[CASSANDRA-15461] Legacy counter shards can cause false positives in repaired data tracking

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 4.0-alpha3, 4.0
• Component/s: Observability/Metrics
• Bug Category: Correctness
• Severity: Normal
• Complexity: Normal
• Discovered By: Code Inspection
• Platform: All
• Since Version: 4.0-alpha

Source Control Link

https://github.com/apache/cassandra/commit/39eb7db65fd45653fdece1087ba75c3356a10c97

Test and Documentation Plan

Updated unit tests

• Assignee: Sam Tunnicliffe
• Reporter: Sam Tunnicliffe

Authors

Sam Tunnicliffe

Reviewers

Marcus Eriksson

• Created: 19/Dec/19 13:07
• Updated: 21/Dec/20 08:08
• Resolved: 23/Jan/20 10:21

Description

It is expected that the serialization of legacy (pre-2.1) counter cells may differ across replicas due to the remote vs local designation of the shards. This will cause the repaired data digests calculated at read time to differ where certain legacy shards are encountered. This does not, however, indicate corruption of the repaired dataset and there isn't any action that operators can take in this scenario. Excluding counter cells which contain legacy shards from the digest calculation will avoid false positives.

Issue Links

• is depended upon by: CASSANDRA-15462 Purgable tombstones can cause false positives in repaired data tracking