diff --git a/tsdb/querier.go b/tsdb/querier.go
index 3ae1c4f1e..642e089aa 100644
--- a/tsdb/querier.go
+++ b/tsdb/querier.go
@@ -426,6 +426,16 @@ func labelNamesWithMatchers(r IndexReader, matchers ...*labels.Matcher) ([]strin
 	return r.LabelNamesFor(postings...)
 }
 
+// These are the things fetched when we move from one series to another.
+type seriesData struct {
+	chks      []chunks.Meta
+	intervals tombstones.Intervals
+	labels    labels.Labels
+}
+
+// Labels implements part of storage.Series and storage.ChunkSeries.
+func (s *seriesData) Labels() labels.Labels { return s.labels }
+
 // blockBaseSeriesSet allows to iterate over all series in the single block.
 // Iterated series are trimmed with given min and max time as well as tombstones.
 // See newBlockSeriesSet and newBlockChunkSeriesSet to use it for either sample or chunk iterating.
@@ -438,8 +448,7 @@ type blockBaseSeriesSet struct {
 	mint, maxt      int64
 	disableTrimming bool
 
-	currIterFn func() *populateWithDelGenericSeriesIterator
-	currLabels labels.Labels
+	curr seriesData
 
 	bufChks []chunks.Meta
 	bufLbls labels.Labels
@@ -519,12 +528,11 @@ func (b *blockBaseSeriesSet) Next() bool {
 			intervals = intervals.Add(tombstones.Interval{Mint: b.maxt + 1, Maxt: math.MaxInt64})
 		}
 
-		b.currLabels = make(labels.Labels, len(b.bufLbls))
-		copy(b.currLabels, b.bufLbls)
+		b.curr.labels = make(labels.Labels, len(b.bufLbls))
+		copy(b.curr.labels, b.bufLbls)
+		b.curr.chks = chks
+		b.curr.intervals = intervals
 
-		b.currIterFn = func() *populateWithDelGenericSeriesIterator {
-			return newPopulateWithDelGenericSeriesIterator(b.blockID, b.chunks, chks, intervals)
-		}
 		return true
 	}
 	return false
@@ -556,29 +564,26 @@ type populateWithDelGenericSeriesIterator struct {
 	// the same, single series.
 	chks []chunks.Meta
 
-	i         int
+	i         int // Index into chks; -1 if not started yet.
 	err       error
-	bufIter   *DeletedIterator
+	bufIter   DeletedIterator // Retained for memory re-use. currDelIter may point here.
 	intervals tombstones.Intervals
 
 	currDelIter chunkenc.Iterator
 	currChkMeta chunks.Meta
 }
 
-func newPopulateWithDelGenericSeriesIterator(
-	blockID ulid.ULID,
-	chunks ChunkReader,
-	chks []chunks.Meta,
-	intervals tombstones.Intervals,
-) *populateWithDelGenericSeriesIterator {
-	return &populateWithDelGenericSeriesIterator{
-		blockID:   blockID,
-		chunks:    chunks,
-		chks:      chks,
-		i:         -1,
-		bufIter:   &DeletedIterator{},
-		intervals: intervals,
-	}
+func (p *populateWithDelGenericSeriesIterator) reset(blockID ulid.ULID, cr ChunkReader, chks []chunks.Meta, intervals tombstones.Intervals) {
+	p.blockID = blockID
+	p.chunks = cr
+	p.chks = chks
+	p.i = -1
+	p.err = nil
+	p.bufIter.Iter = nil
+	p.bufIter.Intervals = p.bufIter.Intervals[:0]
+	p.intervals = intervals
+	p.currDelIter = nil
+	p.currChkMeta = chunks.Meta{}
 }
 
 func (p *populateWithDelGenericSeriesIterator) next() bool {
@@ -618,28 +623,55 @@ func (p *populateWithDelGenericSeriesIterator) next() bool {
 
 	// We don't want the full chunk, or it's potentially still opened, take
 	// just a part of it.
-	p.bufIter.Iter = p.currChkMeta.Chunk.Iterator(nil)
-	p.currDelIter = p.bufIter
+	p.bufIter.Iter = p.currChkMeta.Chunk.Iterator(p.bufIter.Iter)
+	p.currDelIter = &p.bufIter
 	return true
 }
 
 func (p *populateWithDelGenericSeriesIterator) Err() error { return p.err }
 
-func (p *populateWithDelGenericSeriesIterator) toSeriesIterator() chunkenc.Iterator {
-	return &populateWithDelSeriesIterator{populateWithDelGenericSeriesIterator: p}
+type blockSeriesEntry struct {
+	chunks  ChunkReader
+	blockID ulid.ULID
+	seriesData
 }
 
