feat(blooms): compute chunks once

cmd/migrate/main.go

@@ -309,7 +309,7 @@ func (m *chunkMover) moveChunks(ctx context.Context, threadID int, syncRangeCh <
 			start := time.Now()
 			var totalBytes uint64
 			var totalChunks uint64
-			schemaGroups, fetchers, err := m.source.GetChunks(m.ctx, m.sourceUser, model.TimeFromUnixNano(sr.from), model.TimeFromUnixNano(sr.to), chunk.NewPredicate(m.matchers, nil))
+			schemaGroups, fetchers, err := m.source.GetChunks(m.ctx, m.sourceUser, model.TimeFromUnixNano(sr.from), model.TimeFromUnixNano(sr.to), chunk.NewPredicate(m.matchers, nil), nil)
 			if err != nil {
 				log.Println(threadID, "Error querying index for chunk refs:", err)
 				errCh <- err

docs/sources/shared/configuration.md

@@ -3139,6 +3139,12 @@ The `limits_config` block configures global and per-tenant limits in Loki. The v
 # CLI flag: -limits.tsdb-sharding-strategy
 [tsdb_sharding_strategy: <string> | default = "power_of_two"]
 
+# Precompute chunks for TSDB queries. This can improve query performance at the
+# cost of increased memory usage by computing chunks once during planning,
+# reducing index calls.
+# CLI flag: -querier.tsdb-precompute-chunks
+[tsdb_precompute_chunks: <boolean> | default = false]
+
 # Cardinality limit for index queries.
 # CLI flag: -store.cardinality-limit
 [cardinality_limit: <int> | default = 100000]

pkg/indexgateway/client.go

@@ -28,9 +28,7 @@ import (
 
 	"github.com/grafana/loki/v3/pkg/distributor/clientpool"
 	"github.com/grafana/loki/v3/pkg/logproto"
-	"github.com/grafana/loki/v3/pkg/logql/syntax"
 	"github.com/grafana/loki/v3/pkg/storage/stores/series/index"
-	"github.com/grafana/loki/v3/pkg/storage/stores/shipper/indexshipper/tsdb/sharding"
 	"github.com/grafana/loki/v3/pkg/util/constants"
 	"github.com/grafana/loki/v3/pkg/util/discovery"
 	util_math "github.com/grafana/loki/v3/pkg/util/math"
@@ -340,8 +338,7 @@ func (s *GatewayClient) GetShards(
 				if err != nil {
 					return errors.WithStack(err)
 				}
-				perReplicaResult.Shards = append(perReplicaResult.Shards, resp.Shards...)
-				perReplicaResult.Statistics.Merge(resp.Statistics)
+				perReplicaResult.Merge(resp)
 			}
 
 			// Since `poolDo` retries on error, we only want to set the response if we got a successful response.
@@ -355,48 +352,11 @@ func (s *GatewayClient) GetShards(
 			return errCt <= maxErrs
 		},
 	); err != nil {
-		if isUnimplementedCallError(err) {
-			return s.getShardsFromStatsFallback(ctx, in)
-		}
 		return nil, err
 	}
 	return res, nil
 }
 
-func (s *GatewayClient) getShardsFromStatsFallback(
-	ctx context.Context,
-	in *logproto.ShardsRequest,
-) (*logproto.ShardsResponse, error) {
-	userID, err := tenant.TenantID(ctx)
-	if err != nil {
-		return nil, errors.Wrap(err, "index gateway client get tenant ID")
-	}
-
-	p, err := ExtractShardRequestMatchersAndAST(in.Query)
-	if err != nil {
-		return nil, errors.Wrap(err, "failure while falling back to stats for shard calculation")
-
-	}
-
-	stats, err := s.GetStats(
-		ctx,
-		&logproto.IndexStatsRequest{
-			From:     in.From,
-			Through:  in.Through,
-			Matchers: (&syntax.MatchersExpr{Mts: p.Matchers}).String(),
-		},
-	)
-	if err != nil {
-		return nil, err
-	}
-
-	var strategy sharding.PowerOfTwoSharding
-	shards := strategy.ShardsFor(stats.Bytes, uint64(s.limits.TSDBMaxBytesPerShard(userID)))
-	return &logproto.ShardsResponse{
-		Shards: shards,
-	}, nil
-}
-
 // TODO(owen-d): this was copied from ingester_querier.go -- move it to a shared pkg
 // isUnimplementedCallError tells if the GRPC error is a gRPC error with code Unimplemented.
 func isUnimplementedCallError(err error) bool {

pkg/indexgateway/gateway.go

@@ -6,6 +6,7 @@ import (
 	"math"
 	"sort"
 	"sync"
+	"time"
 
