Bring back tombstones to Head block (#6542)

* Bring back tombstones to Head block

Signed-off-by: Ganesh Vernekar <cs15btech11018@iith.ac.in>

* Add test cases

Signed-off-by: Ganesh Vernekar <cs15btech11018@iith.ac.in>

* Cleanup

Signed-off-by: Ganesh Vernekar <cs15btech11018@iith.ac.in>

tsdb/db_test.go

@@ -316,22 +316,6 @@ Outer:
 			newSeries(map[string]string{"a": "b"}, expSamples),
 		})
 
-		lns, err := q.LabelNames()
-		testutil.Ok(t, err)
-		lvs, err := q.LabelValues("a")
-		testutil.Ok(t, err)
-		if len(expSamples) == 0 {
-			testutil.Equals(t, 0, len(lns))
-			testutil.Equals(t, 0, len(lvs))
-			testutil.Assert(t, res.Next() == false, "")
-			continue
-		} else {
-			testutil.Equals(t, 1, len(lns))
-			testutil.Equals(t, 1, len(lvs))
-			testutil.Equals(t, "a", lns[0])
-			testutil.Equals(t, "b", lvs[0])
-		}
-
 		for {
 			eok, rok := expss.Next(), res.Next()
 			testutil.Equals(t, eok, rok)

tsdb/head.go

@@ -56,10 +56,6 @@ var (
 	// ErrInvalidSample is returned if an appended sample is not valid and can't
 	// be ingested.
 	ErrInvalidSample = errors.New("invalid sample")
-
-	// emptyTombstoneReader is a no-op Tombstone Reader.
-	// This is used by head to satisfy the Tombstones() function call.
-	emptyTombstoneReader = tombstones.NewMemTombstones()
 )
 
 // Head handles reads and writes of time series data within a time window.
@@ -91,6 +87,8 @@ type Head struct {
 
 	postings *index.MemPostings // postings lists for terms
 
+	tombstones *tombstones.MemTombstones
+
 	cardinalityMutex      sync.Mutex
 	cardinalityCache      *index.PostingsStats // posting stats cache which will expire after 30sec
 	lastPostingsStatsCall time.Duration        // last posting stats call (PostingsCardinalityStats()) time for caching
@@ -276,6 +274,7 @@ func NewHead(r prometheus.Registerer, l log.Logger, wal *wal.WAL, chunkRange int
 		values:     map[string]stringset{},
 		symbols:    map[string]struct{}{},
 		postings:   index.NewUnorderedMemPostings(),
+		tombstones: tombstones.NewMemTombstones(),
 		deleted:    map[uint64]int{},
 	}
 	h.metrics = newHeadMetrics(h, r)
@@ -392,14 +391,8 @@ func (h *Head) loadWAL(r *wal.Reader, multiRef map[uint64]uint64) (err error) {
 
 	var (
 		dec    record.Decoder
-		allStones = tombstones.NewMemTombstones()
 		shards = make([][]record.RefSample, n)
 	)
-	defer func() {
-		if err := allStones.Close(); err != nil {
-			level.Warn(h.logger).Log("msg", "closing  memTombstones during wal read", "err", err)
-		}
-	}()
 
 	var (
 		decoded    = make(chan interface{}, 10)
@@ -532,7 +525,7 @@ func (h *Head) loadWAL(r *wal.Reader, multiRef map[uint64]uint64) (err error) {
 						unknownRefs++
 						continue
 					}
-					allStones.AddInterval(s.Ref, itv)
+					h.tombstones.AddInterval(s.Ref, itv)
 				}
 			}
 			//lint:ignore SA6002 relax staticcheck verification.
@@ -560,12 +553,6 @@ func (h *Head) loadWAL(r *wal.Reader, multiRef map[uint64]uint64) (err error) {
 		return errors.Wrap(r.Err(), "read records")
 	}
 
-	if err := allStones.Iter(func(ref uint64, dranges tombstones.Intervals) error {
-		return h.chunkRewrite(ref, dranges)
-	}); err != nil {
-		return errors.Wrap(r.Err(), "deleting samples from tombstones")
-	}
-
 	if unknownRefs > 0 {
 		level.Warn(h.logger).Log("msg", "unknown series references", "count", unknownRefs)
 	}
@@ -772,7 +759,7 @@ func (h *rangeHead) Chunks() (ChunkReader, error) {
 }
 
 func (h *rangeHead) Tombstones() (tombstones.Reader, error) {
-	return emptyTombstoneReader, nil
+	return h.head.tombstones, nil
 }
 
 func (h *rangeHead) MinTime() int64 {
@@ -1066,7 +1053,6 @@ func (h *Head) Delete(mint, maxt int64, ms ...*labels.Matcher) error {
 	}
 
 	var stones []tombstones.Stone
-	dirty := false
 	for p.Next() {
 		series := h.series.getByID(p.At())
 
