diff --git a/storage/buffer.go b/storage/buffer.go
index b3c789e97d..651e5c83e8 100644
--- a/storage/buffer.go
+++ b/storage/buffer.go
@@ -306,10 +306,9 @@ func (r *sampleRing) reset() {
 	r.iBuf = r.iBuf[:0]
 }
 
-// Returns the current iterator. Invalidates previously returned iterators.
+// Resets and returns the iterator. Invalidates previously returned iterators.
 func (r *sampleRing) iterator() *SampleRingIterator {
-	r.it.r = r
-	r.it.i = -1
+	r.it.reset(r)
 	return &r.it
 }
 
@@ -324,6 +323,13 @@ type SampleRingIterator struct {
 	fh *histogram.FloatHistogram
 }
 
+func (it *SampleRingIterator) reset(r *sampleRing) {
+	it.r = r
+	it.i = -1
+	it.h = nil
+	it.fh = nil
+}
+
 func (it *SampleRingIterator) Next() chunkenc.ValueType {
 	it.i++
 	if it.i >= it.r.l {
diff --git a/storage/buffer_test.go b/storage/buffer_test.go
index 61074c2122..1b24e5da22 100644
--- a/storage/buffer_test.go
+++ b/storage/buffer_test.go
@@ -138,6 +138,69 @@ func TestSampleRingMixed(t *testing.T) {
 	require.Equal(t, chunkenc.ValNone, it.Next())
 }
 
+func TestSampleRingAtFloatHistogram(t *testing.T) {
+	fh1 := tsdbutil.GenerateTestFloatHistogram(1)
+	fh2 := tsdbutil.GenerateTestFloatHistogram(2)
+	h1 := tsdbutil.GenerateTestHistogram(3)
+	h2 := tsdbutil.GenerateTestHistogram(4)
+
+	// With ValNone as the preferred type, nothing should be initialized.
+	r := newSampleRing(10, 2, chunkenc.ValNone)
+	require.Zero(t, len(r.fBuf))
+	require.Zero(t, len(r.hBuf))
+	require.Zero(t, len(r.fhBuf))
+	require.Zero(t, len(r.iBuf))
+
+	var (
+		h  *histogram.Histogram
+		fh *histogram.FloatHistogram
+		ts int64
+	)
+
+	it := r.iterator()
+	require.Equal(t, chunkenc.ValNone, it.Next())
+
+	r.addFH(fhSample{t: 1, fh: fh1})
+	r.addFH(fhSample{t: 2, fh: fh2})
+
+	it = r.iterator()
+
+	require.Equal(t, chunkenc.ValFloatHistogram, it.Next())
+	ts, fh = it.AtFloatHistogram(fh)
+	require.Equal(t, int64(1), ts)
+	require.Equal(t, fh1, fh)
+	require.Equal(t, chunkenc.ValFloatHistogram, it.Next())
+	ts, fh = it.AtFloatHistogram(fh)
+	require.Equal(t, int64(2), ts)
+	require.Equal(t, fh2, fh)
+	require.Equal(t, chunkenc.ValNone, it.Next())
+
+	r.reset()
+	it = r.iterator()
+	require.Equal(t, chunkenc.ValNone, it.Next())
+
+	r.addH(hSample{t: 3, h: h1})
+	r.addH(hSample{t: 4, h: h2})
+
+	it = r.iterator()
+
+	require.Equal(t, chunkenc.ValHistogram, it.Next())
+	ts, h = it.AtHistogram()
+	require.Equal(t, int64(3), ts)
+	require.Equal(t, h1, h)
+	ts, fh = it.AtFloatHistogram(fh)
+	require.Equal(t, int64(3), ts)
+	require.Equal(t, h1.ToFloat(nil), fh)
+	require.Equal(t, chunkenc.ValHistogram, it.Next())
+	ts, h = it.AtHistogram()
+	require.Equal(t, int64(4), ts)
+	require.Equal(t, h2, h)
+	ts, fh = it.AtFloatHistogram(fh)
+	require.Equal(t, int64(4), ts)
+	require.Equal(t, h2.ToFloat(nil), fh)
+	require.Equal(t, chunkenc.ValNone, it.Next())
+}
+
 func TestBufferedSeriesIterator(t *testing.T) {
 	var it *BufferedSeriesIterator