 	"github.com/c2h5oh/datasize"
 	"github.com/go-kit/log"
@@ -31,6 +32,7 @@ import (
 	seriesindex "github.com/grafana/loki/v3/pkg/storage/stores/series/index"
 	tsdb_index "github.com/grafana/loki/v3/pkg/storage/stores/shipper/indexshipper/tsdb/index"
 	"github.com/grafana/loki/v3/pkg/storage/stores/shipper/indexshipper/tsdb/sharding"
+	util_log "github.com/grafana/loki/v3/pkg/util/log"
 	"github.com/grafana/loki/v3/pkg/util/spanlogger"
 )
 
@@ -67,19 +69,21 @@ type Gateway struct {
 	bloomQuerier BloomQuerier
 	metrics      *Metrics
 
-	cfg Config
-	log log.Logger
+	cfg    Config
+	limits Limits
+	log    log.Logger
 }
 
 // NewIndexGateway instantiates a new Index Gateway and start its services.
 //
 // In case it is configured to be in ring mode, a Basic Service wrapping the ring client is started.
 // Otherwise, it starts an Idle Service that doesn't have lifecycle hooks.
-func NewIndexGateway(cfg Config, log log.Logger, r prometheus.Registerer, indexQuerier IndexQuerier, indexClients []IndexClientWithRange, bloomQuerier BloomQuerier) (*Gateway, error) {
+func NewIndexGateway(cfg Config, limits Limits, log log.Logger, r prometheus.Registerer, indexQuerier IndexQuerier, indexClients []IndexClientWithRange, bloomQuerier BloomQuerier) (*Gateway, error) {
 	g := &Gateway{
 		indexQuerier: indexQuerier,
 		bloomQuerier: bloomQuerier,
 		cfg:          cfg,
+		limits:       limits,
 		log:          log,
 		indexClients: indexClients,
 		metrics:      NewMetrics(r),
@@ -214,7 +218,7 @@ func (g *Gateway) GetChunkRef(ctx context.Context, req *logproto.GetChunkRefRequ
 	}
 
 	predicate := chunk.NewPredicate(matchers, &req.Plan)
-	chunks, _, err := g.indexQuerier.GetChunks(ctx, instanceID, req.From, req.Through, predicate)
+	chunks, _, err := g.indexQuerier.GetChunks(ctx, instanceID, req.From, req.Through, predicate, nil)
 	if err != nil {
 		return nil, err
 	}
@@ -368,11 +372,12 @@ func (g *Gateway) GetShards(request *logproto.ShardsRequest, server logproto.Ind
 		return err
 	}
 
-	// Shards were requested, but blooms are not enabled or cannot be used due to lack of filters.
-	// That's ok; we can still return shard ranges without filtering
-	// which will be more effective than guessing power-of-2 shard ranges.
 	forSeries, ok := g.indexQuerier.HasForSeries(request.From, request.Through)
-	if g.bloomQuerier == nil || len(syntax.ExtractLineFilters(p.Plan().AST)) == 0 || !ok {
+	if !ok {
+		sp.LogKV(
+			"msg", "index does not support forSeries",
+			"action", "falling back to indexQuerier.GetShards impl",
+		)
 		shards, err := g.indexQuerier.GetShards(
 			ctx,
 			instanceID,
@@ -388,11 +393,11 @@ func (g *Gateway) GetShards(request *logproto.ShardsRequest, server logproto.Ind
 		return server.Send(shards)
 	}
 
-	return g.getShardsWithBlooms(ctx, request, server, instanceID, p, forSeries)
+	return g.boundedShards(ctx, request, server, instanceID, p, forSeries)
 }
 
-// getShardsWithBlooms is a helper function to get shards with blooms enabled.
-func (g *Gateway) getShardsWithBlooms(
+// boundedShards handles bounded shard requests, optionally using blooms and/or returning precomputed chunks.
+func (g *Gateway) boundedShards(
 	ctx context.Context,
 	req *logproto.ShardsRequest,
 	server logproto.IndexGateway_GetShardsServer,
@@ -412,12 +417,12 @@ func (g *Gateway) getShardsWithBlooms(
 	// as getting it _very_ wrong could harm some cache locality benefits on the bloom-gws by
 	// sending multiple requests to the entire keyspace).
 