@@ -1076,59 +1062,19 @@ func (h *Head) Delete(mint, maxt int64, ms ...*labels.Matcher) error {
 		}
 		// Delete only until the current values and not beyond.
 		t0, t1 = clampInterval(mint, maxt, t0, t1)
-		if h.wal != nil {
 		stones = append(stones, tombstones.Stone{Ref: p.At(), Intervals: tombstones.Intervals{{Mint: t0, Maxt: t1}}})
 	}
-		if err := h.chunkRewrite(p.At(), tombstones.Intervals{{Mint: t0, Maxt: t1}}); err != nil {
-			return errors.Wrap(err, "delete samples")
-		}
-		dirty = true
-	}
 	if p.Err() != nil {
 		return p.Err()
 	}
-	var enc record.Encoder
 	if h.wal != nil {
-		// Although we don't store the stones in the head
+		var enc record.Encoder
-		// we need to write them to the WAL to mark these as deleted
-		// after a restart while loading the WAL.
 		if err := h.wal.Log(enc.Tombstones(stones, nil)); err != nil {
 			return err
 		}
 	}
-	if dirty {
+	for _, s := range stones {
-		h.gc()
+		h.tombstones.AddInterval(s.Ref, s.Intervals[0])
-	}
-
-	return nil
-}
-
-// chunkRewrite re-writes the chunks which overlaps with deleted ranges
-// and removes the samples in the deleted ranges.
-// Chunks is deleted if no samples are left at the end.
-func (h *Head) chunkRewrite(ref uint64, dranges tombstones.Intervals) (err error) {
-	if len(dranges) == 0 {
-		return nil
-	}
-
-	ms := h.series.getByID(ref)
-	ms.Lock()
-	defer ms.Unlock()
-	if len(ms.chunks) == 0 {
-		return nil
-	}
-
-	metas := ms.chunksMetas()
-	mint, maxt := metas[0].MinTime, metas[len(metas)-1].MaxTime
-	it := newChunkSeriesIterator(metas, dranges, mint, maxt)
-
-	ms.reset()
-	for it.Next() {
-		t, v := it.At()
-		ok, _ := ms.append(t, v)
-		if !ok {
-			level.Warn(h.logger).Log("msg", "failed to add sample during delete")
-		}
 	}
 
 	return nil
@@ -1199,7 +1145,7 @@ func (h *Head) gc() {
 
 // Tombstones returns a new reader over the head's tombstones
 func (h *Head) Tombstones() (tombstones.Reader, error) {
-	return emptyTombstoneReader, nil
+	return h.tombstones, nil
 }
 
 // Index returns an IndexReader against the block.
@@ -1748,26 +1694,6 @@ func (s *memSeries) cut(mint int64) *memChunk {
 	return c
 }
 
-func (s *memSeries) chunksMetas() []chunks.Meta {
-	metas := make([]chunks.Meta, 0, len(s.chunks))
-	for _, chk := range s.chunks {
-		metas = append(metas, chunks.Meta{Chunk: chk.chunk, MinTime: chk.minTime, MaxTime: chk.maxTime})
-	}
-	return metas
-}
-
-// reset re-initialises all the variable in the memSeries except 'lset', 'ref',
-// and 'chunkRange', like how it would appear after 'newMemSeries(...)'.
-func (s *memSeries) reset() {
-	s.chunks = nil
-	s.headChunk = nil
-	s.firstChunkID = 0
-	s.nextAt = math.MinInt64
-	s.sampleBuf = [4]sample{}
-	s.pendingCommit = false
-	s.app = nil
-}
-
 // appendable checks whether the given sample is valid for appending to the series.
 func (s *memSeries) appendable(t int64, v float64) error {
 	c := s.head()

