diff --git a/cmd/updater/main.go b/cmd/updater/main.go
index d07c72922..07d625628 100644
--- a/cmd/updater/main.go
+++ b/cmd/updater/main.go
@@ -163,10 +163,10 @@ func main() {
 	})
 	log.Info("Configured concurrency")
 
-	groupUpdater := updater.GCS(ctx, client, opt.groupTimeout, opt.buildTimeout, opt.buildConcurrency, opt.confirm, opt.enableIgnoreSkip)
-
 	mets := updater.CreateMetrics(prometheus.NewFactory())
 
+	groupUpdater := updater.GCS(ctx, client, mets, opt.groupTimeout, opt.buildTimeout, opt.buildConcurrency, opt.confirm, opt.enableIgnoreSkip)
+
 	pubsubClient, err := gpubsub.NewClient(ctx, "", option.WithCredentialsFile(opt.creds))
 	if err != nil {
 		logrus.WithError(err).Fatal("Failed to create pubsub client")
diff --git a/pkg/updater/updater.go b/pkg/updater/updater.go
index b3bbae8bc..d29326df2 100644
--- a/pkg/updater/updater.go
+++ b/pkg/updater/updater.go
@@ -49,15 +49,17 @@ const componentName = "updater"
 
 // Metrics holds metrics relevant to the Updater.
 type Metrics struct {
-	UpdateState  metrics.Cyclic
-	DelaySeconds metrics.Duration
+	UpdateState       metrics.Cyclic
+	DelaySeconds      metrics.Duration
+	IncompleteUpdates metrics.Counter
 }
 
 // CreateMetrics creates metrics for this controller
 func CreateMetrics(factory metrics.Factory) *Metrics {
 	return &Metrics{
-		UpdateState:  factory.NewCyclic(componentName),
-		DelaySeconds: factory.NewDuration("delay", "Seconds updater is behind schedule", "component"),
+		UpdateState:       factory.NewCyclic(componentName),
+		DelaySeconds:      factory.NewDuration("delay", "Seconds updater is behind schedule", "component"),
+		IncompleteUpdates: factory.NewCounter("incomplete-updates", "number of update attempts that don't complete"),
 	}
 }
 
@@ -88,7 +90,7 @@ func (mets *Metrics) start() *metrics.CycleReporter {
 type GroupUpdater func(parent context.Context, log logrus.FieldLogger, client gcs.Client, tg *configpb.TestGroup, gridPath gcs.Path) (bool, error)
 
 // GCS returns a GCS-based GroupUpdater, which knows how to process result data stored in GCS.
-func GCS(poolCtx context.Context, colClient gcs.Client, groupTimeout, buildTimeout time.Duration, concurrency int, write bool, enableIgnoreSkip bool) GroupUpdater {
+func GCS(poolCtx context.Context, colClient gcs.Client, mets *Metrics, groupTimeout, buildTimeout time.Duration, concurrency int, write bool, enableIgnoreSkip bool) GroupUpdater {
 	var readResult *resultReader
 	if poolCtx == nil {
 		// TODO(fejta): remove check soon
@@ -105,7 +107,7 @@ func GCS(poolCtx context.Context, colClient gcs.Client, groupTimeout, buildTimeo
 		defer cancel()
 		gcsColReader := gcsColumnReader(colClient, buildTimeout, readResult, enableIgnoreSkip)
 		reprocess := 20 * time.Minute // allow 20m for prow to finish uploading artifacts
-		return InflateDropAppend(ctx, log, client, tg, gridPath, write, gcsColReader, reprocess)
+		return InflateDropAppend(ctx, log, client, tg, gridPath, write, gcsColReader, reprocess, mets)
 	}
 }
 
@@ -567,7 +569,7 @@ func SortStarted(cols []InflatedColumn) {
 const byteCeiling = 2e6 // 2 megabytes
 
 // InflateDropAppend updates groups by downloading the existing grid, dropping old rows and appending new ones.
-func InflateDropAppend(ctx context.Context, alog logrus.FieldLogger, client gcs.Client, tg *configpb.TestGroup, gridPath gcs.Path, write bool, readCols ColumnReader, reprocess time.Duration) (bool, error) {
+func InflateDropAppend(ctx context.Context, alog logrus.FieldLogger, client gcs.Client, tg *configpb.TestGroup, gridPath gcs.Path, write bool, readCols ColumnReader, reprocess time.Duration, mets *Metrics) (bool, error) {
 	log := alog.(logrus.Ext1FieldLogger) // Add trace method
 	ctx, cancel := context.WithCancel(ctx)
 	defer cancel()
@@ -736,6 +738,7 @@ func InflateDropAppend(ctx context.Context, alog logrus.FieldLogger, client gcs.
 	}
 	if unreadColumns {
 		log = log.WithField("more", true)
+		mets.IncompleteUpdates.Add(1)
 	}
 	log.WithFields(logrus.Fields{
 		"cols":     len(grid.Columns),
diff --git a/pkg/updater/updater_test.go b/pkg/updater/updater_test.go
index 651705d46..36c52bd44 100644
--- a/pkg/updater/updater_test.go
+++ b/pkg/updater/updater_test.go
@@ -95,7 +95,7 @@ func TestGCS(t *testing.T) {
 					}
 				}
 			}()
-			updater := GCS(tc.ctx, nil, 0, 0, 0, false, false)
+			updater := GCS(tc.ctx, nil, nil, 0, 0, 0, false, false)
 			_, err := updater(ctx, logrus.WithField("case", tc.name), nil, tc.group, gcs.Path{})
 			switch {
 			case err != nil:
@@ -425,7 +425,7 @@ func TestUpdate(t *testing.T) {
 			if tc.groupUpdater == nil {
 				poolCtx, poolCancel := context.WithCancel(context.Background())
 				defer poolCancel()
-				tc.groupUpdater = GCS(poolCtx, client, *tc.groupTimeout, *tc.buildTimeout, tc.buildConcurrency, !tc.skipConfirm, false)
+				tc.groupUpdater = GCS(poolCtx, client, nil, *tc.groupTimeout, *tc.buildTimeout, tc.buildConcurrency, false, !tc.skipConfirm)
 			}
 			opts := &UpdateOptions{
 				ConfigPath:       configPath,
@@ -2059,6 +2059,7 @@ func TestInflateDropAppend(t *testing.T) {
 				!tc.skipWrite,
 				colReader,
 				tc.reprocess,
+				nil, //metric
 			)
 			switch {
 			case err != nil: