Controller triggers rebalance pipeline after disconnect to catch missed events

[GrantPSpencer]

Issues

• My PR addresses the following Helix issues and references them in the PR description:
  Controller missing events due to disconnect #3005

Description

• Here are some details about my PR, including screenshots of any UI changes:
  Please see Controller missing events due to disconnect #3005 for more information on possible missed event bug. This PR adds a test case to capture the bug and a possible solution where the the manager triggers an onDemand rebalance if it is the lead controller. I'm not certain this is the best approach, but my progress on this has stalled and I figured I should open this issue up to open source discussion

Tests

• The following tests are written for this issue:

TestMissedEventAfterReconnect

• The following is the result of the "mvn test" command on the appropriate module:

mvn test -o -Dtest=TestMissedEventAfterReconnect -pl=helix-core


[INFO] -------------------------------------------------------
[INFO]  T E S T S
[INFO] -------------------------------------------------------
[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  54.036 s
[INFO] Finished at: 2025-02-13T12:06:32-08:00
[INFO] ------------------------------------------------------------------------

Changes that Break Backward Compatibility (Optional)

• My PR contains changes that break backward compatibility or previous assumptions for certain methods or API. They include:

N/A

Commits

• My commits all reference appropriate Apache Helix GitHub issues in their subject lines. In addition, my commits follow the guidelines from "How to write a good git commit message":
  1. Subject is separated from body by a blank line
  2. Subject is limited to 50 characters (not including Jira issue reference)
  3. Subject does not end with a period
  4. Subject uses the imperative mood ("add", not "adding")
  5. Body wraps at 72 characters
  6. Body explains "what" and "why", not "how"

Code Quality

• My diff has been formatted using helix-style.xml
  (helix-style-intellij.xml if IntelliJ IDE is used)

[junkaixue]

This is not a proper handling. If you need the full refresh, you can clean up the cache and let pipeline to read data. This will trigger another full refresh after pipeline running.