Motivation

In the org.apache.pulsar.metadata.impl.ZKMetadataStore class, during initialization and upon receiving the SessionReestablished event from ZooKeeper, a watcher is registered using the following code:

zkc.addWatch("/", this::handleWatchEvent, AddWatchMode.PERSISTENT_RECURSIVE,
        (rc, path, ctx) -> {
            // ...
}, null);

The use of this::handleWatchEvent here causes the watcher passed to the addWatch method not to be the same object each time, which may lead to duplicate registrations.

Modifications

Use the same watcher object when calling the addWatch method

Verifying this change

• Make sure that the change passes the CI checks.

• Added test in org.apache.pulsar.metadata.ZKSessionTest#testNoDuplicateWatcherRegistrationAfterSessionReestablished

Does this pull request potentially affect one of the following parts:

If the box was checked, please highlight the changes

• Dependencies (add or upgrade a dependency)
• The public API
• The schema
• The default values of configurations
• The threading model
• The binary protocol
• The REST endpoints
• The admin CLI options
• The metrics
• Anything that affects deployment

Documentation

• doc
• doc-required
• doc-not-needed
• doc-complete

Matching PR in forked repository

PR in forked repository: hrzzzz#16