>Should this be "positions"? We are going to split one bundle into
multi-bundles,
in most cases, bundle number will be position number + 1, right?
Sure, it should be “positions” or “positionList”
PengHui Li <peng...@apache.org> 于2022年2月21日周一 20:50写道：
> > And the (anti-)affinity way needs more discussion or maybe we can
> introduce
> a new PIP for it.
>
> +1
>
> Thanks,
> Penghui
>
> On Mon, Feb 21, 2022 at 6:47 PM Haiting Jiang <jianghait...@apache.org>
> wrote:
>
> > > 2. calculate the position to split this bundle(also need a new API)
> > Should this be "positions"? We are going to split one bundle into
> > multi-bundles,
> > in most cases, bundle number will be position number + 1, right?
> >
> > > And the (anti-)affinity way needs more discussion or maybe we can
> > introduce
> > > a new PIP for it.
> > +1, this is not in the scope of this PIP.
> >
> >
> > Thanks,
> > Haiting
> >
> > On 2022/02/21 08:57:01 Aloys Zhang wrote:
> > > Hi penghui and haiting,
> > >
> > > I try to figure out how the (anti-)affinity works.
> > >
> > > > if I understand correctly, it looks like if we have a partitioned
> topic
> > > with 10
> > > > partitions under a namespace with 16 bundles, if applies the
> > > anti-affinity policy,
> > > > partition-0 map to bundle 0, partition-1 map to bundle 1, and so on.
> > > > Of course, it is not necessary for every partitioned topic to start
> > from
> > > bundle 0,
> > > > we can use the partition-0 hash to determine the start bundle index.
> > >
> > > As penghui described, I think this is a mechanism for assigning topics
> > to a
> > > bundle that controls how a topic is mapped to a bundle.
> > >
> > > > IMO, this affinity serves the purpose of isolating an abnormal topic
> to
> > > some spare
> > > > brokers. These brokers host these kind of topics only. Here are some
> > > cases :
> > >
> > > And as haiting mentioned here, It's more like an isolation policy that
> > > decides topics can be owned by which broker.
> > > So, I am a little confused about how the (anti-)affinity works now.
> > >
> > > Back to this PIP which aims to solve the problem that a small number of
> > > topics in a bundle have a load that exceeds the average.
> > > So, we can
> > > 1. get the positions for the topics with we are interested( need a new
> > API)
> > > 2. calculate the position to split this bundle(also need a new API)
> > > I think this way is enough for solving the problem.
> > >
> > > And the (anti-)affinity way needs more discussion or maybe we can
> > introduce
> > > a new PIP for it.
> > > What do you think?@penghui @haiting
> > >
> > >
> > > Thanks,
> > > Aloys
> > >
> > > Aloys Zhang <aloyszh...@apache.org> 于2022年2月21日周一 14:39写道：
> > >
> > > > Hi, penghui
> > > >
> > > > > The new API does not necessarily have to query by topic one by
> one,
> > > > we have listed all the "topic -> position" of a bundle?
> > > >
> > > > I see. After we got all the positions of the topics we want to split
> > in a
> > > > bundle, it's quite easy for us to decide how to it.
> > > >
> > > > Haiting Jiang <jianghait...@apache.org> 于2022年2月20日周日 12:05写道：
> > > >
> > > >> > Do you have an example for affinity? I don't fully understand how
> > this
> > > >> is
> > > >> > used
> > > >> > in practice.
> > > >>
> > > >> IMO, this affinity serves the purpose of isolating an abnormal topic
> > to
> > > >> some spare
> > > >> brokers. These brokers host these kind of topics only. Here are
> some
> > > >> cases :
> > > >>
> > > >> 1. A topic may have unexpected short spike traffic flows
> periodically
> > and
> > > >> causing broker overloads and negative impact on other topics.
> > > >> Until we have more proper solutions, we can always isolate these
> > topics
> > > >> first,
> > > >> and make the service recover time as small as possible.
