triedb: manually truncate ancient db

Signed-off-by: jsvisa <delweng@gmail.com>

triedb/database.go

@@ -280,6 +280,17 @@ func (db *Database) Recover(target common.Hash) error {
 	return pdb.Recover(target)
 }
 
+// TruncateHead truncates all state histories in the freezer above the bottom state layer.
+// This operation is only supported by path-based database It's typically used during
+// state recovery to align the state histories with the current state.
+func (db *Database) TruncateHead() error {
+	pdb, ok := db.backend.(*pathdb.Database)
+	if !ok {
+		return errors.New("not supported")
+	}
+	return pdb.TruncateHead()
+}
+
 // Recoverable returns the indicator if the specified state is enabled to be
 // recovered. It's only supported by path-based database and will return an
 // error for others.

triedb/pathdb/database.go

@@ -502,14 +502,16 @@ func (db *Database) Recover(root common.Hash) error {
 	if err := db.diskdb.SyncKeyValue(); err != nil {
 		return err
 	}
-	_, err := truncateFromHead(db.stateFreezer, dl.stateID())
-	if err != nil {
-		return err
-	}
 	log.Debug("Recovered state", "root", root, "elapsed", common.PrettyDuration(time.Since(start)))
 	return nil
 }
 
+// TruncateHead truncates all state histories in the freezer above the bottom state layer.
+func (db *Database) TruncateHead() error {
+	_, err := truncateFromHead(db.stateFreezer, db.tree.bottom().stateID())
+	return err
+}
+
 // Recoverable returns the indicator if the specified state is recoverable.
 //
 // The supplied root must be a valid trie hash value.