allow single iteration to traverseOrphans with target version

nodedb.go

@@ -449,13 +449,30 @@ func (ndb *nodeDB) DeleteVersionsFrom(version int64, fastMode bool) error {
 		if err != nil {
 			return err
 		}
-	}
+		// Next, delete orphans:
+		// - Delete orphan entries *and referred nodes* with fromVersion >= version
+		// - Delete orphan entries with toVersion >= version-1 (since orphans at latest are not orphans)
+		err = ndb.traverseOrphans(func(key, hash []byte) error {
+			var fromVersion, toVersion int64
+			orphanKeyFormat.Scan(key, &toVersion, &fromVersion)
 
-	// Next, delete orphans:
-	// - Delete orphan entries *and referred nodes* with fromVersion >= version
-	// - Delete orphan entries with toVersion >= version-1 (since orphans at latest are not orphans)
-	for v := version - 1; v <= latest; v++ {
-		err = ndb.traverseOrphansVersion(v, func(key, hash []byte) error {
+			if fromVersion >= version {
+				if err = ndb.batch.Delete(key); err != nil {
+					return err
+				}
+				if err = ndb.batch.Delete(ndb.nodeKey(hash)); err != nil {
+					return err
+				}
+				ndb.nodeCache.Remove(hash)
+			} else if toVersion >= version-1 {
+				if err = ndb.batch.Delete(key); err != nil {
+					return err
+				}
+			}
+			return nil
+		})
+	} else {
+		err = ndb.traverseOrphansVersion(version, func(key, hash []byte) error {
 			var fromVersion, toVersion int64
 			orphanKeyFormat.Scan(key, &toVersion, &fromVersion)
 			if fromVersion >= version {
@@ -473,10 +490,9 @@ func (ndb *nodeDB) DeleteVersionsFrom(version int64, fastMode bool) error {
 			}
 			return nil
 		})
-
-		if err != nil {
-			return err
-		}
+	}
+	if err != nil {
+		return err
 	}
 
 	// Delete the version root entries