Status

Current state: Accepted

Under Discussion thread: here

Discussion Voting thread: here

JIRA: KAFKA-15445

Please keep the discussion on the mailing list rather than commenting on the wiki (wiki discussions get unwieldy fast).

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1. Docker Image Size: Adding the jsa files will increase the size of the Docker image. Classes stored in the CDS are a few times (e.g., 2 – 5x) larger than classes stored in JAR files
2. Choosing Application Usage for JSA: For our POC, we focused on Kafka startup using default configurations. It's crucial to decide how broadly the application should be used to generate jsa files.
3. Startup Memory Footprint: While we did observe a reduction in startup memory footprint, we believe this difference may not significantly scale with production load.
4. CDS Archive Exclusions: The CDS archive doesn't include pre-JDK 6 classes, which are present in our codebase.
5. Limitations of CDS:
   1. The OpenJDK version used for building the jsa files and during runtime must be the same. If they are not, application wont fail but the expected optimisation won't be achieved.
   2. If a custom JAR is provided by the user, it's currently prepended to the existing classpath. However, CDS requires that the classpath used during jsa file generation should either be the same or a prefix of the classpath used during runtime. Otherwise, it will be disabled, and the expected optimisation won't be achieved.

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