comment

Author: danlaine

storage/src/qmdb/immutable/mod.rs

@@ -5,6 +5,22 @@
 //! - [fixed]: For fixed-size values.
 //! - [variable]: For variable-size values.
 //!
+//! # Inactivity floor
+//!
+//! Each commit carries an inactivity floor: a location before which the application
+//! declares operations are no longer needed. The floor is embedded in the operation
+//! log and included in the Merkle root, so all replicas processing the same operations
+//! arrive at the same floor.
+//!
+//! The floor controls two things:
+//! - **Pruning**: [`Immutable::prune`] only allows pruning up to the floor.
+//! - **Reconstruction**: on restart or sync, the snapshot is rebuilt from the floor
+//!   onward. Keys set before the floor are not loaded into memory.
+//!
+//! The floor must be monotonically non-decreasing across commits and must not exceed
+//! the batch's total operation count. Pass `db.inactivity_floor_loc()` to keep the
+//! floor unchanged, or a higher value to advance it.
+//!
 //! # Examples
 //!
 //! ```ignore