Add support to query unmerged, unsorted chunks (#299)

* Add support to query unmerged, unsorted chunks

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Fix unrelated lint issue

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

storage/merge.go

@@ -717,3 +717,56 @@ func (h *chunkIteratorHeap) Pop() interface{} {
 	*h = old[0 : n-1]
 	return x
 }
+
+// NewConcatenatingChunkSeriesMerger returns a VerticalChunkSeriesMergeFunc that simply concatenates the
+// chunks from the series. The resultant stream of chunks for a series might be overlapping and unsorted.
+func NewConcatenatingChunkSeriesMerger() VerticalChunkSeriesMergeFunc {
+	return func(series ...ChunkSeries) ChunkSeries {
+		if len(series) == 0 {
+			return nil
+		}
+		return &ChunkSeriesEntry{
+			Lset: series[0].Labels(),
+			ChunkIteratorFn: func() chunks.Iterator {
+				iterators := make([]chunks.Iterator, 0, len(series))
+				for _, s := range series {
+					iterators = append(iterators, s.Iterator())
+				}
+				return &concatenatingChunkIterator{
+					iterators: iterators,
+				}
+			},
+		}
+	}
+}
+
+type concatenatingChunkIterator struct {
+	iterators []chunks.Iterator
+	idx       int
+
+	curr chunks.Meta
+}
+
+func (c *concatenatingChunkIterator) At() chunks.Meta {
+	return c.curr
+}
+
+func (c *concatenatingChunkIterator) Next() bool {
+	if c.idx >= len(c.iterators) {
+		return false
+	}
+	if c.iterators[c.idx].Next() {
+		c.curr = c.iterators[c.idx].At()
+		return true
+	}
+	c.idx++
+	return c.Next()
+}
+
+func (c *concatenatingChunkIterator) Err() error {
+	errs := tsdb_errors.NewMulti()
+	for _, iter := range c.iterators {
+		errs.Add(iter.Err())
+	}
+	return errs.Err()
+}

storage/merge_test.go

@@ -499,6 +499,140 @@ func TestCompactingChunkSeriesMerger(t *testing.T) {
 	}
 }
 