tsdb/head_test.go

@@ -455,6 +455,7 @@ func TestHeadDeleteSimple(t *testing.T) {
 
 	cases := []struct {
 		dranges    tombstones.Intervals
+		addSamples []sample // Samples to add after delete.
 		smplsExp   []sample
 	}{
 		{
@@ -477,6 +478,18 @@ func TestHeadDeleteSimple(t *testing.T) {
 			dranges:  tombstones.Intervals{{Mint: 0, Maxt: 9}},
 			smplsExp: buildSmpls([]int64{}),
 		},
+		{
+			dranges:    tombstones.Intervals{{Mint: 1, Maxt: 3}},
+			addSamples: buildSmpls([]int64{11, 13, 15}),
+			smplsExp:   buildSmpls([]int64{0, 4, 5, 6, 7, 8, 9, 11, 13, 15}),
+		},
+		{
+			// After delete, the appended samples in the deleted range should be visible
+			// as the tombstones are clamped to head min/max time.
+			dranges:    tombstones.Intervals{{Mint: 7, Maxt: 20}},
+			addSamples: buildSmpls([]int64{11, 13, 15}),
+			smplsExp:   buildSmpls([]int64{0, 1, 2, 3, 4, 5, 6, 11, 13, 15}),
+		},
 	}
 
 	for _, compress := range []bool{false, true} {
@@ -510,6 +523,15 @@ func TestHeadDeleteSimple(t *testing.T) {
 					testutil.Ok(t, head.Delete(r.Mint, r.Maxt, labels.MustNewMatcher(labels.MatchEqual, lblDefault.Name, lblDefault.Value)))
 				}
 
+				// Add more samples.
+				app = head.Appender()
+				for _, smpl := range c.addSamples {
+					_, err = app.Add(labels.Labels{lblDefault}, smpl.t, smpl.v)
+					testutil.Ok(t, err)
+
+				}
+				testutil.Ok(t, app.Commit())
+
 				// Compare the samples for both heads - before and after the reload.
 				reloadedW, err := wal.New(nil, nil, w.Dir(), compress) // Use a new wal to ensure deleted samples are gone even after a reload.
 				testutil.Ok(t, err)
@@ -518,37 +540,6 @@ func TestHeadDeleteSimple(t *testing.T) {
 				testutil.Ok(t, err)
 				defer reloadedHead.Close()
 				testutil.Ok(t, reloadedHead.Init(0))
-				for _, h := range []*Head{head, reloadedHead} {
-					indexr, err := h.Index()
-					testutil.Ok(t, err)
-					// Use an emptyTombstoneReader explicitly to get all the samples.
-					css, err := LookupChunkSeries(indexr, emptyTombstoneReader, labels.MustNewMatcher(labels.MatchEqual, lblDefault.Name, lblDefault.Value))
-					testutil.Ok(t, err)
-
-					// Getting the actual samples.
-					actSamples := make([]sample, 0)
-					for css.Next() {
-						lblsAct, chkMetas, intv := css.At()
-						testutil.Equals(t, labels.Labels{lblDefault}, lblsAct)
-						testutil.Equals(t, 0, len(intv))
-
-						chunkr, err := h.Chunks()
-						testutil.Ok(t, err)
-						var ii chunkenc.Iterator
-						for _, meta := range chkMetas {
-							chk, err := chunkr.Chunk(meta.Ref)
-							testutil.Ok(t, err)
-							ii = chk.Iterator(ii)
-							for ii.Next() {
-								t, v := ii.At()
-								actSamples = append(actSamples, sample{t: t, v: v})
-							}
-						}
-					}
-
-					testutil.Ok(t, css.Err())
-					testutil.Equals(t, c.smplsExp, actSamples)
-				}
 
 				// Compare the query results for both heads - before and after the reload.
 				expSeriesSet := newMockSeriesSet([]Series{
@@ -567,24 +558,6 @@ func TestHeadDeleteSimple(t *testing.T) {
 					actSeriesSet, err := q.Select(labels.MustNewMatcher(labels.MatchEqual, lblDefault.Name, lblDefault.Value))
 					testutil.Ok(t, err)
 
-					lns, err := q.LabelNames()
-					testutil.Ok(t, err)
-					lvs, err := q.LabelValues(lblDefault.Name)
-					testutil.Ok(t, err)
-					// When all samples are deleted we expect that no labels should exist either.
-					if len(c.smplsExp) == 0 {
-						testutil.Equals(t, 0, len(lns))
-						testutil.Equals(t, 0, len(lvs))
-						testutil.Assert(t, actSeriesSet.Next() == false, "")
-						testutil.Ok(t, h.Close())
-						continue
-					} else {
-						testutil.Equals(t, 1, len(lns))
-						testutil.Equals(t, 1, len(lvs))
-						testutil.Equals(t, lblDefault.Name, lns[0])
-						testutil.Equals(t, lblDefault.Value, lvs[0])
-					}
-
 					for {
 						eok, rok := expSeriesSet.Next(), actSeriesSet.Next()
 						testutil.Equals(t, eok, rok)
@@ -625,12 +598,15 @@ func TestDeleteUntilCurMax(t *testing.T) {
 	testutil.Ok(t, app.Commit())
 	testutil.Ok(t, hb.Delete(0, 10000, labels.MustNewMatcher(labels.MatchEqual, "a", "b")))
 
