[CC4] CNDB-15558: ULID-based SSTable ID generation can fail with an NPE

[michaelsembwever]

https://github.com/riptano/cndb/issues/15558

What is the issue

ULID-based SSTable ID generation can fail with an NPE when generating a new ID. The root cause is that the underlying ULID generator can generate an empty Optional when the clock is moved backwards to before the previously generated ID or in certain rare overflow conditions when timestamp collides. If it's our first time through the generation loop, we prematurely exit with a null newVal.

Top of the error stack:

java.lang.NullPointerException
	at org.apache.cassandra.utils.TimeUUID.approximateFromULID(TimeUUID.java:58)
	at org.apache.cassandra.io.sstable.ULIDBasedSSTableId.<init>(ULIDBasedSSTableId.java:52)
	at org.apache.cassandra.io.sstable.ULIDBasedSSTableId$Builder.lambda$generator$0(ULIDBasedSSTableId.java:129)

This can cause a flush to fail.

What does this PR fix and why was it fixed

Continue looping until newVal gets a value. The loop can spin until the corrected time catches up to the time of the most recently used ULID generation ID. This should be a short duration in a healthy cluster without large time corrections from sync.

[github-actions]

Checklist before you submit for review

• This PR adheres to the Definition of Done
• Make sure there is a PR in the CNDB project updating the Converged Cassandra version
• Use NoSpamLogger for log lines that may appear frequently in the logs
• Verify test results on Butler
• Test coverage for new/modified code is > 80%
• Proper code formatting
• Proper title for each commit staring with the project-issue number, like CNDB-1234
• Each commit has a meaningful description
• Each commit is not very long and contains related changes
• Renames, moves and reformatting are in distinct commits
• All new files should contain the DataStax copyright header instead of the Apache License one

[michaelsembwever]

running CI, and checking if there's a unit test to add here…

[jkni]

Thanks for the PR! Overall, LGTM and I appreciate the increased test coverage. I left a few minor nits inline. Can you run CNDB CI with a build of this PR?

[michaelsembwever]

cndb tests: https://github.com/riptano/cndb/pull/16340

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[cassci-bot]

❌ Build ds-cassandra-pr-gate/PR-2175 rejected by Butler

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3 regressions found
See build details here

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Found 3 new test failures

Test	Explanation	Runs	Upstream
o.a.c.db.commitlog.BatchCommitLogTest.testBatchCLSyncImmediately[12] (compression)	REGRESSION	🔴🔵	0 / 19
o.a.c.index.sai.cql.VectorCompaction100dTest.testOneToManyCompaction[dc false]	NEW	🔴🔴	0 / 19
o.a.c.index.sai.cql.VectorSiftSmallTest.testCompaction[ca false] (compression)	REGRESSION	🔴🔵	0 / 19

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Found 1 known test failures

[jkni]

LGTM. Thanks!