Subscriptions in Pulsar
Subscriptions in Pulsar describe which consumers are consuming data from a topic and how they want to consume that data.
Subscriptions are managed in the broker as a collection of metadata about a topic and its subscribed consumers. This metadata includes:
Topic name - which topic the consumer wants data from
Subscription name - a string representing a qualified name for the subscription
Subscription type - which type of subscription is being used
Subscription cursor - a representation of the consumer’s current place in the subscribed topic log
For example, the Pulsar consumer below has a shared subscription starting at the earliest cursor position in
pulsarConsumer = pulsarClient.newConsumer(Schema.BYTES) .topic("my-topic") .subscriptionName("my-subscription") .subscriptionType(SubscriptionType.Shared) .subscriptionInitialPosition(SubscriptionInitialPosition.Earliest) .subscribe();
Read on to use Pulsar’s four types of subscriptions to manage your topic consumption.