+func TestConcatenatingChunkSeriesMerger(t *testing.T) {
+	m := NewConcatenatingChunkSeriesMerger()
+
+	for _, tc := range []struct {
+		name     string
+		input    []ChunkSeries
+		expected ChunkSeries
+	}{
+		{
+			name: "single empty series",
+			input: []ChunkSeries{
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), nil),
+			},
+			expected: NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), nil),
+		},
+		{
+			name: "single series",
+			input: []ChunkSeries{
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), []tsdbutil.Sample{sample{1, 1}, sample{2, 2}}, []tsdbutil.Sample{sample{3, 3}}),
+			},
+			expected: NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), []tsdbutil.Sample{sample{1, 1}, sample{2, 2}}, []tsdbutil.Sample{sample{3, 3}}),
+		},
+		{
+			name: "two empty series",
+			input: []ChunkSeries{
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), nil),
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), nil),
+			},
+			expected: NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), nil, nil),
+		},
+		{
+			name: "two non overlapping",
+			input: []ChunkSeries{
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), []tsdbutil.Sample{sample{1, 1}, sample{2, 2}}, []tsdbutil.Sample{sample{3, 3}, sample{5, 5}}),
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), []tsdbutil.Sample{sample{7, 7}, sample{9, 9}}, []tsdbutil.Sample{sample{10, 10}}),
+			},
+			expected: NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), []tsdbutil.Sample{sample{1, 1}, sample{2, 2}}, []tsdbutil.Sample{sample{3, 3}, sample{5, 5}}, []tsdbutil.Sample{sample{7, 7}, sample{9, 9}}, []tsdbutil.Sample{sample{10, 10}}),
+		},
+		{
+			name: "two overlapping",
+			input: []ChunkSeries{
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), []tsdbutil.Sample{sample{1, 1}, sample{2, 2}}, []tsdbutil.Sample{sample{3, 3}, sample{8, 8}}),
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), []tsdbutil.Sample{sample{7, 7}, sample{9, 9}}, []tsdbutil.Sample{sample{10, 10}}),
+			},
+			expected: NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"),
+				[]tsdbutil.Sample{sample{1, 1}, sample{2, 2}}, []tsdbutil.Sample{sample{3, 3}, sample{8, 8}},
+				[]tsdbutil.Sample{sample{7, 7}, sample{9, 9}}, []tsdbutil.Sample{sample{10, 10}},
+			),
+		},
+		{
+			name: "two duplicated",
+			input: []ChunkSeries{
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), []tsdbutil.Sample{sample{1, 1}, sample{2, 2}, sample{3, 3}, sample{5, 5}}),
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), []tsdbutil.Sample{sample{2, 2}, sample{3, 3}, sample{5, 5}}),
+			},
+			expected: NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"),
+				[]tsdbutil.Sample{sample{1, 1}, sample{2, 2}, sample{3, 3}, sample{5, 5}},
+				[]tsdbutil.Sample{sample{2, 2}, sample{3, 3}, sample{5, 5}},
+			),
+		},
+		{
+			name: "three overlapping",
+			input: []ChunkSeries{
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), []tsdbutil.Sample{sample{1, 1}, sample{2, 2}, sample{3, 3}, sample{5, 5}}),
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), []tsdbutil.Sample{sample{2, 2}, sample{3, 3}, sample{6, 6}}),
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), []tsdbutil.Sample{sample{0, 0}, sample{4, 4}}),
+			},
+			expected: NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"),
+				[]tsdbutil.Sample{sample{1, 1}, sample{2, 2}, sample{3, 3}, sample{5, 5}},
+				[]tsdbutil.Sample{sample{2, 2}, sample{3, 3}, sample{6, 6}},
+				[]tsdbutil.Sample{sample{0, 0}, sample{4, 4}},
+			),
+		},
+		{
+			name: "three in chained overlap",
+			input: []ChunkSeries{
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), []tsdbutil.Sample{sample{1, 1}, sample{2, 2}, sample{3, 3}, sample{5, 5}}),
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), []tsdbutil.Sample{sample{4, 4}, sample{6, 66}}),
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), []tsdbutil.Sample{sample{6, 6}, sample{10, 10}}),
+			},
+			expected: NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"),
+				[]tsdbutil.Sample{sample{1, 1}, sample{2, 2}, sample{3, 3}, sample{5, 5}},
+				[]tsdbutil.Sample{sample{4, 4}, sample{6, 66}},
+				[]tsdbutil.Sample{sample{6, 6}, sample{10, 10}},
+			),
+		},
+		{
+			name: "three in chained overlap complex",
+			input: []ChunkSeries{
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), []tsdbutil.Sample{sample{0, 0}, sample{5, 5}}, []tsdbutil.Sample{sample{10, 10}, sample{15, 15}}),
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), []tsdbutil.Sample{sample{2, 2}, sample{20, 20}}, []tsdbutil.Sample{sample{25, 25}, sample{30, 30}}),
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), []tsdbutil.Sample{sample{18, 18}, sample{26, 26}}, []tsdbutil.Sample{sample{31, 31}, sample{35, 35}}),
+			},
+			expected: NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"),
+				[]tsdbutil.Sample{sample{0, 0}, sample{5, 5}}, []tsdbutil.Sample{sample{10, 10}, sample{15, 15}},
+				[]tsdbutil.Sample{sample{2, 2}, sample{20, 20}}, []tsdbutil.Sample{sample{25, 25}, sample{30, 30}},
+				[]tsdbutil.Sample{sample{18, 18}, sample{26, 26}}, []tsdbutil.Sample{sample{31, 31}, sample{35, 35}},
+			),
+		},
+		{
+			name: "110 overlapping",
+			input: []ChunkSeries{
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), tsdbutil.GenerateSamples(0, 110)), // [0 - 110)
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), tsdbutil.GenerateSamples(60, 50)), // [60 - 110)
+			},
+			expected: NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"),
+				tsdbutil.GenerateSamples(0, 110),
+				tsdbutil.GenerateSamples(60, 50),
+			),
+		},
+		{
+			name: "150 overlapping samples, simply concatenated and no splits",
+			input: []ChunkSeries{
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), tsdbutil.GenerateSamples(0, 90)),  // [0 - 90)
+				NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"), tsdbutil.GenerateSamples(60, 90)), // [90 - 150)
+			},
+			expected: NewListChunkSeriesFromSamples(labels.FromStrings("bar", "baz"),
+				tsdbutil.GenerateSamples(0, 90),
+				tsdbutil.GenerateSamples(60, 90),
+			),
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			merged := m(tc.input...)
+			require.Equal(t, tc.expected.Labels(), merged.Labels())
+			actChks, actErr := ExpandChunks(merged.Iterator())
+			expChks, expErr := ExpandChunks(tc.expected.Iterator())
+
+			require.Equal(t, expErr, actErr)
+			require.Equal(t, expChks, actChks)
+		})
+	}
+}
+
 type mockQuerier struct {
 	LabelQuerier
 

