Core System Refactoring for Fraction Management Consistency and Performance

Primary Goals:

• Ensure State Consistency During S3 Offloading: Prevent fractions from temporarily disappearing during upload, which causes unstable and unpredictable search results.
• Fix Interface Segregation Principle (ISP) Violation: The Fraction interface currently forces all implementations to define an Offloading method, which is only relevant for a specific type. This requires others to provide meaningless stub methods.
• Unblock Compaction: Establish a clear and reliable state management system for fractions to correctly identify candidates for the compaction process.
• Queue Size Control & Overflow Handling: Implement monitoring and size limiting mechanisms for the Offloading and Sealing queues. Develop an overflow strategy (e.g., rejecting new tasks or eviction).

Secondary Goals (Optimization & Refactoring):

• Simplify Fraction Interface: Remove DataProvider by moving its Search and Fetch methods directly into the Fraction interface.
• Simplify Fraction Implementations: Remove internal mutexes from active and sealed fraction implementations. Thread safety will be centralized and handled by the FractionManager.
• Cache Fraction List: Cache the list of fractions in FractionManager and update it only upon actual changes (add/remove), instead of rebuilding it before every search operation.
• Optimize Statistics Calculation: Shift from a periodic full recalculation (every 10 seconds) to an incremental update model. Statistics will be updated after every change to the fraction composition, reducing system load.

No files, tests, or entry points are named. Start by locating Fraction, FractionManager, DataProvider, and the Offloading and Sealing queues, then trace state changes during S3 offloading and compaction. Done means the listed consistency, interface, queue, caching, and statistics goals are implemented and verified by the project’s relevant tests.