-	// Test the series have been deleted.
+	// Test the series returns no samples. The series is cleared only after compaction.
 	q, err := NewBlockQuerier(hb, 0, 100000)
 	testutil.Ok(t, err)
 	res, err := q.Select(labels.MustNewMatcher(labels.MatchEqual, "a", "b"))
 	testutil.Ok(t, err)
-	testutil.Assert(t, !res.Next(), "series didn't get deleted")
+	testutil.Assert(t, res.Next(), "series is not present")
+	s := res.At()
+	it := s.Iterator()
+	testutil.Assert(t, !it.Next(), "expected no samples")
 
 	// Add again and test for presence.
 	app = hb.Appender()
@@ -643,7 +619,7 @@ func TestDeleteUntilCurMax(t *testing.T) {
 	testutil.Ok(t, err)
 	testutil.Assert(t, res.Next(), "series don't exist")
 	exps := res.At()
-	it := exps.Iterator()
+	it = exps.Iterator()
 	resSamples, err := expandSeriesIterator(it)
 	testutil.Ok(t, err)
 	testutil.Equals(t, []tsdbutil.Sample{sample{11, 1}}, resSamples)

tsdb/tombstones/tombstones.go

@@ -199,18 +199,18 @@ func ReadTombstones(dir string) (Reader, int64, error) {
 	return stonesMap, int64(len(b)), nil
 }
 
-type memTombstones struct {
+type MemTombstones struct {
 	intvlGroups map[uint64]Intervals
 	mtx         sync.RWMutex
 }
 
 // NewMemTombstones creates new in memory Tombstone Reader
 // that allows adding new intervals.
-func NewMemTombstones() *memTombstones {
+func NewMemTombstones() *MemTombstones {
-	return &memTombstones{intvlGroups: make(map[uint64]Intervals)}
+	return &MemTombstones{intvlGroups: make(map[uint64]Intervals)}
 }
 
-func NewTestMemTombstones(intervals []Intervals) *memTombstones {
+func NewTestMemTombstones(intervals []Intervals) *MemTombstones {
 	ret := NewMemTombstones()
 	for i, intervalsGroup := range intervals {
 		for _, interval := range intervalsGroup {
@@ -220,13 +220,13 @@ func NewTestMemTombstones(intervals []Intervals) *memTombstones {
 	return ret
 }
 
-func (t *memTombstones) Get(ref uint64) (Intervals, error) {
+func (t *MemTombstones) Get(ref uint64) (Intervals, error) {
 	t.mtx.RLock()
 	defer t.mtx.RUnlock()
 	return t.intvlGroups[ref], nil
 }
 
-func (t *memTombstones) Iter(f func(uint64, Intervals) error) error {
+func (t *MemTombstones) Iter(f func(uint64, Intervals) error) error {
 	t.mtx.RLock()
 	defer t.mtx.RUnlock()
 	for ref, ivs := range t.intvlGroups {
@@ -237,7 +237,7 @@ func (t *memTombstones) Iter(f func(uint64, Intervals) error) error {
 	return nil
 }
 
-func (t *memTombstones) Total() uint64 {
+func (t *MemTombstones) Total() uint64 {
 	t.mtx.RLock()
 	defer t.mtx.RUnlock()
 
@@ -249,7 +249,7 @@ func (t *memTombstones) Total() uint64 {
 }
 
 // AddInterval to an existing memTombstones.
-func (t *memTombstones) AddInterval(ref uint64, itvs ...Interval) {
+func (t *MemTombstones) AddInterval(ref uint64, itvs ...Interval) {
 	t.mtx.Lock()
 	defer t.mtx.Unlock()
 	for _, itv := range itvs {
@@ -257,7 +257,7 @@ func (t *memTombstones) AddInterval(ref uint64, itvs ...Interval) {
 	}
 }
 
-func (*memTombstones) Close() error {
+func (*MemTombstones) Close() error {
 	return nil
 }