THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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CreateTopic Request (Version: 0) => [create_topic_requests] timeout create_topic_requests => topic partitions replication_factor [replica_assignment] [configs] topic => STRING partitions => INT32 replication_factor => INT32 replica_assignment => partition_id [replicas] partition_id => INT32 replicas => INT32 configs => config_key config_value config_key => STRING config_value => STRING timeout => INT32 |
CreateTopicRequest
is a batch request to initiate topic creation with either predefined or automatic replica assignment and optionally topic configuration.
Request semantics:
- Must be sent to the controller broker
- Multiple instructions for the same topic in one request will be silently ignored, only the last from the list will be executed.
- This is because the list of topics is modeled server side as a map with TopicName as the key
- The principle must be authorized to the "Create" Operation on the "Cluster" resource to create topics.
- Unauthorized requests will receive a ClusterAuthorizationException
Only one from
ReplicaAssignment or (
can be defined in one instruction. If both parameters are specified -Partitions
+ReplicationFactor
),ReplicaAssignment
takes precedence.- In the case
ReplicaAssignment
is defined number of partitions and replicas will be calculated from the suppliedReplicaAssignment
. - In the case of defined (
Partitions
+ReplicationFactor
) replica assignment will be automatically generated by the server. - One or the other must be defined. The existing broker side auto create defaults will not be used (default.replication.factor, num.partitions). The client implementation can have defaults for these options when generating the messages.
- The first replica in [replicas] is assumed to be the preferred leader. This matches current behavior elsewhere.
- In the case
- Setting a timeout > 0 will allow the request to block until the topic metadata is "complete" on the controller node.
- Complete means the local topic metadata has cache been completely populated (leaders, replicas, ISRs)and all partitions have leaders
- The topic metadata is updated when the controller sends out update metadata requests to the brokers
- If a timeout error occurs, the topic could still be created successfully at a later time. Its up to the client to query for the state at that point.
- Complete means the local topic metadata has cache been completely populated (leaders, replicas, ISRs)and all partitions have leaders
- The request is not transactional.
- If an error occurs on one topic, the other could still be created.
- Errors are reported independently.
QA:
- Why is CreateTopicRequest a batch request?
- Scenarios where tools or admins want to create many topics should be able to with fewer requests
- Example: MirrorMaker may want to create the topics downstream
- What happens if some topics error immediately? Will it return immediately?
- The request will block until all topics have either been created, errors, or the timeout has been hit
- There is no "short circuiting" where 1 error stops the other topics from being created
- Why implement "partial blocking" instead of fully async of fully consistent?
- See Cluster Consistent Blocking below
- Why require the request to go to the controller?
- The controller is responsible for the cluster metadata and its propogation
- See Request Forwarding below
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