-	logger := log.With(g.log, "tenant", instanceID)
+	logger := util_log.WithContext(ctx, g.log)
 	sp, ctx := opentracing.StartSpanFromContext(ctx, "indexgateway.getShardsWithBlooms")
 	defer sp.Finish()
 
 	// 1) for all bounds, get chunk refs
-	grps, _, err := g.indexQuerier.GetChunks(ctx, instanceID, req.From, req.Through, p)
+	grps, _, err := g.indexQuerier.GetChunks(ctx, instanceID, req.From, req.Through, p, nil)
 	if err != nil {
 		return err
 	}
@@ -435,11 +440,16 @@ func (g *Gateway) getShardsWithBlooms(
 		}
 	}
 
-	// 2) filter via blooms
-	filtered, err := g.bloomQuerier.FilterChunkRefs(ctx, instanceID, req.From, req.Through, refs, p.Plan())
-	if err != nil {
-		return err
+	filtered := refs
+
+	// 2) filter via blooms if enabled
+	if g.bloomQuerier != nil {
+		filtered, err = g.bloomQuerier.FilterChunkRefs(ctx, instanceID, req.From, req.Through, refs, p.Plan())
+		if err != nil {
+			return err
+		}
 	}
+
 	g.metrics.preFilterChunks.WithLabelValues(routeShards).Observe(float64(ct))
 	g.metrics.postFilterChunks.WithLabelValues(routeShards).Observe(float64(len(filtered)))
 
@@ -462,23 +472,42 @@ func (g *Gateway) getShardsWithBlooms(
 				Stats:  &logproto.IndexStatsResponse{},
 			},
 		}
+
 	} else {
-		shards, err := accumulateChunksToShards(ctx, instanceID, forSeries, req, p, filtered)
+		shards, chunkGrps, err := accumulateChunksToShards(ctx, instanceID, forSeries, req, p, filtered)
 		if err != nil {
 			return err
 		}
 		resp.Shards = shards
+
+		// If the index gateway is configured to precompute chunks, we can return the chunk groups
+		// alongside the shards, otherwise discarding them
+		if g.limits.TSDBPrecomputeChunks(instanceID) {
+			resp.ChunkGroups = chunkGrps
+		}
 	}
 
 	sp.LogKV("msg", "send shards response", "shards", len(resp.Shards))
 
+	var refCt int
+	for _, grp := range resp.ChunkGroups {
+		refCt += len(grp.Refs)
+	}
+
+	ms := syntax.MatchersExpr{Mts: p.Matchers}
 	level.Debug(logger).Log(
 		"msg", "send shards response",
 		"total_chunks", statistics.Index.TotalChunks,
 		"post_filter_chunks", statistics.Index.PostFilterChunks,
 		"shards", len(resp.Shards),
 		"query", req.Query,
 		"target_bytes_per_shard", datasize.ByteSize(req.TargetBytesPerShard).HumanReadable(),
+		"precomputed_refs", refCt,
+		"matchers", ms.String(),
+		"from", req.From.Time().String(),
+		"through", req.Through.Time().String(),
+		"length", req.Through.Time().Sub(req.From.Time()).String(),
+		"end_delta", time.Since(req.Through.Time()).String(),
 	)
 
 	// 3) build shards
@@ -525,7 +554,7 @@ func accumulateChunksToShards(
 	req *logproto.ShardsRequest,
 	p chunk.Predicate,
 	filtered []*logproto.ChunkRef,
-) ([]logproto.Shard, error) {
+) ([]logproto.Shard, []logproto.ChunkRefGroup, error) {
 	// map for looking up post-filtered chunks in O(n) while iterating the index again for sizing info
 	filteredM := make(map[model.Fingerprint][]refWithSizingInfo, 1024)
 	for _, ref := range filtered {
@@ -541,12 +570,13 @@ func accumulateChunksToShards(
 		v1.NewBounds(filtered[0].FingerprintModel(), filtered[len(filtered)-1].FingerprintModel()),
 		req.From, req.Through,
 		func(l labels.Labels, fp model.Fingerprint, chks []tsdb_index.ChunkMeta) (stop bool) {
+			mtx.Lock()
+			defer mtx.Unlock()
+
 			// check if this is a fingerprint we need
 			if _, ok := filteredM[fp]; !ok {
 				return false
 			}
-			mtx.Lock()
-			defer mtx.Unlock()
 
 			filteredChks := filteredM[fp]
 			var j int
@@ -579,7 +609,7 @@ func accumulateChunksToShards(
 		},
 		p.Matchers...,
 	); err != nil {
-		return nil, err
+		return nil, nil, err
 	}
 
 	collectedSeries := sharding.SizedFPs(sharding.SizedFPsPool.Get(len(filteredM)))
@@ -597,7 +627,21 @@ func accumulateChunksToShards(
 	}
 	sort.Sort(collectedSeries)
 
