.

wcfs/internal/xbtree/δbtail.go

@@ -110,9 +110,6 @@ type _ΔTtail struct {
 	// which vδT was not yet rebuilt
 	trackNew blib.PPTreeSubSet
 	// XXX + trackNewKeys RangedKeySet (concurrency)
-
-	// index for GetAt queries
-	lastRevOf map[Key]zodb.Tid // {} key -> last revision
 }
 
 // _ΔBroots represents roots-only part of ΔB.
@@ -158,7 +155,6 @@ func NewΔBtail(at0 zodb.Tid, db *zodb.DB) *ΔBtail {
 func newΔTtail() *_ΔTtail {
 	return &_ΔTtail{
 		trackNew:  blib.PPTreeSubSet{},
-		lastRevOf: make(map[Key]zodb.Tid),
 	}
 }
 
@@ -200,10 +196,6 @@ func (orig *_ΔTtail) Clone() *_ΔTtail {
 	klon := &_ΔTtail{}
 	klon.vδT = vδTClone(orig.vδT)
 	klon.trackNew = orig.trackNew.Clone()
-	klon.lastRevOf = make(map[Key]zodb.Tid, len(orig.lastRevOf))
-	for k, rev := range orig.lastRevOf {
-		klon.lastRevOf[k] = rev
-	}
 	return klon
 }
 
@@ -389,8 +381,6 @@ func (δTtail *_ΔTtail) rebuild(root zodb.Oid, δZtail *zodb.ΔTail, db *zodb.D
 			if newRevEntry {
 				δrevSet.Add(δZ.Rev)
 			}
-
-			// XXX update .lastRevOf
 		}
 
 		// an iteration closer to tail may turn out to add a key to the tracking set.
@@ -547,7 +537,6 @@ func (δTtail *_ΔTtail) rebuild1(atPrev zodb.Tid, δZ zodb.ΔRevEntry, trackNew
 		}
 	}
 
-	// XXX update .lastRevOf	(here?)
 	return δtrack, δtkeycov, newRevEntry, nil
 }
 
@@ -601,8 +590,6 @@ func (δBtail *ΔBtail) Update(δZ *zodb.EventCommit) (_ ΔB, err error) {
 				δB.ByRoot[root] = δT.KV
 			}
 		}
-
-		// XXX rebuild lastRevOf
 	}
 
 	// vδBroots += δB  (δB.Rev could be already there added by ^^^ rebuild)
@@ -744,7 +731,6 @@ func (δBtail *ΔBtail) ForgetPast(revCut zodb.Tid) {
 
 func (δTtail *_ΔTtail) forgetPast(revCut zodb.Tid) {
 	// XXX locking
-	// XXX lastRevOf
 
 	icut := 0
 	for ; icut < len(δTtail.vδT); icut++ {

wcfs/internal/xbtree/δbtail_test.go

@@ -1519,7 +1519,6 @@ func _KAdj(t1, t2 *xbtreetest.Commit, keysv ...setKey) (kadj KAdjMatrix) {
 // it also verifies that δbtail.vδBroots matches ΔTtail data.
 func assertΔTtail(t *testing.T, subj string, δbtail *ΔBtail, tj *xbtreetest.Commit, treeRoot zodb.Oid, vδTok ...map[Key]Δstring) {
 	t.Helper()
-	// XXX +lastRevOf
 
 	T := tj.T // XXX better require t to be xbtreetest.T instead?