.

wcfs/internal/xbtree/δbtail.go

@@ -91,6 +91,16 @@ package xbtree
 //    further processed when a query should need keys from keycov. vδT is not
 //    yet providing data for keycov keys.
 //
+//    when a Track request starts to be processed, its keys and nodes are moved
+//    from ktrackNew/trackNew into krebuildJobs. vδT is not yet providing data
+//    for requested-to-be-tracked keys.
+//
+//    all trackSet, trackNew/ktrackNew and krebuildJobs are completely disjoint:
+//
+//	trackSet ^ trackNew     = ø
+//	trackSet ^ krebuildJobs = ø
+//	trackNew ^ krebuildJobs = ø
+//
 // 3. when a query is served, it needs to retrieve vδT snapshot that takes
 //    related previous Track requests into account. Retrieving such snapshots
 //    is implemented in vδTSnapForTracked*() family of functions: there it
@@ -522,7 +532,7 @@ func (δBtail *ΔBtail) vδTSnapForTrackedKey(root zodb.Oid, key Key) (vδT []Δ
 		return vδT, job.err
 	}
 
-	// key ∈ ktrackNew  ->  this goroutine becomes responsible to start rebuilding vδT for it
+	// key ∈ ktrackNew  ->  this goroutine becomes responsible to rebuild vδT for it
 	// run rebuild job for all keys queued in ktrackNew so far
 	err = δTtail._rebuild(root, δBtail)
 	if err == nil {