.

wcfs/δbtail.go

@@ -177,7 +177,7 @@ type ΔBtail struct {
 	trackNew SetOid
 
 
-	// tracked nodes index: node -> parent + keys tracked under this node
+	// tracked nodes index: node -> parent + accessed holes under this node
 	trackIdx map[zodb.Oid]nodeTrack
 }
 
@@ -185,8 +185,7 @@ type ΔBtail struct {
 // nodeTrack represents tracking information about a node.
 type nodeTrack struct {
 	parent  zodb.Oid // parent node | InvalidOid for root
-	holes   SetKey   // missing keys tracked under this node  XXX nil for root(?) XXX only !empty root
-//	trackedKeys SetKey // XXX kill
+	holes   SetKey   // missing keys tracked under this node;  nil for !leaf
 }
 
 // ΔB represents a change in BTrees space.
@@ -295,12 +294,15 @@ func (δBtail *ΔBtail) Track(key Key, keyPresent bool, path []Node, flags Track
 	parent := zodb.InvalidOid
 	var track    nodeTrack
 	var oldTrack bool
-	for _, node := range path {
+	for i, node := range path {
 		oid := node.POid()
 		// XXX check for InvalidOid  (e.g. T/B1:a with bucket not having its own oid.
 		track, oldTrack = δBtail.trackIdx[oid]
 		if !oldTrack {
-			track = nodeTrack{parent: parent, holes: SetKey{}}
+			track = nodeTrack{parent: parent}
+			if i == l-1 { // leaf
+				track.holes = SetKey{}
+			}
 			δBtail.trackIdx[oid] = track
 			// XXX .trackNew += oid
 		}