From 29f476ce9c3a82724eb26868efabe8b5f6554cdf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gy=C3=B6rgy=20Krajcsovits?= <gyorgy.krajcsovits@grafana.com>
Date: Thu, 29 Aug 2024 15:27:36 +0200
Subject: [PATCH] Follow up PR 14729
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Signed-off-by: György Krajcsovits <gyorgy.krajcsovits@grafana.com>
---
 tsdb/db_test.go            |  2 ++
 tsdb/ooo_head_read.go      | 51 +-------------------------------------
 tsdb/ooo_head_read_test.go |  1 -
 3 files changed, 3 insertions(+), 51 deletions(-)

diff --git a/tsdb/db_test.go b/tsdb/db_test.go
index 82d2c7705a..69f0fb2f40 100644
--- a/tsdb/db_test.go
+++ b/tsdb/db_test.go
@@ -6749,6 +6749,7 @@ func TestOOOHistogramCompactionWithCounterResets(t *testing.T) {
 		}
 		// Counter reset.
 		s = addSample(int64(490), series1, 100000, histogram.UnknownCounterReset)
+		s = copyWithCounterReset(s, histogram.CounterReset)
 		series1ExpSamplesPreCompact = append(series1ExpSamplesPreCompact, s)
 		series1ExpSamplesPostCompact = append(series1ExpSamplesPostCompact, s)
 		// Add some more samples after the counter reset.
@@ -6773,6 +6774,7 @@ func TestOOOHistogramCompactionWithCounterResets(t *testing.T) {
 		}
 		// Counter reset.
 		s = addSample(int64(300), series2, 100000, histogram.UnknownCounterReset)
+		s = copyWithCounterReset(s, histogram.CounterReset)
 		series2ExpSamplesPreCompact = append(series2ExpSamplesPreCompact, s)
 		series2ExpSamplesPostCompact = append(series2ExpSamplesPostCompact, s)
 		// Add some more samples after the counter reset.
diff --git a/tsdb/ooo_head_read.go b/tsdb/ooo_head_read.go
index d26cec0200..1d897d5814 100644
--- a/tsdb/ooo_head_read.go
+++ b/tsdb/ooo_head_read.go
@@ -54,53 +54,6 @@ func NewHeadAndOOOIndexReader(head *Head, mint, maxt int64, lastGarbageCollected
 	return &HeadAndOOOIndexReader{hr, lastGarbageCollectedMmapRef}
 }
 
-type MultiChunk struct {
-	chunks []chunkenc.Chunk
-}
-
-func (c MultiChunk) Iterator(it chunkenc.Iterator) chunkenc.Iterator {
-	switch len(c.chunks) {
-	case 0:
-		return chunkenc.NewNopIterator()
-	case 1:
-		return c.chunks[0].Iterator(it)
-	default:
-		iterators := make([]chunkenc.Iterator, 0, len(c.chunks))
-		for _, chk := range c.chunks {
-			iterators = append(iterators, chk.Iterator(nil))
-		}
-		return storage.ChainSampleIteratorFromIterators(it, iterators)
-	}
-}
-
-func (c MultiChunk) Appender() (chunkenc.Appender, error) {
-	return nil, errors.New("not implemented")
-}
-
-func (c MultiChunk) Bytes() []byte {
-	return nil
-}
-
-func (c MultiChunk) Compact() {
-	// no-op
-}
-
-func (c MultiChunk) Encoding() chunkenc.Encoding {
-	return chunkenc.EncNone
-}
-
-func (c MultiChunk) NumSamples() int {
-	sum := 0
-	for _, chk := range c.chunks {
-		sum += chk.NumSamples()
-	}
-	return sum
-}
-
-func (c MultiChunk) Reset([]byte) {
-	// no-op
-}
-
 func (oh *HeadAndOOOIndexReader) Series(ref storage.SeriesRef, builder *labels.ScratchBuilder, chks *[]chunks.Meta) error {
 	s := oh.head.series.getByID(chunks.HeadSeriesRef(ref))
 
@@ -148,16 +101,14 @@ func getOOOSeriesChunks(s *memSeries, mint, maxt int64, lastGarbageCollectedMmap
 		if c.OverlapsClosedInterval(mint, maxt) && maxMmapRef == 0 {
 			ref := chunks.ChunkRef(chunks.NewHeadChunkRef(s.ref, s.oooHeadChunkID(len(s.ooo.oooMmappedChunks))))
 			if len(c.chunk.samples) > 0 { // Empty samples happens in tests, at least.
-				headChunks := MultiChunk{}
 				chks, err := s.ooo.oooHeadChunk.chunk.ToEncodedChunks(c.minTime, c.maxTime)
 				if err != nil {
 					handleChunkWriteError(err)
 					return nil
 				}
 				for _, chk := range chks {
-					headChunks.chunks = append(headChunks.chunks, chk.chunk)
+					addChunk(chk.minTime, chk.maxTime, ref, chk.chunk)
 				}
-				addChunk(c.minTime, c.maxTime, ref, headChunks)
 			} else {
 				var emptyChunk chunkenc.Chunk
 				addChunk(c.minTime, c.maxTime, ref, emptyChunk)
diff --git a/tsdb/ooo_head_read_test.go b/tsdb/ooo_head_read_test.go
index 581da60403..37e3fe4d37 100644
--- a/tsdb/ooo_head_read_test.go
+++ b/tsdb/ooo_head_read_test.go
@@ -33,7 +33,6 @@ import (
 
 // Type assertions.
 var (
-	_ chunkenc.Chunk    = &MultiChunk{}
 	_ chunkenc.Iterable = &mergedOOOChunks{}
 	_ IndexReader       = &HeadAndOOOIndexReader{}
 )