refactor: add thread-safety to FireboltDriver with RWMutex

[devin-ai-integration]

Add thread-safety to FireboltDriver with RWMutex

Summary

Added thread-safety to the FireboltDriver struct to enable safe concurrent access from multiple goroutines. The singleton driver instance registered via sql.Register("firebolt", &FireboltDriver{}) was previously not thread-safe, causing potential race conditions when accessed concurrently (e.g., in performance tests with multiple goroutines).

Key changes:

• Added sync.RWMutex field to FireboltDriver struct
• Implemented double-checked locking pattern in OpenConnector method for optimal performance
• Protected all field accesses in option functions with appropriate locks
• Used RLock/RUnlock for reads (allows concurrent reads) and Lock/Unlock for writes (exclusive access)

The implementation prioritizes performance by using a double-checked locking pattern - the common case where DSN hasn't changed uses a read lock for high concurrency, while the rare reinitialization case uses a write lock.

Review & Testing Checklist for Human

• Verify double-checked locking correctness - Review the OpenConnector method implementation to ensure the pattern is correct and race-free
• Performance impact testing - Run concurrent benchmarks to verify performance hasn't degraded significantly, especially for cached connection scenarios
• Integration testing with real concurrent workloads - Test with multiple goroutines accessing the driver simultaneously using real Firebolt connections (not just unit tests)

Notes

• All tests pass with Go race detector (go test -race) - no race conditions detected
• Only short tests were run - full integration tests with real Firebolt instances should be executed
• The performance optimization uses read locks for the common case (DSN unchanged) and write locks only for reinitialization

Link to Devin run: https://app.devin.ai/sessions/13544bc77c724e6fb35d3e5626975b17
Requested by: @ptiurin

[devin-ai-integration]

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[github-actions]

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

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

See analysis details on SonarQube Cloud