tencent cloud



Last updated: 2024-01-03 14:27:38

    Scheduled Message

    After a message is sent to the server, the business may want the consumer to receive it at a later time point rather than immediately. This type of message is called "scheduled message".

    Subscription Type

    A subscription type (subscriptionType) is a type of topic subscription by a consumer. You can specify multiple subscription types, such as exclusive, failover, and shared.

    Subscription Name

    A subscription name (subscriptionName) uniquely identifies a group of subscribers.

    Partition Index

    A partition index (partionindex) denotes the number of a partition in a topic.

    Shared Type

    The shared type is a subscription type where a subscriber group can have multiple concurrent active consumer connections, and a message consumed by one of the consumers will not be consumed again by other consumers.


    In TSF, a namespace is an abstract collection of resources and objects. It isolates resources in the same cluster, so you can use the same account to create different environments. A cluster can have multiple namespaces, but a resource in the cluster can belong to only one namespace. With namespaces, you can divide a cluster into the development environment, test environment, etc. If there are active network connections, services in the same namespace can discover and call each other.
    In TCR, a namespace is a directory hierarchy in an instance like an organization in Docker Hub or a project in Harbor, which can be used to isolate image repositories of different projects, teams, or other organizations. A namespace falls between an instance and a repository, and its access level attribute directly determines the public or private attribute of image repositories in it. Image repositories and Helm chart repositories can share a namespace.
    In TDMQ, a namespace manages associated topics as a group. It is the basic unit of topic management. Each tenant can have multiple namespaces which correspond to different Tencent Cloud environments.

    Exclusive Type

    The exclusive type is a subscription type where a subscriber group can have only one active consumer.

    Batch ID

    A batch ID (batchid) denotes the number of a message in a batch of messages.


    A producer refers to a role that sends messages.


    See TDMQ.


    An entry is an element of a ledger, and a ledger is composed of a set of entries.


    A consumer refers to a role that receives messages.

    Message ID

    A message ID is the unique identifier of a message, which consists of four parts: ledgerid, entryid, partionindex, and batchid. Each message will receive a message ID assigned by the Tencent Cloud system, which can be returned to you through the SendMessage API request.

    Message Retention Period

    The message retention period refers to the retention period of a message that has been acknowledged by the consumer.


    Tencent Distributed Message Queue (TDMQ) for Pulsar is a proprietary finance-grade distributed message middleware developed based on Pulsar, a top open-source project of Apache. It features high cross-region consistency, reliability, and concurrency. Currently, it is widely used in Tencent's most billing scenarios, including primary payment process as well as real-time reconciliation, monitoring, and big data analysis.

    Message Expiry Time

    Message expiry time refers to the time to live (TTL) of an unacknowledged message.

    Message Type

    A message type is used to identify the type of a topic. Two topic types are supported: persistent and non-persistent. A persistent topic will return an ack for successful delivery after the message is stored to the disk.

    Delayed Message

    After a message is sent to the server, the business may want the consumer to receive it after a period of time rather than immediately. This type of message is called "delayed message".

    Failover Type

    The failover type is a subscription type where subscribers can exist in a primary/secondary relationship. The primary consumer consumes messages under normal conditions, and consumption will be switched to the secondary consumer when the primary consumer fails.


    A ledger is an element in a topic, and a topic is composed of a set of ledgers.


    In Oceanus, a topic is the smallest unit of stream connection to subscription and publishing. You can use a topic to denote a type of streaming data, just like a table in a database.
    In IoT Hub, a topic refers to a message communication topic, acting as the communication intermediary of the messages in the Pub/Sub pattern. It is required when publishing and subscribing to messages, and the communication is made based on the specific topic of each device.
    In TDMQ, CKafka, and CMQ, a topic refers to a collection of messages of a particular type. It is a logical concept used to store messages. Topics must be unique in a namespace.
    In CLS, a topic refers to the basic management unit provided by CLS. A log topic corresponds to an application or service and is the smallest management unit in CLS, around which collection, indexing, and delivery are configured. A logset can contain multiple log topics.
    In BI, a topic is a way to batch modify the styles of the overall components in order to make the report design more uniform. In BI systems, topics are often used for unified settings of chart components and page backgrounds.


    A tenant corresponds to an APPID in Tencent Cloud.
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