> > > >>
> > > >> 2. Some users may encounter some bugs in brokers, and we can isolate
> > the
> > > >> topic to
> > > >> exclusive brokers, and use more radical approach to locate the bug,
> > like
> > > >> enable debug
> > > >> level logs or even add some temporary code patch.
> > > >>
> > > >> 3. User may already have configured failure domain and anti-affinity
> > > >> namespace, but with
> > > >> business logic code changes, some topic may need to migrate from one
> > > >> namespace
> > > >> to another. This will take some time for user to change the client
> > side
> > > >> config.
> > > >> In the meanwhile, we can isolate the topic first.
> > > >>
> > > >> Thanks,
> > > >> Haiting
> > > >>
> > > >> On 2022/02/18 15:26:09 PengHui Li wrote:
> > > >> > Hi Haiting,
> > > >> >
> > > >> > > I think this approach have more potential with abnormal topic
> > > >> isolation.
> > > >> > If we can introduce
> > > >> > some kind of bundle isolation strategy, (like broker-bundle
> > affinity and
> > > >> > anti-affinity mechanism), we can easily isolate some unexpected
> > traffic
> > > >> to
> > > >> > some empty brokers.
> > > >> > IMO, this would improve the stability of broker cluster.
> > > >> >
> > > >> > if I understand correctly, it looks like if we have a partitioned
> > topic
> > > >> > with 10
> > > >> > partitions under a namespace with 16 bundles, if applies the
> > > >> anti-affinity
> > > >> > policy,
> > > >> > partition-0 map to bundle 0, partition-1 map to bundle 1, and so
> on.
> > > >> > Of course, it is not necessary for every partitioned topic to
> start
> > from
> > > >> > bundle 0,
> > > >> > we can use the partition-0 hash to determine the start bundle
> index.
> > > >> >
> > > >> > Do you have an example for affinity? I don't fully understand how
> > this
> > > >> is
> > > >> > used
> > > >> > in practice.
> > > >> >
> > > >> > Best,
> > > >> > Penghui
> > > >> >
> > > >> > On Fri, Feb 18, 2022 at 11:16 PM PengHui Li <peng...@apache.org>
> > wrote:
> > > >> >
> > > >> > > Hi Aloys,
> > > >> > >
> > > >> > > > Do you mean that
> > > >> > > 1. First, add a new API, maybe `getHashPositioin`, to get the
> > hash
> > > >> > > position in a bundle
> > > >> > > 2. Then use this position to split the overloaded bundle
> > > >> > > If so, when we split a bundle with multi partitions of a topic,
> we
> > > >> need to
> > > >> > > call the `getHashPositioin` multi times to get the middle
> > position of
> > > >> all
> > > >> > > these positions.
> > > >> > >
> > > >> > > Yes, this want I mean. In this way, users can control to assign
> 1
> > > >> topic or
> > > >> > > 3 topics to one bundle. This is more like increasing the
> > transparency
> > > >> of
> > > >> > > the topic in the bundle, you can all the positions of the
> topics,
> > so
> > > >> how
> > > >> > > planning for bundle splitting becomes more flexible.
> > > >> > >
> > > >> > > The new API does not necessarily have to query by topic one by
> > one,
> > > >> > > we have listed all the "topic -> position" of a bundle?
> > > >> > >
> > > >> > > Thanks,
> > > >> > > Penghui
> > > >> > >
> > > >> > > On Fri, Feb 18, 2022 at 4:51 PM Haiting Jiang <
> > > >> jianghait...@apache.org>
> > > >> > > wrote:
> > > >> > >
> > > >> > >> Hi Aloys,
> > > >> > >> +1 for this great PIP.
> > > >> > >>
> > > >> > >> > The Admin CLI `bin/pulsar-admin namespaces split-bundle -b
> > > >> > >> ${bundle_range}`
> > > >> > >> > will add a new parameter "--topic" or "-t" for `outstanding
> > topic`
> > > >> > >> name.
