Phase 5 Benchmark Comparison: SQLite Cache Migration

Date: 2025-11-30 Migration: MapDB → SQLite for Thumbnail and EXIF caches

Summary

Phase 5 migrated the thumbnail and EXIF caches from MapDB to SQLite. This document compares benchmark results before and after the migration.

Cache Benchmark Results

Thumbnail Cache

EXIF Cache

Analysis

Performance Parity Achieved

The SQLite implementation achieves performance parity with the previous MapDB implementation:

1. Single-threaded operations: Read and write latencies are equivalent
2. Concurrent access: Multi-threaded benchmarks show identical throughput
3. Existence checks: Both cacheExists and containsUpToDate maintain sub-microsecond performance

Advantages of SQLite

While performance is equivalent, SQLite provides additional benefits:

1. Unified backend: Single database technology for all storage
2. Better tooling: Standard SQLite tools for debugging and inspection
3. Reduced dependencies: MapDB jar removed from project
4. Simpler architecture: Consistent connection handling across modules

Benchmark Configuration

• JMH Version: 1.37
• JVM: OpenJDK 21.0.9
• Warmup: 2 iterations, 1 second each
• Measurement: 5 iterations, 1 second each
• Forks: 1

Files

• Pre-migration baseline: docs/benchmarks/pre-phase5-cache.json
• Post-migration results: docs/benchmarks/post-phase5-cache.json

Conclusion

The Phase 5 SQLite cache migration successfully replaced MapDB while maintaining equivalent performance characteristics. The migration eliminates a dependency, simplifies the codebase architecture, and provides better debugging tooling without sacrificing performance.