Pipeline Optimisation : Optimising getPath Method

[ngngwr]

Issues

• My PR addresses the following Helix issues and references them in the PR description:

Helix is facing increased pipeline execution time for very large clusters. Here we are trying to optimise the segments which are taking lot of time.

Description

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• getPath() is being called multiple times during the pipeline execution and not very efficient due to regex matching.

1. How it works before this change?

• Every time a ZooKeeper path needs to be built:
• Template string is retrieved: "/{clusterName}/INSTANCES/{instanceName}/CURRENTSTATES/{sessionId}"
• Regex pattern matcher is created to find all placeholders (e.g., {clusterName}, {instanceName})
• String scanning: Matcher scans the entire template string multiple times to locate each {...} placeholder
• String replacement: Each placeholder is replaced using String.replace(), creating new intermediate string objects
• This process repeats for every single path built during execution

2. How it will work after this change?

• One-time initialization (at application startup):
• Each template is parsed once into a PathTemplate object
• Static text parts are extracted and stored: ["/", "/INSTANCES/", "/CURRENTSTATES/", ""]
• No regex needed after this point
• Runtime path building (hot path):
• Uses StringBuilder to concatenate pre-parsed static parts with parameters
• Example: "/" + clusterName + "/INSTANCES/" + instanceName + "/CURRENTSTATES/" + sessionId
• Simple, fast string appending with no regex or searching

The above optimisation makes a difference when the cluster size is huge.

Tests

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Unit tested.

Changes that Break Backward Compatibility (Optional)

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None.

Documentation (Optional)

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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":
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  6. Body explains "what" and "why", not "how"

Code Quality

• My diff has been formatted using helix-style.xml
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[laxman-ch]

@ngngwr : Can we please get some evidence (detailed CPU profile) to prove if this really is a bottleneck.

[proud-parselmouth]

I think Grant already optimized PropertyPathKey, can you check this PR once?
apache#3040