.

wcfs/internal/xbtree/treediff.go

@@ -580,7 +580,8 @@ ABcov:
 	// by default a node contributes to δ-
 	// a node ac does not contribute to δ- and can be skipped, if:
 	// - ac is not tracked, or
-	// - ac ∉ δZTC && ∃ bc from B: ac.oid == bc.oid	(ac+ac.children were not changed, and ac stays in the tree)
+	// - ac ∉ δZTC && ∃ bc from B: ac.oid == bc.oid && ac.keyrange == bc.keyrange
+	//   (ac+ac.children were not changed, ac stays in the tree with the same key range coverage)
 	Aq := []*nodeInRange{atop} // queue for A nodes that contribute to δ-
 	for len(Aq) > 0 {
 		debugfDiff("\n")
@@ -667,30 +668,39 @@ ABcov:
 						}
 					}
 					if found {
-						// ac can be skipped
-						// adjust trackSet since path to the node could have changed
-						apath := ac.Path()
-						bpath := bc.Path()
-						if !pathEqual(apath, bpath) {
-							δtrack.Del.AddPath(apath)
-							δtrack.Add.AddPath(bpath)
-							if nc := at.nchild; nc != 0 {
-								δtrack.δnchildNonLeafs[acOid] = nc
-								// XXX debugDiff δtrack [) ...
+						// ac can be skipped if key coverage stays the same
+						ar := KeyRange{ac.lo, ac.hi_}
+						br := KeyRange{bc.lo, bc.hi_}
+						if ar == br {
+							// adjust trackSet since path to the node could have changed
+							apath := ac.Path()
+							bpath := bc.Path()
+							if !pathEqual(apath, bpath) {
+								δtrack.Del.AddPath(apath)
+								δtrack.Add.AddPath(bpath)
+								if nc := at.nchild; nc != 0 {
+									δtrack.δnchildNonLeafs[acOid] = nc
+									// XXX debugDiff δtrack [) ...
+								}
 							}
+
+							continue
 						}
 
+						/*
 						// adjust δtkeycov only if it was leaf bucket
 						if nc := at.nchild; nc == 0 {
 							ar := KeyRange{ac.lo, ac.hi_}
 							br := KeyRange{bc.lo, bc.hi_}
 							δtkeycovADel.AddRange(ar)
-							δtkeycovBAdd.AddRange(br)
+							//δtkeycovBAdd.AddRange(br)
+							// XXX remove KKK vvv
 							debugfDiff("  δtrack - %s %v KKK\n", ar, apath)
 							debugfDiff("  δtrack + %s %v KKK\n", br, bpath)
 						}
+						*/
 
-						continue
+//						continue
 					}
 				}
 

wcfs/internal/xbtree/δbtail_test.go

@@ -741,7 +741,8 @@ func xverifyΔBTail_Update1(t *testing.T, subj string, db *zodb.DB, treeRoot zod
 		}
 	}
 
-	TrackedδZ = SetKey{} // Tracked ^ δZ
+	// TrackedδZ = Tracked ^ δZ  (i.e. a tracked node has changed, or its coverage was changed)
+	TrackedδZ = SetKey{}
 	for k := range initialTrackedKeys {
 		leaf1 := xkv1.Get(k)
 		oid1 := leaf1.oid
@@ -753,7 +754,7 @@ func xverifyΔBTail_Update1(t *testing.T, subj string, db *zodb.DB, treeRoot zod
 		if oid2 == zodb.InvalidOid { // embedded bucket
 			oid2 = leaf2.parent.oid
 		}
-		if δZset.Has(oid1) || δZset.Has(oid2) {
+		if δZset.Has(oid1) || δZset.Has(oid2) || (KeyRange{leaf1.lo,leaf1.hi_} != KeyRange{leaf2.lo,leaf2.hi_}) {
 			TrackedδZ.Add(k)
 		}
 	}