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Content Sealing & Garbage Collection Architecture

Membuss implements explicit content sealing and two-phase reachability garbage collection (core/store/seal.go, core/store/gc_tracker.go).

1. Content Sealing​

  • Unsealed Content: Ingested blocks that have not been explicitly pinned.
  • Sealed Content: Content marked for permanent retention. Seal(root) recursively walks the Merkle DAG from root and writes seal records under seal/ prefix in Pebble DB.

2. Two-Phase Garbage Collection (GC)​

  1. Phase 1 (Reachability Walk): Traverses all sealed roots (AllSealed()) and populates an in-memory reachability set.
  2. Phase 2 (Orphan Sweeping): Iterates over blk/ and dag/ key namespaces. Any key NOT in the reachability set AND older than minAge is deleted.
  3. Ingestion Grace Tracker (gcTracker): Protects recently uploaded blocks from concurrent GC sweeps using a configurable grace period window.