diff --git a/Gopkg.lock b/Gopkg.lock
index 94d9dfb1be6..57e6d89a262 100644
--- a/Gopkg.lock
+++ b/Gopkg.lock
@@ -199,12 +199,12 @@
   revision = "2e65f85255dbc3072edf28d6b5b8efc472979f5a"
 
 [[projects]]
-  branch = "master"
-  digest = "1:9abc49f39e3e23e262594bb4fb70abf74c0c99e94f99153f43b143805e850719"
+  digest = "1:cea4aa2038169ee558bf507d5ea02c94ca85bcca28a4c7bb99fd59b31e43a686"
   name = "github.com/google/go-querystring"
   packages = ["query"]
   pruneopts = ""
-  revision = "53e6ce116135b80d037921a7fdd5138cf32d7a8a"
+  revision = "44c6ddd0a2342c386950e880b658017258da92fc"
+  version = "v1.0.0"
 
 [[projects]]
   digest = "1:e097a364f4e8d8d91b9b9eeafb992d3796a41fde3eb548c1a87eb9d9f60725cf"
@@ -335,12 +335,12 @@
   version = "v0.3.0"
 
 [[projects]]
-  digest = "1:82b912465c1da0668582a7d1117339c278e786c2536b3c3623029a0c7141c2d0"
+  digest = "1:84c28d9899cc4e00c38042d345cea8819275a5a62403a58530cac67022894776"
   name = "github.com/mattn/go-runewidth"
   packages = ["."]
   pruneopts = ""
-  revision = "ce7b0b5c7b45a81508558cd1dba6bb1e4ddb51bb"
-  version = "v0.0.3"
+  revision = "3ee7d812e62a0804a7d0a324e0249ca2db3476d3"
+  version = "v0.0.4"
 
 [[projects]]
   digest = "1:49a8b01a6cd6558d504b65608214ca40a78000e1b343ed0da5c6a9ccd83d6d30"
@@ -390,20 +390,12 @@
   version = "v0.11.0"
 
 [[projects]]
-  digest = "1:912349f5cf927bf96dca709623631ace7db723f07c70c4d56cfc22d9a667ed16"
+  digest = "1:b09858acd58e0873236c7b96903e3ec4e238d5de644c08bd8e712fa2d3d51ad2"
   name = "github.com/mozillazg/go-httpheader"
   packages = ["."]
   pruneopts = ""
-  revision = "4e5d6424981844faafc4b0649036b2e0395bdf99"
-  version = "v0.2.0"
-
-[[projects]]
-  branch = "master"
-  digest = "1:3adc46876d4d0e4d5bbcfcc44c2116b95d7a5c966e2ee92a219488547fd453f2"
-  name = "github.com/nightlyone/lockfile"
-  packages = ["."]
-  pruneopts = ""
-  revision = "0ad87eef1443f64d3d8c50da647e2b1552851124"
+  revision = "61f2392c3317b60616c9dcb10d0a4cfef131fe62"
+  version = "v0.2.1"
 
 [[projects]]
   digest = "1:94e9081cc450d2cdf4e6886fc2c06c07272f86477df2d74ee5931951fa3d2577"
@@ -508,11 +500,12 @@
   revision = "05ee40e3a273f7245e8777337fc7b46e533a9a92"
 
 [[projects]]
-  digest = "1:b5ff9852eabe841003da4b0a4b742a2878c722dda6481003432344f633a814fc"
+  digest = "1:912a82611430bfd1e597e76aac99cac6fd34094a07b07d7c5996cf51a21e7e07"
   name = "github.com/prometheus/prometheus"
   packages = [
     "discovery/file",
     "discovery/targetgroup",
+    "pkg/gate",
     "pkg/labels",
     "pkg/rulefmt",
     "pkg/textparse",
@@ -528,11 +521,10 @@
     "util/testutil",
   ]
   pruneopts = ""
-  revision = "71af5e29e815795e9dd14742ee7725682fa14b7b"
-  version = "v2.3.2"
+  revision = "6e08029b56ae17c49e133d92a2792f6f119f2cbd"
 
