Repair Apache Pulsar Cursor Backlog Ack Hole

Pulsar subscription cursors often stall when a consumer deployment leaves a persistent hole between cumulative and individual acknowledgments. This skill identifies missing acknowledgment ranges and prepares bounded recovery plans to resolve backlogs without losing data.

What it does

• Evidence mapping compares mark-delete positions against pending acknowledgment sets to pinpoint gaps.
• Gap registration logs every missing range with specific source IDs and timestamps for auditability.
• Boundary testing analyzes redelivery and deduplication limits based on provided log samples.
• Validation planning generates safe replay gates to ensure cursor advancement does not skip active messages.

How it works

1. Analyze logs by ingesting cursor mark-delete ledgers and state configuration snapshots.
2. Crosscheck metadata including timestamps, identifiers, and version changes across the deployment timeline.
3. Classify findings using a strict discipline of verified, contradicted, or unverified observations.
4. Draft recovery gates that define explicit rollback paths and authorization requirements for state changes.

Frameworks & tools

Specifically designed for Apache Pulsar message brokers and persistent subscription cursors. It processes ledger snapshots, recovery logs, and deployment timelines.

Why this beats prompting it yourself

Standard prompts often guess at cursor positions or suggest risky resets that cause data loss. This skill enforces a rigorous evidence-based classification system, ensuring every inference is tied to a specific timestamped log entry.

Use cases

• Clear stuck cursors where the backlog won't budge despite active consumers.
• Audit ack holes after a consumer crash or rolling deployment failure.
• Validate replay safety before manually advancing a mark-delete ledger.

Known limitations

Requires local text files for ledgers and logs; it cannot fetch data from live cloud clusters or proprietary admin APIs.