Database used to resolve live entity references
Changes produced by a transaction or undo record
Entity buckets keyed by the kind of structural or property change
Entities appended to a block table record
Entities removed from a block table record
Entities whose properties were modified
Collects entities affected by changes for post-commit/undo/redo event dispatch.
Only block-table-record append/remove operations contribute to the appended and erased lists; modify entries always resolve through object IDs.