If nothing is set to event time, the value is 0. For example, applications attach a timestamp on when the message is processed. The timestamp is automatically applied by the producer.Īn optional timestamp attached to a message by applications. The timestamp of when the message is published. Message ID indicates a message's specific position in a ledger and is unique within a Pulsar cluster. The message ID of a message is assigned by bookies as soon as the message is persistently stored. If brokerDeduplicationEnabled is set to true, the sequence ID of each message is unique within a producer of a topic (non-partitioned) or a partition. Sequence ID can be used for message deduplication. The sequence ID of a message is initially assigned by its producer, indicating its order in that sequence, and can also be customized. The version number of the schema that the message is produced with.Įach Pulsar message belongs to an ordered sequence on its topic. The name of the topic that the message is published to. If you do not specify a producer name, the default name is used. The name of the producer who produces the message. Messages are optionally tagged with keys, which is useful for features like topic compaction.Īn optional key/value map of user-defined properties. It is a short name of message key or partition key. All Pulsar messages contain raw bytes, although message data can also conform to data schemas. The following table lists the components of messages. If the consumption of a message fails and you want this message to be consumed again, you can enable the message redelivery mechanism to request the broker to resend this message.
The retained messages are discarded only when a consumer acknowledges that all these messages are processed successfully. When a subscription is created, Pulsar retains all messages, even if the consumer is disconnected. In this pattern, producers publish messages to topics consumers subscribe to those topics, process incoming messages, and send acknowledgments to the broker when processing is finished. Pulsar is built on the publish-subscribe pattern (often abbreviated to pub-sub).
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