Key terms for SOFAStack Message Queue-Scalable Open Financial Architecture(SOFAStack)-阿里云帮助中心

This topic defines the key terms for SOFAStack Message Queue to help you better understand its concepts and use the service.

Chinese	English	Definition
Message topic	Topic	A topic is a primary message type used to categorize messages. For more information, see Topic and Tag.
Message	Message	The unit of information transmitted in Message Queue.
Message ID	Message ID	The globally unique identifier for a message. The Message Queue system automatically generates a message ID for each message.
Message Key	Message Key	The business identifier for a message. A producer sets the message key to uniquely identify a specific business logic.
Message tag	Tag	A message tag is a secondary message type. It is used to further categorize messages within a topic. For more information, see Topic and Tag.
Message producer	Producer	A producer, also known as a publisher, creates and sends messages.
Producer instance	Producer instance	An object instance of a producer. Different producer instances can run in different processes or on different machines. A producer instance is thread-safe and can be shared among multiple threads within the same process.
Message consumer	Consumer	A consumer, also known as a subscriber, receives and consumes messages.
Consumer instance	Consumer instance	An object instance of a consumer. Different consumer instances can run in different processes or on different machines. A thread pool is configured within a consumer instance to consume messages.
Group	Group	A group of producers or consumers that typically produce or consume the same type of message with consistent publishing or subscription logic.
Group ID	Group ID	The identifier for a Group.
Queue	Queue	Each topic contains one or more queues to store messages. The number of queues for each topic depends on the message type and the region where the instance is located. For the specific number of queues, contact technical support.
Clustering consumption	Clustering consumption	All consumers identified by a Group ID share the consumption of messages. For example, if a topic has 9 messages and a Group ID has 3 consumer instances, each instance consumes only 3 of the messages in clustering consumption mode. For more information, see Clustering and Broadcasting Consumption.
Broadcasting consumption	Broadcasting consumption	Each consumer identified by a Group ID consumes every message once. For example, if a topic has 9 messages and a Group ID has 3 consumer instances, each instance consumes all 9 messages in broadcasting consumption mode. For more information, see Clustering and Broadcasting Consumption.
Scheduled message	Scheduled message	A message sent by a producer that is not delivered immediately. Instead, it is delivered to a consumer at a specific time in the future. For more information, see Scheduled and Delayed Messages.
Delayed message	Delayed message	A message sent by a producer that is not delivered immediately. Instead, it is delivered to a consumer after a specified delay. For more information, see Scheduled and Delayed Messages.
Transactional message	Transactional message	Message Queue provides a distributed transaction feature similar to X/Open XA. Transactional messages help achieve eventual consistency in distributed transactions. For more information, see Transactional Messages.
Ordered message	Ordered message	A type of message that Message Queue publishes and consumes in a specific order. Ordered messages include globally ordered messages and partitionally ordered messages. Currently, only partitionally ordered messages are supported. For more information, see Ordered Messages.
Partition-ordered message	Partitionally ordered message	For a specific topic, all messages are partitioned based on a sharding key. Messages within the same partition are published and consumed in strict First-In, First-Out (FIFO) order. The sharding key is a critical field used in ordered messages to distinguish between different partitions. It is a completely different concept from the message key of a normal message. For more information, see Ordered Messages.
Message accumulation	Message accumulation	A situation where messages build up on the Message Queue server. This happens when producers send messages, but consumers have limited capacity and cannot process them right away.
Message filtering	Message filtering	A feature that lets consumers filter messages based on tags. This ensures that a consumer only receives messages of a specific type. Message filtering is performed on the server-side. For more information, see Message Filtering.
Message trace	Message trace	The complete path of a message, from the producer to the consumer. A message trace collects data such as timestamps and locations from all related nodes in the path. It lets you clearly track the entire journey of a message: from the producer, through the Message Queue server, to the consumer. This helps with troubleshooting. For more information, see Query Message Traces.
Consumer offset resetting	Reset consumption offset	The action of resetting a consumer's progress for a subscribed topic to a specific point in time. This must be within the message retention period (default: 3 days). After the reset, the consumer will receive messages that were sent by the producer to the Message Queue server after the specified time. For more information, see Reset a Consumer Offset.