> > > >> > >>
> > > >> > >> Do we have limitation on this "topic" parameter. Can this be a
> > > >> > >> partitioned topic?
> > > >> > >> If so, will this new algorithm split the bundle into more than
> 2
> > > >> bundles?
> > > >> > >> like each bundle for
> > > >> > >> one partition.
> > > >> > >>
> > > >> > >> > This algorithm has a disadvantage, it can only deal
> > > >> > >> > with one `outstanding topic`.
> > > >> > >>
> > > >> > >> For this disadvantage, I think it can be solved by extends the
> > > >> "topic"
> > > >> > >> parameter from one topic to a topic list.
> > > >> > >>
> > > >> > >> > The other algorithm is to split the bundle at the hashcode
> > point
> > > >> of the
> > > >> > >> > `outstanding partition` which will split the bundle into
> three
> > > >> bundles
> > > >> > >> once
> > > >> > >> > a time. The middle one contains the only point the hashcode
> of
> > the
> > > >> > >> > `outstanding partition, the left one is less than the
> > hashcode, the
> > > >> > >> right
> > > >> > >> > one is more than the hashcode.
> > > >> > >> > E.g. if we have a bundle 0x00_0x10 contains two `outstanding
> > > >> partition`
> > > >> > >> > (partition-x and partition-y) whose hashcode is 0x03 and
> 0x07,
> > this
> > > >> > >> > algorithm is going to split bundle the bundle into five new
> > > >> bundles,
> > > >> > >> > 0x00_0x03, 0x03_0x04( for parition-x), 0x04_0x07, 0x07_0x08(
> > for
> > > >> > >> > partition-y), 0x08_0x10.
> > > >> > >>
> > > >> > >> I think this approach have more potential with abnormal topic
> > > >> isolation.
> > > >> > >> If we can introduce
> > > >> > >> some kind of bundle isolation strategy, (like broker-bundle
> > affinity
> > > >> and
> > > >> > >> anti-affinity mechanism), we can easily isolate some unexpected
> > > >> traffic to
> > > >> > >> some empty brokers.
> > > >> > >> IMO, this would improve the stability of broker cluster.
> > > >> > >>
> > > >> > >> Thanks,
> > > >> > >> Haiting
> > > >> > >>
> > > >> > >> On 2022/02/17 15:47:15 Aloys Zhang wrote:
> > > >> > >> > Hi Pulsar Community,
> > > >> > >> >
> > > >> > >> > This is a PIP discussion on how to support split partitions
> > > >> belonging to
> > > >> > >> > specified topics in a bundle.
> > > >> > >> >
> > > >> > >> > The issue can be found:
> > > >> https://github.com/apache/pulsar/issues/13761
> > > >> > >> >
> > > >> > >> > I copy the content here for convenience, any suggestions are
> > > >> welcome and
> > > >> > >> > appreciated.
> > > >> > >> >
> > > >> > >> >
> > > >> > >> > ## Motivation
> > > >> > >> >
> > > >> > >> > As we all know, a namespace bundle may contain lots of
> > partitions
> > > >> > >> belonging
> > > >> > >> > to different topics.
> > > >> > >> > The throughput of these topics may vary greatly. Some topics
> > may
> > > >> with
> > > >> > >> very
> > > >> > >> > high rate/throughput while other topics have a very low
> > > >> rate/throughput.
> > > >> > >> >
> > > >> > >> > These partitions with high rate/throughput can cause broker
> > > >> overload and
> > > >> > >> > bundle unloading.
> > > >> > >> > At this point, if we split bundle manually with
> > > >> `range_equally_divide`
> > > >> > >> or
> > > >> > >> > `topic_count_equally_divide` split algorithm, there may need
> > many
> > > >> times
> > > >> > >> > split before these high rate/through partitions assigned to
> > > >> different
> > > >> > >> new
> > > >> > >> > bundles.