tsdb/blockwriter.go

@@ -39,7 +39,7 @@ type BlockWriter struct {
 }
 
 // ErrNoSeriesAppended is returned if the series count is zero while flushing blocks.
-var ErrNoSeriesAppended error = errors.New("no series appended, aborting")
+var ErrNoSeriesAppended = errors.New("no series appended, aborting")
 
 // NewBlockWriter create a new block writer.
 //

tsdb/db.go

@@ -1817,8 +1817,9 @@ func (db *DB) Querier(_ context.Context, mint, maxt int64) (storage.Querier, err
 	return storage.NewMergeQuerier(blockQueriers, nil, storage.ChainedSeriesMerge), nil
 }
 
-// ChunkQuerier returns a new chunk querier over the data partition for the given time range.
+// blockQueriersForRange returns individual block chunk queriers from the persistent blocks, in-order head block, and the
-func (db *DB) ChunkQuerier(_ context.Context, mint, maxt int64) (storage.ChunkQuerier, error) {
+// out-of-order head block, overlapping with the given time range.
+func (db *DB) blockChunkQuerierForRange(mint, maxt int64) ([]storage.ChunkQuerier, error) {
 	var blocks []BlockReader
 
 	db.mtx.RLock()
@@ -1888,9 +1889,28 @@ func (db *DB) ChunkQuerier(_ context.Context, mint, maxt int64) (storage.ChunkQu
 		blockQueriers = append(blockQueriers, outOfOrderHeadQuerier)
 	}
 
+	return blockQueriers, nil
+}
+
+// ChunkQuerier returns a new chunk querier over the data partition for the given time range.
+func (db *DB) ChunkQuerier(_ context.Context, mint, maxt int64) (storage.ChunkQuerier, error) {
+	blockQueriers, err := db.blockChunkQuerierForRange(mint, maxt)
+	if err != nil {
+		return nil, err
+	}
 	return storage.NewMergeChunkQuerier(blockQueriers, nil, storage.NewCompactingChunkSeriesMerger(storage.ChainedSeriesMerge)), nil
 }
 
+// UnorderedChunkQuerier returns a new chunk querier over the data partition for the given time range.
+// The chunks can be overlapping and not sorted.
+func (db *DB) UnorderedChunkQuerier(_ context.Context, mint, maxt int64) (storage.ChunkQuerier, error) {
+	blockQueriers, err := db.blockChunkQuerierForRange(mint, maxt)
+	if err != nil {
+		return nil, err
+	}
+	return storage.NewMergeChunkQuerier(blockQueriers, nil, storage.NewConcatenatingChunkSeriesMerger()), nil
+}
+
 func (db *DB) ExemplarQuerier(ctx context.Context) (storage.ExemplarQuerier, error) {
 	return db.head.exemplars.ExemplarQuerier(ctx)
 }