Integration / Apache Pulsar Interview questions

What is message retention in Pulsar?

Retention determines how long already-acknowledged messages are kept in BookKeeper after every subscription has consumed them, since by default Pulsar deletes data once no subscription needs it anymore.

Configuring a retention policy (size- and/or time-based) at the namespace or topic level keeps messages around even after acknowledgment, useful for replaying history or onboarding a new subscription that needs to read from an earlier point.

This differs from a backlog quota, which limits how much unacknowledged data can accumulate for slow or stalled consumers - retention protects already-read data, backlog quota protects against unread data growing unbounded.

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By default, once every subscription acknowledges a message, Pulsar will: delete it, unless retention is configured

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keep it forever automatically

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move it to tiered storage automatically

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Retention differs from backlog quota because retention governs: already-acknowledged data

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unacknowledged backlog growth

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producer authentication

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Explain about Apache Pulsar. What is AppDynamics? What is Apache Pulsar? What is a Pulsar broker? What is Application Performance Monitoring (APM)? What is Apache BookKeeper? What are the core components of the AppDynamics platform? What is the Controller in AppDynamics? What are tenants and namespaces in Pulsar? What is a topic in Pulsar? What is an App Agent in AppDynamics? What is a producer in Pulsar? What are the types of agents available in AppDynamics? What is a consumer in Pulsar? What is a Business Transaction in AppDynamics? What is a Tier in AppDynamics? What is a subscription in Pulsar? Define a partitioned topic in Pulsar? What is a Node in AppDynamics? What is a Business Application in AppDynamics? What is Pulsar's metadata store used for? What is the Application Flow Map? What are Pulsar Functions? What is Pulsar IO? What is a Health Rule? What is a Policy in AppDynamics? Describe geo-replication in Pulsar? What is a Transaction Snapshot? What is tiered storage in Pulsar? What is a non-persistent topic in Pulsar? Define baseline in AppDynamics? What is the Machine Agent used for? What are the subscription types in Pulsar? What is End User Monitoring (EUM)? What is message retention in Pulsar? What is schema registry in Pulsar? What is Database Visibility in AppDynamics? What are Backends in AppDynamics? List the core components of a Pulsar cluster? How do you create a topic in Pulsar? Describe the Metric Browser in AppDynamics? What is the difference between a Tier and a Node in AppDynamics? What is the difference between Pulsar and Kafka's storage architecture? How does Pulsar separate compute and storage? How does AppDynamics automatically discover Business Transactions? What is the difference between automatic and custom Business Transaction match rules? Why is Pulsar considered multi-tenant by design? What is the difference between Shared and Exclusive subscriptions? 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