{"id":"gc-not-thread-safe","text":"`garbage_collect()` mutates `_versions` (replacing lists and deleting keys) without synchronization, assuming single-threaded execution — concurrent reads or writes during GC would race on the dict and its lists.","truth_value":"IN","source":"entries/2026/05/29/snapshot-isolation-mvcc_database-garbage_collect.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"explanation":{"steps":[{"node":"gc-not-thread-safe","truth_value":"IN","reason":"premise"}]}}