 [[projects]]
-  digest = "1:216dcf26fbfb3f36f286ca3306882a157c51648e4b5d4f3a9e9c719faea6ea58"
+  digest = "1:0a03b362c09b1186dd53330881430c7c2c26ba07806ebad861f2aa99d9c5c6ae"
   name = "github.com/prometheus/tsdb"
   packages = [
     ".",
@@ -541,9 +533,11 @@
     "fileutil",
     "index",
     "labels",
+    "wal",
   ]
   pruneopts = ""
-  revision = "bd832fc8274e8fe63999ac749daaaff9d881241f"
+  revision = "fd04e0963c04a1fbd891be7552b50f58e357f75c"
+  source = "github.com/bwplotka/tsdb"
 
 [[projects]]
   branch = "master"
diff --git a/Gopkg.toml b/Gopkg.toml
index 98bbc9494dc..e639afa84d9 100644
--- a/Gopkg.toml
+++ b/Gopkg.toml
@@ -37,7 +37,8 @@ ignored = ["github.com/improbable-eng/thanos/benchmark/*"]
   name = "github.com/prometheus/common"
 
 [[constraint]]
-  version = "v2.3.2"
+  # TODO(bwplotka): Move to released version once our recent fixes will be merged & released.
+  revision = "6e08029b56ae17c49e133d92a2792f6f119f2cbd"
   name = "github.com/prometheus/prometheus"
 
 [[override]]
@@ -46,7 +47,9 @@ ignored = ["github.com/improbable-eng/thanos/benchmark/*"]
 
 [[constraint]]
   name = "github.com/prometheus/tsdb"
-  revision = "bd832fc8274e8fe63999ac749daaaff9d881241f"
+  # TODO(bwplotka): Move to upstream version once https://github.com/prometheus/tsdb/pull/492 is merged.
+  revision = "fd04e0963c04a1fbd891be7552b50f58e357f75c"
+  source = "github.com/bwplotka/tsdb"
 
 [[constraint]]
   branch = "master"
diff --git a/cmd/thanos/bucket.go b/cmd/thanos/bucket.go
index 01b9b54bf68..eca845231bf 100644
--- a/cmd/thanos/bucket.go
+++ b/cmd/thanos/bucket.go
@@ -10,10 +10,9 @@ import (
 	"text/template"
 	"time"
 
-	"github.com/prometheus/tsdb/labels"
-
 	"github.com/go-kit/kit/log"
 	"github.com/improbable-eng/thanos/pkg/block"
+	"github.com/improbable-eng/thanos/pkg/block/blockmeta"
 	"github.com/improbable-eng/thanos/pkg/objstore/client"
 	"github.com/improbable-eng/thanos/pkg/runutil"
 	"github.com/improbable-eng/thanos/pkg/verifier"
@@ -23,6 +22,7 @@ import (
 	"github.com/opentracing/opentracing-go"
 	"github.com/pkg/errors"
 	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/tsdb/labels"
 	"golang.org/x/text/language"
 	"golang.org/x/text/message"
 	"gopkg.in/alecthomas/kingpin.v2"
@@ -254,7 +254,7 @@ func registerBucket(m map[string]setupFunc, app *kingpin.Application, name strin
 		defer cancel()
 
 		// Getting Metas.
-		var blockMetas []*block.Meta
+		var blockMetas []*blockmeta.Meta
 		if err = bkt.Iter(ctx, "", func(name string) error {
 			id, ok := block.IsBlockDir(name)
 			if !ok {
@@ -277,7 +277,7 @@ func registerBucket(m map[string]setupFunc, app *kingpin.Application, name strin
 	}
 }
 