-func (p *populateWithDelGenericSeriesIterator) toChunkSeriesIterator() chunks.Iterator {
-	return &populateWithDelChunkSeriesIterator{populateWithDelGenericSeriesIterator: p}
+func (s *blockSeriesEntry) Iterator(it chunkenc.Iterator) chunkenc.Iterator {
+	pi, ok := it.(*populateWithDelSeriesIterator)
+	if !ok {
+		pi = &populateWithDelSeriesIterator{}
+	}
+	pi.reset(s.blockID, s.chunks, s.chks, s.intervals)
+	return pi
+}
+
+type chunkSeriesEntry struct {
+	chunks  ChunkReader
+	blockID ulid.ULID
+	seriesData
+}
+
+func (s *chunkSeriesEntry) Iterator(it chunks.Iterator) chunks.Iterator {
+	pi, ok := it.(*populateWithDelChunkSeriesIterator)
+	if !ok {
+		pi = &populateWithDelChunkSeriesIterator{}
+	}
+	pi.reset(s.blockID, s.chunks, s.chks, s.intervals)
+	return pi
 }
 
 // populateWithDelSeriesIterator allows to iterate over samples for the single series.
 type populateWithDelSeriesIterator struct {
-	*populateWithDelGenericSeriesIterator
+	populateWithDelGenericSeriesIterator
 
 	curr chunkenc.Iterator
 }
 
+func (p *populateWithDelSeriesIterator) reset(blockID ulid.ULID, cr ChunkReader, chks []chunks.Meta, intervals tombstones.Intervals) {
+	p.populateWithDelGenericSeriesIterator.reset(blockID, cr, chks, intervals)
+	p.curr = nil
+}
+
 func (p *populateWithDelSeriesIterator) Next() chunkenc.ValueType {
 	if p.curr != nil {
 		if valueType := p.curr.Next(); valueType != chunkenc.ValNone {
@@ -701,11 +733,16 @@ func (p *populateWithDelSeriesIterator) Err() error {
 }
 
 type populateWithDelChunkSeriesIterator struct {
-	*populateWithDelGenericSeriesIterator
+	populateWithDelGenericSeriesIterator
 
 	curr chunks.Meta
 }
 
+func (p *populateWithDelChunkSeriesIterator) reset(blockID ulid.ULID, cr ChunkReader, chks []chunks.Meta, intervals tombstones.Intervals) {
+	p.populateWithDelGenericSeriesIterator.reset(blockID, cr, chks, intervals)
+	p.curr = chunks.Meta{}
+}
+
 func (p *populateWithDelChunkSeriesIterator) Next() bool {
 	if !p.next() {
 		return false
@@ -834,13 +871,11 @@ func newBlockSeriesSet(i IndexReader, c ChunkReader, t tombstones.Reader, p inde
 }
 
 func (b *blockSeriesSet) At() storage.Series {
-	// At can be looped over before iterating, so save the current value locally.
-	currIterFn := b.currIterFn
-	return &storage.SeriesEntry{
-		Lset: b.currLabels,
-		SampleIteratorFn: func(chunkenc.Iterator) chunkenc.Iterator {
-			return currIterFn().toSeriesIterator()
-		},
+	// At can be looped over before iterating, so save the current values locally.
+	return &blockSeriesEntry{
+		chunks:     b.chunks,
+		blockID:    b.blockID,
+		seriesData: b.curr,
 	}
 }
 
@@ -868,13 +903,11 @@ func newBlockChunkSeriesSet(id ulid.ULID, i IndexReader, c ChunkReader, t tombst
 }
 
 func (b *blockChunkSeriesSet) At() storage.ChunkSeries {
-	// At can be looped over before iterating, so save the current value locally.
-	currIterFn := b.currIterFn
-	return &storage.ChunkSeriesEntry{
-		Lset: b.currLabels,
-		ChunkIteratorFn: func(chunks.Iterator) chunks.Iterator {
-			return currIterFn().toChunkSeriesIterator()
-		},
+	// At can be looped over before iterating, so save the current values locally.
+	return &chunkSeriesEntry{
+		chunks:     b.chunks,
+		blockID:    b.blockID,
+		seriesData: b.curr,
 	}
 }
 
diff --git a/tsdb/querier_test.go b/tsdb/querier_test.go
index 20e4c2f8f..3b44cef51 100644
--- a/tsdb/querier_test.go
+++ b/tsdb/querier_test.go
@@ -859,7 +859,8 @@ func TestPopulateWithTombSeriesIterators(t *testing.T) {
 		t.Run(tc.name, func(t *testing.T) {
 			t.Run("sample", func(t *testing.T) {
 				f, chkMetas := createFakeReaderAndNotPopulatedChunks(tc.chks...)
-				it := newPopulateWithDelGenericSeriesIterator(ulid.ULID{}, f, chkMetas, tc.intervals).toSeriesIterator()
+				it := &populateWithDelSeriesIterator{}
+				it.reset(ulid.ULID{}, f, chkMetas, tc.intervals)
 
