Function TestHeadDetectsDuplicateSampleAtSizeLimit

tsdb/head_test.go:6897–6935

TestHeadDetectsDuplicateSampleAtSizeLimit tests a regression where a duplicate sample is appended to the head, right when the head chunk is at the size limit. The test adds all samples as duplicate, thus expecting that the result has exactly half of the samples.

(t *testing.T)

// The test adds all samples as duplicate, thus expecting that the result has
// exactly half of the samples.
func TestHeadDetectsDuplicateSampleAtSizeLimit(t *testing.T) {
	numSamples := 1000
	baseTS := int64(1695209650)

	h, _ := newTestHead(t, DefaultBlockDuration, compression.None, false)

	a := h.Appender(context.Background())
	var err error
	vals := []float64{math.MaxFloat64, 0x00} // Use the worst case scenario for the XOR encoding. Otherwise we hit the sample limit before the size limit.
	for i := range numSamples {
		ts := baseTS + int64(i/2)*10000
		a.Append(0, labels.FromStrings("foo", "bar"), ts, vals[(i/2)%len(vals)])
		err = a.Commit()
		require.NoError(t, err)
		a = h.Appender(context.Background())
	}

	indexReader, err := h.Index()
	require.NoError(t, err)

	var (
		chunks  []chunks.Meta
		builder labels.ScratchBuilder
	)
	require.NoError(t, indexReader.Series(1, &builder, &chunks))

	chunkReader, err := h.Chunks()
	require.NoError(t, err)

	storedSampleCount := 0
	for _, chunkMeta := range chunks {
		chunk, iterable, err := chunkReader.ChunkOrIterable(chunkMeta)
		require.NoError(t, err)
		require.Nil(t, iterable)
		storedSampleCount += chunk.NumSamples()
	}

	require.Equal(t, numSamples/2, storedSampleCount)
}

func TestWALSampleAndExemplarOrder(t *testing.T) {
	lbls := labels.FromStrings("foo", "bar")