Parameter | Required or Not | Description |
Name | Yes | Fill in the Topic name. The name must comply with the naming rule: it can only contain letters, digits, underscores, "-", and ".". It does not support names starting with "double underscores". The Topic name cannot be changed once created successfully. |
Remarks | No | Fill in the Topic description, no more than 64 characters. |
Number of Partitions | Yes | The concept of a physical partition. A Topic can contain one or more partitions. CKafka uses partitions as the allocation unit. The default deployment architecture requires at least 3 nodes. It is advisable to start with 3 partitions for more balanced data distribution. For partition configuration, refer to the Parameter Configuration Instructions. |
Number of Replicas | Yes | The number of replicas in a Partition is used to ensure high availability of the Partition. To ensure data reliability, 2 replicas are enabled by default. The number of replicas is also counted as the number of partitions. For example, if a customer creates a Topic with 6 partitions and 2 replicas, the total Partition limit used is 1 × 6 × 2 = 12. Note: Warning: Setting to single replica can cause availability issues. Proceed with caution. |
Tag | No | Tags are used to categorize and manage resources from different dimensions. For more details about tags, see Tag Management. |
retention.ms | Yes | The message retention period at the Topic level defaults to 3 days, with a range of 1 minute to 90 days. Messages will be deleted to preserve sufficient disk space once the retention duration is exceeded. |
Parameter Name | Default Value | Description |
Message Timestamp Type | LogAppendTime (Recommended) | Define the timestamp type in messages: CreateTime: The time when the producer created this message. Since the client time may deviate from server time, you need to check whether the written time is correct. LogAppendTime: The time when the server-side Broker receives the message. |
Preset ACL policy | Disable | Once enabled, you can select the preconfigured ACL policy in the dropdown list. For details, see Configuring ACL Policies. |
cleanup.policy | delete | Topic log cleanup policy: delete: Logs are deleted based on retention time. Messages are stored according to the configured message retention period. Old data is automatically cleaned up in case of insufficient disk capacity to ensure service availability. Suitable for normal message queue scenarios. compact: Logs are compressed by Key to ensure only the latest Value is kept for identical keys. Suitable for recovery status after system downtime and reloading cache after system restart. For example, when using Kafka Connect or Confluent Schema Registry, require the use of Kafka compact Topic to store system status or configuration messages. delete.compact: Combined policies, compress keys to retain the latest value, then delete expired data. Suitable for hybrid data such as social message flow. |
min.insync.replicas | 1 | Specify the minimum number of in-sync replicas (ISR) that must successfully receive messages sent by the producer. The value ranges between 1 and the maximum number of replicas for the Topic. A higher value improves data security (tolerating more node faults) but reduces availability (service becomes unwritable when ISR is not sufficient). When the producer sets request.required.acks to 1, min.insync.replicas specifies the minimum number of replicas. |
unclean.leader.election.enable | true | Whether to allow electing a new Leader from Out-of-Sync Replicas (OSR). true (default): Allow electing a Leader from OSR, giving priority to availability. false: Only allow electing a Leader from In-Sync Replicas (ISR), giving priority to data consistency. |
segment.ms | - | Segment fragment scrolling duration, ranging from 1 to 90 days, with a minimum unit of ms. |
retention.bytes | Defaults to the instance's message retention size | Message retention size by partition, ranging from 1 to 1024 GB. Number of partitions * retention.bytes = message retention size of the current Topic. For a Topic, if both message retention period and message retention size are set, the actual message retention will follow whichever threshold is reached first. (This parameter cannot be configured for Serverless instances.) |
max.message.bytes | - | The upper limit for a single message is 1KB to 12MB. When sending data, the client aggregates data sent to the same partition into batches. The server compares the size of each batch. |
Parameter | Default Value |
Number of Partitions | Enable automatic Topic creation with a default of at least 3 nodes. |
Number of Replicas | Enable automatic Topic creation with a default of 2 replicas. |
Default message retention time | Default is 3 days. The default value can be modified by setting the Topic global attribute. For specific operations, refer to Configure Topic Global Attribute. |
Default max message size | Default is 8 MB. The default value can be modified by setting the Topic global attribute. For specific operations, refer to Configure Topic Global Attribute. |
UncleanLeaderElectionEnable | Set to true by default to control whether to allow unsynchronized replicas to be selected as Leader. The default value can be modified by setting the Topic global attribute. For specific operations, refer to Configure Topic Global Attribute. |
Message Timestamp Type | Defaults to LogAppendTime, representing the time when the server-side Broker receives the message. |
cleanup.policy | Defaults to delete. Logs are deleted based on retention time. |
min.insync.replicas | Defaults to 1, used to specify the minimum number of synced replicas (ISR) that must successfully write messages sent by the producer. |
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