diff --git a/dashboard/app/build/build.go b/dashboard/app/build/build.go
index 0401cd2cd2b..8a135cf9812 100644
--- a/dashboard/app/build/build.go
+++ b/dashboard/app/build/build.go
@@ -315,28 +315,50 @@ func GetCommits(c appengine.Context, startCommitNum, n int) ([]*Commit, error) {
 	if startCommitNum < 0 || n <= 0 {
 		return nil, fmt.Errorf("GetCommits: invalid args (%v, %v)", startCommitNum, n)
 	}
-	var res []*Commit
-	for n > 0 {
-		cr, err := GetCommitRun(c, startCommitNum)
+
+	p := &Package{}
+	t := datastore.NewQuery("CommitRun").
+		Ancestor(p.Key(c)).
+		Filter("StartCommitNum >=", startCommitNum/PerfRunLength*PerfRunLength).
+		Order("StartCommitNum").
+		Limit(100).
+		Run(c)
+
+	res := make([]*Commit, n)
+	for {
+		cr := new(CommitRun)
+		_, err := t.Next(cr)
+		if err == datastore.Done {
+			break
+		}
 		if err != nil {
 			return nil, err
 		}
-		idx := startCommitNum - cr.StartCommitNum
-		cnt := PerfRunLength - idx
-		if cnt > n {
-			cnt = n
+		if cr.StartCommitNum >= startCommitNum+n {
+			break
 		}
-		for i := idx; i < idx+cnt; i++ {
+		// Calculate start index for copying.
+		i := 0
+		if cr.StartCommitNum < startCommitNum {
+			i = startCommitNum - cr.StartCommitNum
+		}
+		// Calculate end index for copying.
+		e := PerfRunLength
+		if cr.StartCommitNum+e > startCommitNum+n {
+			e = startCommitNum + n - cr.StartCommitNum
+		}
+		for ; i < e; i++ {
 			com := new(Commit)
 			com.Hash = cr.Hash[i]
 			com.User = cr.User[i]
 			com.Desc = cr.Desc[i]
 			com.Time = cr.Time[i]
 			com.NeedsBenchmarking = cr.NeedsBenchmarking[i]
-			res = append(res, com)
+			res[cr.StartCommitNum-startCommitNum+i] = com
+		}
+		if e != PerfRunLength {
+			break
 		}
-		startCommitNum += cnt
-		n -= cnt
 	}
 	return res, nil
 }
@@ -535,22 +557,47 @@ func GetPerfMetricsForCommits(c appengine.Context, builder, benchmark, metric st
 	if startCommitNum < 0 || n <= 0 {
 		return nil, fmt.Errorf("GetPerfMetricsForCommits: invalid args (%v, %v)", startCommitNum, n)
 	}
-	var res []uint64
-	for n > 0 {
-		metrics, err := GetPerfMetricRun(c, builder, benchmark, metric, startCommitNum)
+
+	p := &Package{}
+	t := datastore.NewQuery("PerfMetricRun").
+		Ancestor(p.Key(c)).
+		Filter("Builder =", builder).
+		Filter("Benchmark =", benchmark).
+		Filter("Metric =", metric).
+		Filter("StartCommitNum >=", startCommitNum/PerfRunLength*PerfRunLength).
+		Order("StartCommitNum").
+		Limit(100).
+		Run(c)
+
+	res := make([]uint64, n)
+	for {
+		metrics := new(PerfMetricRun)
+		_, err := t.Next(metrics)
+		if err == datastore.Done {
+			break
+		}
 		if err != nil {
 			return nil, err
 		}
-		idx := startCommitNum - metrics.StartCommitNum
-		cnt := PerfRunLength - idx
-		if cnt > n {
-			cnt = n
+		if metrics.StartCommitNum >= startCommitNum+n {
+			break
 		}
-		for _, v := range metrics.Vals[idx : idx+cnt] {
-			res = append(res, uint64(v))
+		// Calculate start index for copying.
+		i := 0
+		if metrics.StartCommitNum < startCommitNum {
+			i = startCommitNum - metrics.StartCommitNum
+		}
+		// Calculate end index for copying.
+		e := PerfRunLength
+		if metrics.StartCommitNum+e > startCommitNum+n {
+			e = startCommitNum + n - metrics.StartCommitNum
+		}
+		for ; i < e; i++ {
+			res[metrics.StartCommitNum-startCommitNum+i] = uint64(metrics.Vals[i])
+		}
+		if e != PerfRunLength {
+			break
 		}
-		startCommitNum += cnt
-		n -= cnt
 	}
 	return res, nil
 }
diff --git a/dashboard/app/build/perf_graph.go b/dashboard/app/build/perf_graph.go
index 647d58777de..7a660e4b711 100644
--- a/dashboard/app/build/perf_graph.go
+++ b/dashboard/app/build/perf_graph.go
@@ -231,7 +231,7 @@ func perfGraphHandler(w http.ResponseWriter, r *http.Request) {
 		idx := 0
 		for i := range vals[0] {
 			com := commits2[i]
-			if !com.NeedsBenchmarking {
+			if com == nil || !com.NeedsBenchmarking {
 				continue
 			}
 			c := perfGraphCommit{Id: idx, Name: fmt.Sprintf("%v (%v)", com.Desc, com.Time.Format("Jan 2, 2006 1:04"))}
diff --git a/dashboard/app/build/perf_learn.go b/dashboard/app/build/perf_learn.go
index 32b8fdf1b98..683ba60b09b 100644
--- a/dashboard/app/build/perf_learn.go
+++ b/dashboard/app/build/perf_learn.go
@@ -67,7 +67,7 @@ func perfLearnHandler(w http.ResponseWriter, r *http.Request) {
 					last := uint64(0)
 					for i, v := range values {
 						if v == 0 {
-							if commits[i].NeedsBenchmarking {
+							if com := commits[i]; com == nil || com.NeedsBenchmarking {
 								last = 0
 							}
 							continue
diff --git a/dashboard/app/index.yaml b/dashboard/app/index.yaml
index 76dd09ec8d0..670a667f5ba 100644
--- a/dashboard/app/index.yaml
+++ b/dashboard/app/index.yaml
@@ -37,3 +37,18 @@ indexes:
   - name: CommitNum
     direction: asc
 
+- kind: CommitRun
+  ancestor: yes
+  properties:
+  - name: StartCommitNum
+    direction: asc
+
+- kind: PerfMetricRun
+  ancestor: yes
+  properties:
+  - name: Builder
+  - name: Benchmark
+  - name: Metric
+  - name: StartCommitNum
+    direction: asc
+