 				var r []tsdbutil.Sample
 				if tc.seek != 0 {
@@ -879,7 +880,8 @@ func TestPopulateWithTombSeriesIterators(t *testing.T) {
 			})
 			t.Run("chunk", func(t *testing.T) {
 				f, chkMetas := createFakeReaderAndNotPopulatedChunks(tc.chks...)
-				it := newPopulateWithDelGenericSeriesIterator(ulid.ULID{}, f, chkMetas, tc.intervals).toChunkSeriesIterator()
+				it := &populateWithDelChunkSeriesIterator{}
+				it.reset(ulid.ULID{}, f, chkMetas, tc.intervals)
 
 				if tc.seek != 0 {
 					// Chunk iterator does not have Seek method.
@@ -911,7 +913,8 @@ func TestPopulateWithDelSeriesIterator_DoubleSeek(t *testing.T) {
 		[]tsdbutil.Sample{sample{4, 4, nil, nil}, sample{5, 5, nil, nil}},
 	)
 
-	it := newPopulateWithDelGenericSeriesIterator(ulid.ULID{}, f, chkMetas, nil).toSeriesIterator()
+	it := &populateWithDelSeriesIterator{}
+	it.reset(ulid.ULID{}, f, chkMetas, nil)
 	require.Equal(t, chunkenc.ValFloat, it.Seek(1))
 	require.Equal(t, chunkenc.ValFloat, it.Seek(2))
 	require.Equal(t, chunkenc.ValFloat, it.Seek(2))
@@ -929,7 +932,8 @@ func TestPopulateWithDelSeriesIterator_SeekInCurrentChunk(t *testing.T) {
 		[]tsdbutil.Sample{},
 	)
 
-	it := newPopulateWithDelGenericSeriesIterator(ulid.ULID{}, f, chkMetas, nil).toSeriesIterator()
+	it := &populateWithDelSeriesIterator{}
+	it.reset(ulid.ULID{}, f, chkMetas, nil)
 	require.Equal(t, chunkenc.ValFloat, it.Next())
 	ts, v := it.At()
 	require.Equal(t, int64(1), ts)
@@ -946,7 +950,8 @@ func TestPopulateWithDelSeriesIterator_SeekWithMinTime(t *testing.T) {
 		[]tsdbutil.Sample{sample{1, 6, nil, nil}, sample{5, 6, nil, nil}, sample{6, 8, nil, nil}},
 	)
 
-	it := newPopulateWithDelGenericSeriesIterator(ulid.ULID{}, f, chkMetas, nil).toSeriesIterator()
+	it := &populateWithDelSeriesIterator{}
+	it.reset(ulid.ULID{}, f, chkMetas, nil)
 	require.Equal(t, chunkenc.ValNone, it.Seek(7))
 	require.Equal(t, chunkenc.ValFloat, it.Seek(3))
 }
@@ -958,9 +963,8 @@ func TestPopulateWithDelSeriesIterator_NextWithMinTime(t *testing.T) {
 		[]tsdbutil.Sample{sample{1, 6, nil, nil}, sample{5, 6, nil, nil}, sample{7, 8, nil, nil}},
 	)
 
-	it := newPopulateWithDelGenericSeriesIterator(
-		ulid.ULID{}, f, chkMetas, tombstones.Intervals{{Mint: math.MinInt64, Maxt: 2}}.Add(tombstones.Interval{Mint: 4, Maxt: math.MaxInt64}),
-	).toSeriesIterator()
+	it := &populateWithDelSeriesIterator{}
+	it.reset(ulid.ULID{}, f, chkMetas, tombstones.Intervals{{Mint: math.MinInt64, Maxt: 2}}.Add(tombstones.Interval{Mint: 4, Maxt: math.MaxInt64}))
 	require.Equal(t, chunkenc.ValNone, it.Next())
 }
 
@@ -2225,11 +2229,12 @@ func TestBlockBaseSeriesSet(t *testing.T) {
 
 		i := 0
 		for bcs.Next() {
-			chks := bcs.currIterFn().chks
+			si := populateWithDelGenericSeriesIterator{}
+			si.reset(bcs.blockID, bcs.chunks, bcs.curr.chks, bcs.curr.intervals)
 			idx := tc.expIdxs[i]
 
-			require.Equal(t, tc.series[idx].lset, bcs.currLabels)
-			require.Equal(t, tc.series[idx].chunks, chks)
+			require.Equal(t, tc.series[idx].lset, bcs.curr.labels)
+			require.Equal(t, tc.series[idx].chunks, si.chks)
 
 			i++
 		}