diff --git a/block.go b/block.go
index 3e7b5ad24..2ecc7687c 100644
--- a/block.go
+++ b/block.go
@@ -32,12 +32,12 @@ type DiskBlock interface {
 // Block is an interface to a DiskBlock that can also be queried.
 type Block interface {
 	DiskBlock
-	// Queryable
+	Queryable
 }
 
 // HeadBlock is a regular block that can still be appended to.
 type HeadBlock interface {
-	DiskBlock
+	Block
 	Appendable
 }
 
@@ -52,7 +52,7 @@ type Appendable interface {
 
 // Queryable defines an entity which provides a Querier.
 type Queryable interface {
-	Queryable() Querier
+	Querier(mint, maxt int64) Querier
 }
 
 // BlockMeta provides meta information about a block.
@@ -86,14 +86,6 @@ const (
 	flagStd  = 1
 )
 
-type persistedBlock struct {
-	dir  string
-	meta BlockMeta
-
-	chunkr *chunkReader
-	indexr *indexReader
-}
-
 type blockMeta struct {
 	Version int `json:"version"`
 
@@ -141,6 +133,14 @@ func writeMetaFile(dir string, meta *BlockMeta) error {
 	return renameFile(tmp, path)
 }
 
+type persistedBlock struct {
+	dir  string
+	meta BlockMeta
+
+	chunkr *chunkReader
+	indexr *indexReader
+}
+
 func newPersistedBlock(dir string) (*persistedBlock, error) {
 	meta, err := readMetaFile(dir)
 	if err != nil {
@@ -174,6 +174,15 @@ func (pb *persistedBlock) Close() error {
 	return merr.Err()
 }
 
+func (pb *persistedBlock) Querier(mint, maxt int64) Querier {
+	return &blockQuerier{
+		mint:   mint,
+		maxt:   maxt,
+		index:  pb.Index(),
+		chunks: pb.Chunks(),
+	}
+}
+
 func (pb *persistedBlock) Dir() string         { return pb.dir }
 func (pb *persistedBlock) Index() IndexReader  { return pb.indexr }
 func (pb *persistedBlock) Chunks() ChunkReader { return pb.chunkr }
diff --git a/db.go b/db.go
index e84a9228a..6955477cd 100644
--- a/db.go
+++ b/db.go
@@ -95,7 +95,6 @@ type DB struct {
 	// block layout.
 	mtx    sync.RWMutex
 	blocks []Block
-	// seqBlocks map[int]Block
 
 	// Mutex that must be held when modifying just the head blocks
 	// or the general layout.
@@ -270,9 +269,10 @@ func (db *DB) compact() (changes bool, err error) {
 
 	db.headmtx.RUnlock()
 
+	db.logger.Log("msg", "picked singles", "singles", fmt.Sprintf("%v", singles))
 Loop:
 	for _, h := range singles {
-		db.logger.Log("msg", "write head", "seq", h.Meta().Sequence)
+		db.logger.Log("msg", "write head", "seq", h.Meta().Sequence, "dir", h.Dir(), "ulid", h.Meta().ULID)
 
 		select {
 		case <-db.stopc:
@@ -660,7 +660,7 @@ func (db *DB) blocksForInterval(mint, maxt int64) []Block {
 
 // cut starts a new head block to append to. The completed head block
 // will still be appendable for the configured grace period.
-func (db *DB) cut(mint int64) (*headBlock, error) {
+func (db *DB) cut(mint int64) (HeadBlock, error) {
 	maxt := mint + int64(db.opts.MinBlockDuration)
 
 	dir, seq, err := nextSequenceFile(db.dir, "b-")
diff --git a/head.go b/head.go
index f801bc69c..61a131360 100644
--- a/head.go
+++ b/head.go
@@ -172,6 +172,22 @@ func (h *headBlock) Persisted() bool     { return false }
 func (h *headBlock) Index() IndexReader  { return &headIndexReader{h} }
 func (h *headBlock) Chunks() ChunkReader { return &headChunkReader{h} }
 
+func (h *headBlock) Querier(mint, maxt int64) Querier {
+	h.mtx.RLock()
+	defer h.mtx.RUnlock()
+
+	if h.closed {
+		panic(fmt.Sprintf("block %s already closed", h.dir))
+	}
+	return &blockQuerier{
+		mint:           mint,
+		maxt:           maxt,
+		index:          h.Index(),
+		chunks:         h.Chunks(),
+		postingsMapper: h.remapPostings,
+	}
+}
+
 func (h *headBlock) Appender() Appender {
 	atomic.AddUint64(&h.activeWriters, 1)
 
diff --git a/querier.go b/querier.go
index c027a8dc0..555731171 100644
--- a/querier.go
+++ b/querier.go
@@ -55,27 +55,8 @@ func (s *DB) Querier(mint, maxt int64) Querier {
 		blocks: make([]Querier, 0, len(blocks)),
 		db:     s,
 	}
-
 	for _, b := range blocks {
-		q := &blockQuerier{
-			mint:   mint,
-			maxt:   maxt,
-			index:  b.Index(),
-			chunks: b.Chunks(),
-		}
-
-		// TODO(fabxc): find nicer solution.
-		if hb, ok := b.(*headBlock); ok {
-			// TODO(fabxc): temporary refactored.
-			hb.mtx.RLock()
-			if hb.closed {
-				panic(fmt.Sprintf("block %s already closed", hb.dir))
-			}
-			hb.mtx.RUnlock()
-			q.postingsMapper = hb.remapPostings
-		}
-
-		sq.blocks = append(sq.blocks, q)
+		sq.blocks = append(sq.blocks, b.Querier(mint, maxt))
 	}
 
 	return sq