it's
> > > transient. If the metric is not read immediately, the recorded value
> > could
> > > be reset to 0. The admin won't realize that throttling has happened.
> > >
> > > For client quotas, the throttle time is tracked as the average
> > > throttle-time per user/client-id. This makes the metric less transient.
> > >
> > > Also, the configs use read/write whereas the metrics use fetch/copy.
> > Could
> > > we make them consistent?
> > >
> > > Jun
> > >
> > > On Wed, Feb 28, 2024 at 6:49 AM Abhijeet Kumar <
> > abhijeet.cse....@gmail.com
> > > >
> > > wrote:
> > >
> > > > 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.
> > > >
> > >
> >
> >
> > --
> > Abhijeet.
> >
>