-	return collectedSeries.ShardsFor(req.TargetBytesPerShard), nil
+	shards := collectedSeries.ShardsFor(req.TargetBytesPerShard)
+	chkGrps := make([]logproto.ChunkRefGroup, 0, len(shards))
+	for _, s := range shards {
+		from := sort.Search(len(filtered), func(i int) bool {
+			return filtered[i].Fingerprint >= uint64(s.Bounds.Min)
+		})
+		through := sort.Search(len(filtered), func(i int) bool {
+			return filtered[i].Fingerprint > uint64(s.Bounds.Max)
+		})
+		chkGrps = append(chkGrps, logproto.ChunkRefGroup{
+			Refs: filtered[from:through],
+		})
+	}
+
+	return shards, chkGrps, nil
 }
 
 type refWithSizingInfo struct {

pkg/indexgateway/gateway_test.go

@@ -39,6 +39,18 @@ const (
 	valuePrefix      = "value"
 )
 
+type mockLimits struct{}
+
+func (mockLimits) IndexGatewayShardSize(_ string) int {
+	return 0
+}
+func (mockLimits) TSDBMaxBytesPerShard(_ string) int {
+	return sharding.DefaultTSDBMaxBytesPerShard
+}
+func (mockLimits) TSDBPrecomputeChunks(_ string) bool {
+	return false
+}
+
 type mockBatch struct {
 	size int
 }
@@ -233,7 +245,7 @@ func TestGateway_QueryIndex_multistore(t *testing.T) {
 			},
 		},
 	}}
-	gateway, err := NewIndexGateway(Config{}, util_log.Logger, nil, nil, indexClients, nil)
+	gateway, err := NewIndexGateway(Config{}, mockLimits{}, util_log.Logger, nil, nil, indexClients, nil)
 	require.NoError(t, err)
 
 	expectedQueries = append(expectedQueries,
@@ -258,7 +270,7 @@ func TestVolume(t *testing.T) {
 		{Name: "bar", Volume: 38},
 	}}, nil)
 
-	gateway, err := NewIndexGateway(Config{}, util_log.Logger, nil, indexQuerier, nil, nil)
+	gateway, err := NewIndexGateway(Config{}, mockLimits{}, util_log.Logger, nil, indexQuerier, nil, nil)
 	require.NoError(t, err)
 
 	ctx := user.InjectOrgID(context.Background(), "test")
@@ -532,7 +544,7 @@ func TestAccumulateChunksToShards(t *testing.T) {
 		},
 	}
 
-	shards, err := accumulateChunksToShards(
+	shards, grps, err := accumulateChunksToShards(
 		context.Background(),
 		"",
 		fsImpl(series),
@@ -543,6 +555,12 @@ func TestAccumulateChunksToShards(t *testing.T) {
 		filtered,
 	)
 
+	expectedChks := [][]*logproto.ChunkRef{
+		filtered[0:3],
+		filtered[3:6],
+		filtered[6:9],
+		filtered[9:10],
+	}
 	exp := []logproto.Shard{
 		{
 			Bounds: logproto.FPBounds{Min: 0, Max: 1},
@@ -586,6 +604,9 @@ func TestAccumulateChunksToShards(t *testing.T) {
 
 	for i := range shards {
 		require.Equal(t, exp[i], shards[i], "invalid shard at index %d", i)
+		for j := range grps[i].Refs {
+			require.Equal(t, expectedChks[i][j], grps[i].Refs[j], "invalid chunk in grp %d at index %d", i, j)
+		}
 	}
 	require.Equal(t, len(exp), len(shards))
 

pkg/indexgateway/shufflesharding.go

@@ -22,6 +22,7 @@ var (
 type Limits interface {
 	IndexGatewayShardSize(tenantID string) int
 	TSDBMaxBytesPerShard(string) int
+	TSDBPrecomputeChunks(string) bool
 }
 
 type ShardingStrategy interface {

pkg/ingester/flush_test.go

@@ -361,7 +361,7 @@ func (s *testStore) SelectSeries(_ context.Context, _ logql.SelectLogParams) ([]
 	return nil, nil
 }
 
-func (s *testStore) GetChunks(_ context.Context, _ string, _, _ model.Time, _ chunk.Predicate) ([][]chunk.Chunk, []*fetcher.Fetcher, error) {
+func (s *testStore) GetChunks(_ context.Context, _ string, _, _ model.Time, _ chunk.Predicate, _ *logproto.ChunkRefGroup) ([][]chunk.Chunk, []*fetcher.Fetcher, error) {
 	return nil, nil, nil
 }