diff --git a/wasm_parts/main.go b/wasm_parts/main.go
index 1c2bd9ca..490566b0 100644
--- a/wasm_parts/main.go
+++ b/wasm_parts/main.go
@@ -144,7 +144,7 @@ func stats() {
 //export pqlRangeQuery
 func pqlRangeQuery(id uint32, fromMS float64, toMS float64, stepMS float64) uint32 {
 	return pql(data[id], func() (promql.Query, error) {
-		queriable := &TestQueryable{id: id}
+		queriable := &TestQueryable{id: id, stepMs: int64(stepMS)}
 		return getEng().NewRangeQuery(
 			queriable,
 			nil,
@@ -159,7 +159,7 @@ func pqlRangeQuery(id uint32, fromMS float64, toMS float64, stepMS float64) uint
 //export pqlInstantQuery
 func pqlInstantQuery(id uint32, timeMS float64) uint32 {
 	return pql(data[id], func() (promql.Query, error) {
-		queriable := &TestQueryable{id: id}
+		queriable := &TestQueryable{id: id, stepMs: 15000}
 		return getEng().NewInstantQuery(
 			queriable,
 			nil,
@@ -170,7 +170,7 @@ func pqlInstantQuery(id uint32, timeMS float64) uint32 {
 
 //export pqlSeries
 func pqlSeries(id uint32) uint32 {
-	queriable := &TestQueryable{id: id}
+	queriable := &TestQueryable{id: id, stepMs: 15000}
 	query, err := getEng().NewRangeQuery(
 		queriable,
 		nil,
@@ -329,7 +329,8 @@ func (t TestLogger) Log(keyvals ...interface{}) error {
 }
 
 type TestQueryable struct {
-	id uint32
+	id     uint32
+	stepMs int64
 }
 
 func (t TestQueryable) Querier(ctx context.Context, mint, maxt int64) (storage.Querier, error) {
@@ -338,11 +339,12 @@ func (t TestQueryable) Querier(ctx context.Context, mint, maxt int64) (storage.Q
 	for r.i < uint32(len(data[t.id].request)) {
 		sets[r.ReadString()] = r.ReadByteArray()
 	}
-	return &TestQuerier{sets: sets}, nil
+	return &TestQuerier{sets: sets, stepMs: t.stepMs}, nil
 }
 
 type TestQuerier struct {
-	sets map[string][]byte
+	sets   map[string][]byte
+	stepMs int64
 }
 
 func (t TestQuerier) LabelValues(name string, matchers ...*labels.Matcher) ([]string, storage.Warnings, error) {
@@ -362,12 +364,14 @@ func (t TestQuerier) Select(sortSeries bool, hints *storage.SelectHints, matcher
 	return &TestSeriesSet{
 		data:   t.sets[strMatchers],
 		reader: BinaryReader{buffer: t.sets[strMatchers]},
+		stepMs: t.stepMs,
 	}
 }
 
 type TestSeriesSet struct {
 	data   []byte
 	reader BinaryReader
+	stepMs int64
 }
 
 func (t *TestSeriesSet) Next() bool {
@@ -376,10 +380,12 @@ func (t *TestSeriesSet) Next() bool {
 
 func (t *TestSeriesSet) At() storage.Series {
 	res := &TestSeries{
-		i: -1,
+		i:      0,
+		stepMs: t.stepMs,
 	}
 	res.labels = t.reader.ReadLabelsTuple()
 	res.data = t.reader.ReadPointsArrayRaw()
+	res.reset()
 	return res
 }
 
@@ -392,21 +398,63 @@ func (t *TestSeriesSet) Warnings() storage.Warnings {
 }
 
 type TestSeries struct {
-	data []byte
+	data   []byte
+	stepMs int64
 
-	labels labels.Labels
-	i      int
+	labels      labels.Labels
+	tsMs        int64
+	generatedMs int64
+	val         float64
+	i           int
+}
+
+func (t *TestSeries) reset() {
+	if len(t.data) == 0 {
+		return
+	}
+	t.tsMs = *(*int64)(unsafe.Pointer(&t.data[0]))
+	t.val = *(*float64)(unsafe.Pointer(&t.data[t.i*16+8]))
 }
 
 func (t *TestSeries) Next() bool {
+	if t.i*16 >= len(t.data) {
+		if t.generatedMs == 0 {
+			t.tsMs += t.stepMs
+			t.generatedMs += t.stepMs
+			return true
+		}
+		return false
+	}
+	ts := *(*int64)(unsafe.Pointer(&t.data[t.i*16]))
+	if ts-t.tsMs > t.stepMs && t.generatedMs < 300000 {
+		t.tsMs += t.stepMs
+		t.generatedMs += t.stepMs
+		return true
+	}
+	t.tsMs = ts
+	t.generatedMs = 0
+	t.val = *(*float64)(unsafe.Pointer(&t.data[t.i*16+8]))
 	t.i++
-	return t.i*16 < len(t.data)
+	return true
 }
 
 func (t *TestSeries) Seek(tmMS int64) bool {
 	for t.i = 0; t.i*16 < len(t.data); t.i++ {
 		ms := *(*int64)(unsafe.Pointer(&t.data[t.i*16]))
-		if ms >= tmMS {
+		if ms == tmMS {
+			t.tsMs = ms
+			t.val = *(*float64)(unsafe.Pointer(&t.data[t.i*16+8]))
+			t.i++
+			return true
+		}
+		if ms > tmMS {
+			t.i--
+			if t.i < 0 {
+				t.i = 0
+			}
+			t.tsMs = tmMS
+			t.val = *(*float64)(unsafe.Pointer(&t.data[t.i*16+8]))
+			t.i++
 			return true
 		}
 	}
@@ -414,9 +462,7 @@ func (t *TestSeries) Seek(tmMS int64) bool {
 }
 
 func (t *TestSeries) At() (int64, float64) {
-	ts := *(*int64)(unsafe.Pointer(&t.data[t.i*16]))
-	val := *(*float64)(unsafe.Pointer(&t.data[t.i*16+8]))
-	return ts, val
+	return t.tsMs, t.val
 }
 
 func (t *TestSeries) Err() error {
diff --git a/wasm_parts/main.wasm.gz b/wasm_parts/main.wasm.gz
index 300d4ed7..76e5ab38 100644
Binary files a/wasm_parts/main.wasm.gz and b/wasm_parts/main.wasm.gz differ