Add counter reset test for mmapped OOO chunks (#544)

* Add counter reset test for mmapped OOO chunks Fixed a couple of bugs that were discovered while writing the test: - mint for ooo chunk needed to be set when a new chunk was created - first chunk was using the wrong previous appender Signed-off-by: Fiona Liao <fiona.y.liao@gmail.com> * nolint:staticcheck --------- Signed-off-by: Fiona Liao <fiona.y.liao@gmail.com>
grafana · Jan 19, 2024 · 914c46c · 914c46c
1 parent a2cdcaa
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Showing 2 changed files with 194 additions and 2 deletions.
diff --git a/tsdb/head_test.go b/tsdb/head_test.go
@@ -4346,6 +4346,190 @@ func TestHistogramCounterResetHeader(t *testing.T) {
 	}
 }
 
+type expOOOMmappedChunks struct {
+	header     chunkenc.CounterResetHeader
+	mint, maxt int64
+	numSamples uint16
+}
+
+func TestOOOHistogramCounterResetHeaders(t *testing.T) {
+	for _, floatHisto := range []bool{true, false} {
+		t.Run(fmt.Sprintf("floatHistogram=%t", floatHisto), func(t *testing.T) {
+			l := labels.FromStrings("a", "b")
+			head, _ := newTestHead(t, 1000, wlog.CompressionNone, true)
+			head.opts.OutOfOrderCapMax.Store(5)
+
+			t.Cleanup(func() {
+				require.NoError(t, head.Close())
+			})
+			require.NoError(t, head.Init(0))
+
+			appendHistogram := func(ts int64, h *histogram.Histogram) {
+				app := head.Appender(context.Background())
+				var err error
+				if floatHisto {
+					_, err = app.AppendHistogram(0, l, ts, nil, h.ToFloat())
+				} else {
+					_, err = app.AppendHistogram(0, l, ts, h.Copy(), nil)
+				}
+				require.NoError(t, err)
+				require.NoError(t, app.Commit())
+			}
+
+			var expChunks []expOOOMmappedChunks
+			checkOOOExpCounterResetHeader := func(newChunks ...expOOOMmappedChunks) {
+				expChunks = append(expChunks, newChunks...)
+
+				ms, _, err := head.getOrCreate(l.Hash(), l)
+				require.NoError(t, err)
+
+				require.Len(t, ms.ooo.oooMmappedChunks, len(expChunks))
+
+				for i, mmapChunk := range ms.ooo.oooMmappedChunks {
+					chk, err := head.chunkDiskMapper.Chunk(mmapChunk.ref)
+					require.NoError(t, err)
+					if floatHisto {
+						require.Equal(t, expChunks[i].header, chk.(*chunkenc.FloatHistogramChunk).GetCounterResetHeader())
+					} else {
+						require.Equal(t, expChunks[i].header, chk.(*chunkenc.HistogramChunk).GetCounterResetHeader())
+					}
+					require.Equal(t, expChunks[i].mint, mmapChunk.minTime)
+					require.Equal(t, expChunks[i].maxt, mmapChunk.maxTime)
+					require.Equal(t, expChunks[i].numSamples, mmapChunk.numSamples)
+				}
+			}
+
+			h := tsdbutil.GenerateTestHistograms(1)[0]
+			h.PositiveBuckets = []int64{100, 1, 1, 1}
+			h.NegativeBuckets = []int64{100, 1, 1, 1}
+			h.Count = 1000
+
+			// Append an in-order histogram, so the rest of the samples can be detected as OOO.
+			appendHistogram(1000, h)
+
+			// OOO histogram
+			for i := 1; i <= 5; i++ {
+				h.Count = 1000 + uint64(i)
+				appendHistogram(100+int64(i), h)
+			}
+			// Nothing mmapped yet.
+			checkOOOExpCounterResetHeader()
+
+			// 6th observation (which triggers a head chunk mmapping).
+			h.Count = 1002
+			appendHistogram(int64(112), h)
+
+			// One mmapped chunk with (ts, val) [(101, 1001), (102, 1002), (103, 1003), (104, 1004), (105, 1005)].
+			checkOOOExpCounterResetHeader(expOOOMmappedChunks{
+				header:     chunkenc.UnknownCounterReset,
+				mint:       101,
+				maxt:       105,
+				numSamples: 5,
+			})
+
+			// Add more samples, there's a counter reset at ts 122.
+			h.Count = 1001
+			appendHistogram(int64(110), h)
+			h.Count = 904
+			appendHistogram(int64(124), h)
+			h.Count = 903
+			appendHistogram(int64(123), h)
+			h.Count = 902
+			appendHistogram(int64(122), h)
+
+			// New samples not mmapped yet.
+			checkOOOExpCounterResetHeader()
+
+			// 11th observation (which triggers another head chunk mmapping).
+			h.Count = 2000
+			appendHistogram(int64(200), h)
+
+			// Two new mmapped chunks [(110, 1001), (112, 1002)], [(122, 902), (123, 903), (124, 904)].
+			checkOOOExpCounterResetHeader(
+				expOOOMmappedChunks{
+					header:     chunkenc.UnknownCounterReset,
+					mint:       110,
+					maxt:       112,
+					numSamples: 2,
+				},
+				expOOOMmappedChunks{
+					header:     chunkenc.CounterReset,
+					mint:       122,
+					maxt:       124,
+					numSamples: 3,
+				},
+			)
+
+			// Count is lower than previous sample at ts 200, so the NotCounterReset is ignored.
+			h.Count = 1000
+			h.CounterResetHint = histogram.NotCounterReset
+			appendHistogram(int64(205), h)
+
+			h.Count = 2010
+			h.CounterResetHint = histogram.CounterReset
+			appendHistogram(int64(210), h)
+
+			h.Count = 2020
+			h.CounterResetHint = histogram.UnknownCounterReset
+			appendHistogram(int64(220), h)
+
+			h.Count = 2005
+			appendHistogram(int64(215), h)
+
+			// 16th observation (which triggers another head chunk mmapping).
+			h.Count = 4000
+			appendHistogram(int64(350), h)
+
+			// Four new mmapped chunks: [(200, 2000)] [(205, 1000)], [(210, 2010)], [(215, 2015), (220, 2020)]
+			checkOOOExpCounterResetHeader(
+				expOOOMmappedChunks{
+					header:     chunkenc.UnknownCounterReset,
+					mint:       200,
+					maxt:       200,
+					numSamples: 1,
+				},
+				expOOOMmappedChunks{
+					header:     chunkenc.CounterReset,
+					mint:       205,
+					maxt:       205,
+					numSamples: 1,
+				},
+				expOOOMmappedChunks{
+					header:     chunkenc.CounterReset,
+					mint:       210,
+					maxt:       210,
+					numSamples: 1,
+				},
+				expOOOMmappedChunks{
+					header:     chunkenc.CounterReset,
+					mint:       215,
+					maxt:       220,
+					numSamples: 2,
+				},
+			)
+
+			// Adding five more samples (21 in total), so another mmapped chunk is created.
+			h.CounterResetHint = histogram.CounterReset
+			h.Count = 3000
+			appendHistogram(300, h)
+
+			h.CounterResetHint = histogram.UnknownCounterReset
+			for i := 1; i <= 4; i++ {
+				h.Count = 3000 + uint64(i)
+				appendHistogram(300+int64(i), h)
+			}
+
+			// One mmapped chunk with (ts, val) [(300, 3000), (301, 3001), (302, 3002), (303, 3003), (350, 4000)].
+			checkOOOExpCounterResetHeader(expOOOMmappedChunks{
+				header:     chunkenc.CounterReset,
+				mint:       300,
+				maxt:       350,
+				numSamples: 5,
+			})
+		})
+	}
+}
+
 func TestAppendingDifferentEncodingToSameSeries(t *testing.T) {
 	dir := t.TempDir()
 	opts := DefaultOptions()

