The Apache Pulsar community releases version 2.9.2! 60 contributors provided improvements and bug fixes that delivered 317 commits.

Highlights of this release are as below:

• Transactions performance test tool is available. PR-11933

• Brokers decrease the number of unacked messages. PR-13383

• Readers continue to read data from the compacted ledgers. PR-13629

This blog walks through the most noteworthy changes grouped by the affected functionalities. For the complete list including all features, enhancements, and bug fixes, check out the Pulsar 2.9.2 Release Notes.

Readers continue to read data from the compacted ledgers. PR-13629

Issue

Previously, when topics were unloaded, some data was lost to be read by readers if they have consumed some messages from some compacted ledgers.

Resolution

Rewound the reader cursor to the next message of the mark delete position if readCompacted = true.

Brokers decrease the number of unacked messages. PR-13383

Issue

Previously, brokers did not decrease the number of unacked messages if batch ack was enabled. Consequently, consumers were blocked if they reached maxUnackedMessagesPerConsumer limit.

Resolution

Decreased the number of unacked messages when individualAckNormal was called.

Chunked messages can be queried through Pulsar SQL. PR-12720

Issue

Previously, chunked messages could not be queried through Pulsar SQL.

Resolution

Add a chunked message map in PulsarRecordCursor to maintain incomplete chunked messages. If one chunked message was received completely, it would be offered in the message queue to wait for deserialization.

Support enable or disable schema upload at the broker level. PR-12786

Issue

Previously, Pulsar didn't support enabling or disabling schema upload at the broker level.

Resolution

Added the configuration isSchemaAutoUploadEnabled on the broker side.

Readers can read the latest messages in compacted topics. PR-14449

Issue

Previously, readers were not able to read the latest messages in compacted topics if readers enabled readCompacted and all the data of topics has been compacted to compacted ledgers.

Resolution

Added the forceReset configuration for the managed cursor, so that the cursor could be reset to a given position and readers can read data from compacted ledgers.

Transaction sequenceId can be recovered correctly. PR-13209

Issue

Previously, the wrong transaction sequenceId was recovered due to incorrect managedLedger properties.

Resolution

Used ManagedLedgerInterceptor to update current sequenceId to managedLedger properties and more.

Transactions performance test tool is available. PR-11933

Issue

Previously, it was hard to test transaction performance (such as the delay and rate of sending and consuming messages) when opening a transaction.

Resolution

Added PerformanceTransaction class to support this enhancement.

Port exhaustion and connection issues no longer exist in Pulsar Proxy. PR-14078

Issue

Previously, Pulsar proxy would get into a state where it stopped proxying broker connections while Admin API proxying kept working.

Resolution

Optimized the proxy connection to fail-fast if the target broker was not active, added connect timeout handling to proxy connection, and more.

No race condition in OpSendMsgQueue when publishing messages. PR-14231

Issue

After the method getPendingQueueSize() was called and the send receipt came back, the peek from the pendingMessages might get NPE during the process.

Resolution

Added a thread-safe message count object in OpSendMsgQueue for each compute process.

Change ContextClassLoader to NarClassLoader in AdditionalServlet. PR-13501

Issue

Previously, if a class was dynamically loaded by NarClassLoader, ClassNotFoundException occurred when it was used by the default class load.

Resolution

Changed context class loader through Thread.currentThread().setContextClassLoader(classLoader) before every plugin calling back and changed the context class loader back to original class loader afterwards.

What’s Next?

If you are interested in learning more about Pulsar 2.9.2, you can download and try it out now!

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For more information about the Apache Pulsar project and current progress, visit the Pulsar website, follow the project on Twitter @apache_pulsar, and join Pulsar Slack!