> > > >> > >> >
> > > >> > >> > For convenience, we call these high throughput topics
> > `outstanding
> > > >> > >> topic`
> > > >> > >> > and their partitions `outstanding partition` in this PIP.
> > > >> > >> >
> > > >> > >> > ## Goal
> > > >> > >> >
> > > >> > >> > Our goal is to make it easier to split `outstanding
> partition`
> > > >> into new
> > > >> > >> > bundles.
> > > >> > >> >
> > > >> > >> > There are two alternative ways to achieve this. Either of
> them
> > > >> will add
> > > >> > >> a
> > > >> > >> > new algorithm for bundle split. The difference is how the new
> > > >> bundle
> > > >> > >> split
> > > >> > >> > algorithm is implemented.
> > > >> > >> >
> > > >> > >> > One algorithm is to split bundle by `outstanding topic` which
> > will
> > > >> split
> > > >> > >> > the bundle into two new bundles and each new bundle contains
> an
> > > >> equally
> > > >> > >> > `outstanding partition` once a time.
> > > >> > >> > E.g, a bundle contains lots of topic partitions, and only one
> > > >> > >> `outstanding
> > > >> > >> > topic`(T) with 2 `outstanding partition` (T-partition-n,
> > > >> > >> Tpartition-n+1).
> > > >> > >> > This algorithm split this bundle at the middle point of these
> > two
> > > >> > >> > partition's hashcode. This algorithm has a disadvantage, it
> > can
> > > >> only
> > > >> > >> deal
> > > >> > >> > with one `outstanding topic`.
> > > >> > >> >
> > > >> > >> > So we raised up another algorithm.
> > > >> > >> >
> > > >> > >> > The other algorithm is to split the bundle at the hashcode
> > point
> > > >> of the
> > > >> > >> > `outstanding partition` which will split the bundle into
> three
> > > >> bundles
> > > >> > >> once
> > > >> > >> > a time. The middle one contains the only point the hashcode
> of
> > the
> > > >> > >> > `outstanding partition, the left one is less than the
> > hashcode, the
> > > >> > >> right
> > > >> > >> > one is more than the hashcode.
> > > >> > >> > E.g. if we have a bundle 0x00_0x10 contains two `outstanding
> > > >> partition`
> > > >> > >> > (partition-x and partition-y) whose hashcode is 0x03 and
> 0x07,
> > this
> > > >> > >> > algorithm is going to split bundle the bundle into five new
> > > >> bundles,
> > > >> > >> > 0x00_0x03, 0x03_0x04( for parition-x), 0x04_0x07, 0x07_0x08(
> > for
> > > >> > >> > partition-y), 0x08_0x10.
> > > >> > >> >
> > > >> > >> > ## API Changes
> > > >> > >> >
> > > >> > >> > The Admin CLI `bin/pulsar-admin namespaces split-bundle -b
> > > >> > >> ${bundle_range}`
> > > >> > >> > will add a new parameter "--topic" or "-t" for `outstanding
> > topic`
> > > >> > >> name.
> > > >> > >> >
> > > >> > >> > The split interface changed from
> > > >> > >> >
> > > >> > >> > ```JAVA
> > > >> > >> > void splitNamespaceBundle(String namespace, String bundle,
> > boolean
> > > >> > >> > unloadSplitBundles, String splitAlgorithmName)throws
> > > >> > >> PulsarAdminException;
> > > >> > >> > ```
> > > >> > >> >
> > > >> > >> > to
> > > >> > >> >
> > > >> > >> > ```java
> > > >> > >> > void splitNamespaceBundle(String namespace, String bundle,
> > boolean
> > > >> > >> > unloadSplitBundles,
> > > >> > >> > String splitAlgorithmName,
> String
> > > >> topic)
> > > >> > >> > throws PulsarAdminException;
> > > >> > >> > ```
> > > >> > >> >
> > > >> > >> > ## Implementation
> > > >> > >> >
> > > >> > >> > There are changes both from the Admin CLI and the broker
> side.
