diff --git a/tsdb/block.go b/tsdb/block.go
index e302ce8fa1..fa8e896e3b 100644
--- a/tsdb/block.go
+++ b/tsdb/block.go
@@ -112,7 +112,7 @@ type ChunkReader interface {
 // BlockReader provides reading access to a data block.
 type BlockReader interface {
 	// Index returns an IndexReader over the block's data.
-	Index() (IndexReader, error)
+	Index(mint, maxt int64) (IndexReader, error)
 
 	// Chunks returns a ChunkReader over the block's data.
 	Chunks() (ChunkReader, error)
@@ -372,7 +372,7 @@ func (pb *Block) startRead() error {
 }
 
 // Index returns a new IndexReader against the block data.
-func (pb *Block) Index() (IndexReader, error) {
+func (pb *Block) Index(mint, maxt int64) (IndexReader, error) {
 	if err := pb.startRead(); err != nil {
 		return nil, err
 	}
diff --git a/tsdb/compact.go b/tsdb/compact.go
index 2d7376e1af..f0cf28d9b4 100644
--- a/tsdb/compact.go
+++ b/tsdb/compact.go
@@ -683,7 +683,7 @@ func (c *LeveledCompactor) populateBlock(blocks []BlockReader, meta *BlockMeta,
 			}
 		}
 
-		indexr, err := b.Index()
+		indexr, err := b.Index(math.MinInt64, math.MaxInt64)
 		if err != nil {
 			return errors.Wrapf(err, "open index reader for block %s", b)
 		}
diff --git a/tsdb/head.go b/tsdb/head.go
index abf356e1ac..a727eef99c 100644
--- a/tsdb/head.go
+++ b/tsdb/head.go
@@ -763,7 +763,7 @@ func NewRangeHead(head *Head, mint, maxt int64) *RangeHead {
 	}
 }
 
-func (h *RangeHead) Index() (IndexReader, error) {
+func (h *RangeHead) Index(mint, maxt int64) (IndexReader, error) {
 	return h.head.indexRange(h.mint, h.maxt), nil
 }
 
@@ -1162,8 +1162,8 @@ func (h *Head) Tombstones() (tombstones.Reader, error) {
 }
 
 // Index returns an IndexReader against the block.
-func (h *Head) Index() (IndexReader, error) {
-	return h.indexRange(math.MinInt64, math.MaxInt64), nil
+func (h *Head) Index(mint, maxt int64) (IndexReader, error) {
+	return h.indexRange(mint, maxt), nil
 }
 
 func (h *Head) indexRange(mint, maxt int64) *headIndexReader {
@@ -1349,7 +1349,25 @@ func (h *headIndexReader) LabelNames() ([]string, error) {
 func (h *headIndexReader) Postings(name string, values ...string) (index.Postings, error) {
 	res := make([]index.Postings, 0, len(values))
 	for _, value := range values {
-		res = append(res, h.head.postings.Get(name, value))
+		p := h.head.postings.Get(name, value)
+		// Filter out series not in the time range, to avoid
+		// later on building up all the chunk metadata just to
+		// discard it.
+		filtered := []uint64{}
+		for p.Next() {
+			s := h.head.series.getByID(p.At())
+			if s == nil {
+				level.Debug(h.head.logger).Log("msg", "looked up series not found")
+				continue
+			}
+			if s.minTime() <= h.maxt && s.maxTime() >= h.mint {
+				filtered = append(filtered, p.At())
+			}
+		}
+		if p.Err() != nil {
+			return nil, p.Err()
+		}
+		res = append(res, index.NewListPostings(filtered))
 	}
 	return index.Merge(res...), nil
 }
diff --git a/tsdb/head_bench_test.go b/tsdb/head_bench_test.go
index c1ada34171..954541395a 100644
--- a/tsdb/head_bench_test.go
+++ b/tsdb/head_bench_test.go
@@ -14,6 +14,7 @@
 package tsdb
 
 import (
+	"fmt"
 	"strconv"
 	"sync/atomic"
 	"testing"
@@ -48,3 +49,35 @@ func BenchmarkHeadStripeSeriesCreateParallel(b *testing.B) {
 		}
 	})
 }
+
+func BenchmarkHeadSeries(b *testing.B) {
+	h, err := NewHead(nil, nil, nil, 1000)
+	testutil.Ok(b, err)
+	defer h.Close()
+	app := h.Appender()
+	numSeries := 1000000
+	for i := 0; i < numSeries; i++ {
+		app.Add(labels.FromStrings("foo", "bar", "i", strconv.Itoa(i)), int64(i), 0)
+	}
+	testutil.Ok(b, app.Commit())
+
+	matcher := labels.MustNewMatcher(labels.MatchEqual, "foo", "bar")
+
+	for s := 1; s <= numSeries; s *= 10 {
+		b.Run(fmt.Sprintf("%dof%d", s, numSeries), func(b *testing.B) {
+			q, err := NewBlockQuerier(h, 0, int64(s-1))
+			testutil.Ok(b, err)
+
+			b.ResetTimer()
+			for i := 0; i < b.N; i++ {
+				ss, err := q.Select(matcher)
+				testutil.Ok(b, err)
+				for ss.Next() {
+				}
+				testutil.Ok(b, ss.Err())
+			}
+			q.Close()
+		})
+
+	}
+}
diff --git a/tsdb/querier.go b/tsdb/querier.go
index ed5f7351cb..a5181c3f69 100644
--- a/tsdb/querier.go
+++ b/tsdb/querier.go
@@ -160,7 +160,7 @@ func (q *verticalQuerier) sel(p *storage.SelectParams, qs []storage.Querier, ms
 
 // NewBlockQuerier returns a querier against the reader.
 func NewBlockQuerier(b BlockReader, mint, maxt int64) (storage.Querier, error) {
-	indexr, err := b.Index()
+	indexr, err := b.Index(mint, maxt)
 	if err != nil {
 		return nil, errors.Wrapf(err, "open index reader")
 	}