diff --git a/tsdb/head_read.go b/tsdb/head_read.go
index 10a462392..0ad885da2 100644
--- a/tsdb/head_read.go
+++ b/tsdb/head_read.go
@@ -582,13 +582,6 @@ func (s *memSeries) oooMergedChunks(meta chunks.Meta, cdm *chunks.ChunkDiskMappe
 	return mc, nil
 }
 
-var _ chunkenc.Iterable = &mergedOOOChunks{}
-
-// mergedOOOChunks holds the list of iterables for overlapping chunks.
-type mergedOOOChunks struct {
-	chunkIterables []chunkenc.Iterable
-}
-
 func (o mergedOOOChunks) Iterator(iterator chunkenc.Iterator) chunkenc.Iterator {
 	return storage.ChainSampleIteratorFromIterables(iterator, o.chunkIterables)
 }
diff --git a/tsdb/ooo_head_read.go b/tsdb/ooo_head_read.go
index c9fe5cd58..4985ebb98 100644
--- a/tsdb/ooo_head_read.go
+++ b/tsdb/ooo_head_read.go
@@ -42,6 +42,13 @@ type OOOHeadIndexReader struct {
 	lastGarbageCollectedMmapRef chunks.ChunkDiskMapperRef
 }
 
+var _ chunkenc.Iterable = &mergedOOOChunks{}
+
+// mergedOOOChunks holds the list of iterables for overlapping chunks.
+type mergedOOOChunks struct {
+	chunkIterables []chunkenc.Iterable
+}
+
 func NewOOOHeadIndexReader(head *Head, mint, maxt int64, lastGarbageCollectedMmapRef chunks.ChunkDiskMapperRef) *OOOHeadIndexReader {
 	hr := &headIndexReader{
 		head: head,