> > > >> > >> >
> > > >> > >> > First, Admin CLI for split bundle should support to specify
> the
> > > >> > >> > `outstanding topic`,
> > > >> > >> >
> > > >> > >> > ```java
> > > >> > >> > /**
> > > >> > >> > * Split namespace bundle.
> > > >> > >> > *
> > > >> > >> > * @param namespace
> > > >> > >> > * @param bundle range of bundle to split
> > > >> > >> > * @param unloadSplitBundles
> > > >> > >> > * @param splitAlgorithmName
> > > >> > >> > * @param topic
> > > >> > >> > * @throws PulsarAdminException
> > > >> > >> > */
> > > >> > >> > void splitNamespaceBundle(String namespace, String
> bundle,
> > > >> boolean
> > > >> > >> > unloadSplitBundles,
> > > >> > >> > String splitAlgorithmName,
> String
> > > >> topic)
> > > >> > >> > throws PulsarAdminException;
> > > >> > >> >
> > > >> > >> > ```
> > > >> > >> >
> > > >> > >> > ```java
> > > >> > >> > /**
> > > >> > >> > * Split namespace bundle asynchronously.
> > > >> > >> > *
> > > >> > >> > * @param namespace
> > > >> > >> > * @param bundle range of bundle to split
> > > >> > >> > * @param unloadSplitBundles
> > > >> > >> > * @param splitAlgorithmName
> > > >> > >> > */
> > > >> > >> > CompletableFuture<Void> splitNamespaceBundleAsync(
> > > >> > >> > String namespace, String bundle, boolean
> > > >> unloadSplitBundles,
> > > >> > >> > String splitAlgorithmName, String topic);
> > > >> > >> > ```
> > > >> > >> >
> > > >> > >> > And for the broker side, first encapsulates the parameters
> for
> > > >> bundle
> > > >> > >> split
> > > >> > >> > into a new class `BundleSplitOption`
> > > >> > >> >
> > > >> > >> > ```java
> > > >> > >> > public class BundleSplitOption {
> > > >> > >> > private NamespaceService service;
> > > >> > >> > private NamespaceBundle bundle;
> > > >> > >> > private String topic;
> > > >> > >> > }
> > > >> > >> > ```
> > > >> > >> >
> > > >> > >> > add a new split algorithm
> > > >> > >> >
> > > >> > >> > ```java
> > > >> > >> > ublic class
> > SpecifiedTopicCountEquallyDivideBundleSplitAlgorithm
> > > >> > >> implements
> > > >> > >> > NamespaceBundleSplitAlgorithm {
> > > >> > >> > @Override
> > > >> > >> > public CompletableFuture<List<Long>>
> > > >> > >> getSplitBoundary(BundleSplitOption
> > > >> > >> > bundleSplitOption) {
> > > >> > >> >
> > > >> > >> > });
> > > >> > >> > }
> > > >> > >> > }
> > > >> > >> > ```
> > > >> > >> >
> > > >> > >> > add the new algorithm to `NamespaceBundleSplitAlgorithm`
> > > >> > >> >
> > > >> > >> > ```JAVA
> > > >> > >> > String SPECIFIED_TOPIC_COUNT_EQUALLY_DIVIDE =
> > > >> > >> > "specified_topic_count_equally_divide";
> > > >> > >> >
> > > >> > >> > List<String> AVAILABLE_ALGORITHMS =
> > > >> > >> > Lists.newArrayList(RANGE_EQUALLY_DIVIDE_NAME,
> > > >> > >> > TOPIC_COUNT_EQUALLY_DIVIDE,
> > > >> > >> > SPECIFIED_TOPIC_COUNT_EQUALLY_DIVIDE);
> > > >> > >> >