diff --git a/tsdb/ooo_head.go b/tsdb/ooo_head.go
@@ -102,6 +102,10 @@ func (o *OOOChunk) ToEncodedChunks(mint, maxt int64) (chks []memChunk, err error
 		} else if s.fh != nil {
 			encoding = chunkenc.EncFloatHistogram
 		}
+
+		// prevApp is the appender for the previous sample.
+		prevApp := app
+
 		if encoding != prevEncoding { // For the first sample, this will always be true as EncNone != EncXOR | EncHistogram | EncFloatHistogram
 			if prevEncoding != chunkenc.EncNone {
 				chks = append(chks, memChunk{chunk, cmint, cmaxt, nil})
@@ -126,7 +130,8 @@ func (o *OOOChunk) ToEncodedChunks(mint, maxt int64) (chks []memChunk, err error
 		case chunkenc.EncXOR:
 			app.Append(s.t, s.f)
 		case chunkenc.EncHistogram:
-			prevHApp, _ := app.(*chunkenc.HistogramAppender)
+			// Ignoring ok is ok, since we don't want to compare to the wrong previous appender anyway.
+			prevHApp, _ := prevApp.(*chunkenc.HistogramAppender)
 			var (
 				newChunk chunkenc.Chunk
 				recoded  bool
@@ -137,9 +142,11 @@ func (o *OOOChunk) ToEncodedChunks(mint, maxt int64) (chks []memChunk, err error
 					chks = append(chks, memChunk{chunk, cmint, cmaxt, nil})
 				}
 				chunk = newChunk
+				cmint = s.t
 			}
 		case chunkenc.EncFloatHistogram:
-			prevHApp, _ := app.(*chunkenc.FloatHistogramAppender)
+			// Ignoring ok is ok, since we don't want to compare to the wrong previous appender anyway.
+			prevHApp, _ := prevApp.(*chunkenc.FloatHistogramAppender)
 			var (
 				newChunk chunkenc.Chunk
 				recoded  bool
@@ -150,6 +157,7 @@ func (o *OOOChunk) ToEncodedChunks(mint, maxt int64) (chks []memChunk, err error
 					chks = append(chks, memChunk{chunk, cmint, cmaxt, nil})
 				}
 				chunk = newChunk
+				cmint = s.t
 			}
 		}
 		cmaxt = s.t