Minor comment

pkg/txn/c_scheduler.go

@@ -9,7 +9,11 @@ type Scheduler struct {
 	sync.Mutex
 	nextTs uint64
 
-	readVisibilityWaiter   *TsWaiter
+	// `readTsMarker` marks the visibility(ts) of read operations in a `newTransaction` to other transactions.
+	// Here we don't need TsWaiter as such, as we are not using the `WaitFor` API. However,
+	// we are using the `DoneTill` API to get the last completed readTs to remove the old readyToCommitTxns.
+	readTsMarker *TsWaiter
+	// `commitVisibilityWaiter` blocks `newTransaction` to ensure previous commits are visible to new reads.
 	commitVisibilityWaiter *TsWaiter
 
 	readyToCommitTxns []ReadyToCommitTxn
@@ -18,17 +22,17 @@ type Scheduler struct {
 func NewScheduler() *Scheduler {
 	scheduler := &Scheduler{
 		nextTs:                 1,
-		readVisibilityWaiter:   NewTsWaiter(),
+		readTsMarker:           NewTsWaiter(),
 		commitVisibilityWaiter: NewTsWaiter(),
 	}
 
-	scheduler.readVisibilityWaiter.Done(scheduler.nextTs - 1)
+	scheduler.readTsMarker.Done(scheduler.nextTs - 1)
 	scheduler.commitVisibilityWaiter.Done(scheduler.nextTs - 1)
 	return scheduler
 }
 
 func (o *Scheduler) Stop() {
-	o.readVisibilityWaiter.Stop()
+	o.readTsMarker.Stop()
 	o.commitVisibilityWaiter.Stop()
 }
 
@@ -37,7 +41,7 @@ func (o *Scheduler) NewReadTs() uint64 {
 	defer o.Unlock()
 
 	beginTimestamp := o.nextTs - 1
-	o.readVisibilityWaiter.Begin(beginTimestamp)
+	o.readTsMarker.Begin(beginTimestamp)
 
 	err := o.commitVisibilityWaiter.WaitFor(context.Background(), beginTimestamp)
 	if err != nil {
@@ -73,7 +77,7 @@ func (o *Scheduler) NewCommitTs(transaction *Txn) (uint64, error) {
 }
 
 func (o *Scheduler) DoneRead(transaction *Txn) {
-	o.readVisibilityWaiter.Done(transaction.snapshot.ts)
+	o.readTsMarker.Done(transaction.snapshot.ts)
 }
 
 func (o *Scheduler) DoneCommit(commitTs uint64) {
@@ -98,7 +102,7 @@ func (o *Scheduler) hasConflictFor(txn *Txn) bool {
 
 func (o *Scheduler) gcOldReadyToCommitTxns() {
 	updatedReadyToCommitTxns := o.readyToCommitTxns[:0]
-	lastCommittedTxnTs := o.readVisibilityWaiter.DoneTill()
+	lastCommittedTxnTs := o.readTsMarker.DoneTill()
 
 	for _, readyToCommitTxn := range o.readyToCommitTxns {
 		if readyToCommitTxn.commitTs <= lastCommittedTxnTs {