> > > >> > >> > NamespaceBundleSplitAlgorithm
> > > >> > >> SPECIFIED_TOPIC_COUNT_EQUALLY_DIVIDE_ALGO =
> > > >> > >> > new
> > > >> SpecifiedTopicCountEquallyDivideBundleSplitAlgorithm();
> > > >> > >> > ```
> > > >> > >> >
> > > >> > >> > modify the `splitAndOwnBundle` and
> > `splitAndOwnBundleOnceAndRetry`
> > > >> for
> > > >> > >> > [[NamespaceService.java](
> > > >> > >> >
> > > >> > >>
> > > >>
> >
> https://github.com/apache/pulsar/pull/13796/files#diff-99867fd2e328e0a689daa8f60d174aa96d87dd0d0fd29b9e68fe2e1f377b55a1)](https://github.com/apache/pulsar/pull/13796/files#diff-99867fd2e328e0a689daa8f60d174aa96d87dd0d0fd29b9e68fe2e1f377b55a1
> > > >> > >> )
> > > >> > >> >
> > > >> > >> >
> > > >> > >> > ```java
> > > >> > >> > public CompletableFuture<Void>
> > splitAndOwnBundle(NamespaceBundle
> > > >> bundle,
> > > >> > >> > boolean unload,
> > > >> > >> >
> > > >> > >> > NamespaceBundleSplitAlgorithm splitAlgorithm, String topic)
> {
> > > >> > >> >
> > > >> > >> > final CompletableFuture<Void> unloadFuture = new
> > > >> > >> > CompletableFuture<>();
> > > >> > >> > final AtomicInteger counter = new
> > > >> > >> > AtomicInteger(BUNDLE_SPLIT_RETRY_LIMIT);
> > > >> > >> > splitAndOwnBundleOnceAndRetry(bundle, unload,
> counter,
> > > >> > >> > unloadFuture, splitAlgorithm, topic);
> > > >> > >> >
> > > >> > >> > return unloadFuture;
> > > >> > >> > }
> > > >> > >> > ```
> > > >> > >> >
> > > >> > >> > ```java
> > > >> > >> > void splitAndOwnBundleOnceAndRetry(NamespaceBundle bundle,
> > > >> > >> > boolean unload,
> > > >> > >> > AtomicInteger counter,
> > > >> > >> >
> CompletableFuture<Void>
> > > >> > >> > completionFuture,
> > > >> > >> >
> > > >> NamespaceBundleSplitAlgorithm
> > > >> > >> > splitAlgorithm,
> > > >> > >> > String topic) {
> > > >> > >> > ```
> > > >> > >> >
> > > >> > >> > Also, we change the REST api and broker.conf
> > > >> > >> >
> > > >> > >> > ```java
> > > >> > >> > public void splitNamespaceBundle(
> > > >> > >> > @Suspended final AsyncResponse asyncResponse,
> > > >> > >> > @PathParam("property") String property,
> > > >> > >> > @PathParam("cluster") String cluster,
> > > >> > >> > @PathParam("namespace") String namespace,
> > > >> > >> > @PathParam("bundle") String bundleRange,
> > > >> > >> > @QueryParam("authoritative")
> @DefaultValue("false")
> > > >> boolean
> > > >> > >> > authoritative,
> > > >> > >> > @QueryParam("unload") @DefaultValue("false")
> > boolean
> > > >> unload,
> > > >> > >> > @QueryParam("topic") @DefaultValue("") String
> > topic) {}
> > > >> > >> > ```
> > > >> > >> >
> > > >> > >> > ```shell
> > > >> > >> >
> > > >> > >>
> > > >>
> >
> supportedNamespaceBundleSplitAlgorithms=range_equally_divide,topic_count_equally_divide,specified_topic_count_equally_divide
> > > >> > >> > ```
> > > >> > >> >
> > > >> > >>
> > > >> > >
> > > >> >
> > > >>
> > > >
> > >
> >
>