-func printTable(blockMetas []*block.Meta, selectorLabels labels.Labels, sortBy []string) error {
+func printTable(blockMetas []*blockmeta.Meta, selectorLabels labels.Labels, sortBy []string) error {
 	header := inspectColumns
 
 	var lines [][]string
@@ -355,7 +355,7 @@ func getKeysAlphabetically(labels map[string]string) []string {
 
 // matchesSelector checks if blockMeta contains every label from
 // the selector with the correct value
-func matchesSelector(blockMeta *block.Meta, selectorLabels labels.Labels) bool {
+func matchesSelector(blockMeta *blockmeta.Meta, selectorLabels labels.Labels) bool {
 	for _, l := range selectorLabels {
 		if v, ok := blockMeta.Thanos.Labels[l.Name]; !ok || v != l.Value {
 			return false
diff --git a/cmd/thanos/downsample.go b/cmd/thanos/downsample.go
index c00aadd43db..dddd1e91afb 100644
--- a/cmd/thanos/downsample.go
+++ b/cmd/thanos/downsample.go
@@ -8,11 +8,10 @@ import (
 	"path/filepath"
 	"time"
 
-	"github.com/prometheus/tsdb/chunkenc"
-
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
 	"github.com/improbable-eng/thanos/pkg/block"
+	"github.com/improbable-eng/thanos/pkg/block/blockmeta"
 	"github.com/improbable-eng/thanos/pkg/compact/downsample"
 	"github.com/improbable-eng/thanos/pkg/objstore"
 	"github.com/improbable-eng/thanos/pkg/objstore/client"
@@ -23,6 +22,7 @@ import (
 	"github.com/pkg/errors"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/tsdb"
+	"github.com/prometheus/tsdb/chunkenc"
 	"gopkg.in/alecthomas/kingpin.v2"
 )
 
@@ -105,7 +105,7 @@ func downsampleBucket(
 	if err := os.MkdirAll(dir, 0777); err != nil {
 		return errors.Wrap(err, "create dir")
 	}
-	var metas []*block.Meta
+	var metas []*blockmeta.Meta
 
 	err := bkt.Iter(ctx, "", func(name string) error {
 		id, ok := block.IsBlockDir(name)
@@ -119,7 +119,7 @@ func downsampleBucket(
 		}
 		defer runutil.CloseWithLogOnErr(logger, rc, "block reader")
 
-		var m block.Meta
+		var m blockmeta.Meta
 		if err := json.NewDecoder(rc).Decode(&m); err != nil {
 			return errors.Wrap(err, "decode meta")
 		}
@@ -201,7 +201,7 @@ func downsampleBucket(
 	return nil
 }
 
-func processDownsampling(ctx context.Context, logger log.Logger, bkt objstore.Bucket, m *block.Meta, dir string, resolution int64) error {
+func processDownsampling(ctx context.Context, logger log.Logger, bkt objstore.Bucket, m *blockmeta.Meta, dir string, resolution int64) error {
 	begin := time.Now()
 	bdir := filepath.Join(dir, m.ULID.String())
 
diff --git a/cmd/thanos/query.go b/cmd/thanos/query.go
index bf6cfa64fe8..9e6c5ac19ef 100644
--- a/cmd/thanos/query.go
+++ b/cmd/thanos/query.go
@@ -296,7 +296,16 @@ func runQuery(
 			return stores.Get(), nil
 		}, selectorLset)
 		queryableCreator = query.NewQueryableCreator(logger, proxy, replicaLabel)
-		engine           = promql.NewEngine(logger, reg, maxConcurrentQueries, queryTimeout)
+		engine           = promql.NewEngine(
+			promql.EngineOpts{
+				Logger:        logger,
+				Reg:           reg,
+				MaxConcurrent: maxConcurrentQueries,
+				// TODO(bwplotka): Expose this as a flag: https://github.com/improbable-eng/thanos/issues/703
+				MaxSamples: math.MaxInt32,
+				Timeout:    queryTimeout,
+			},
+		)
 	)
 	// Periodically update the store set with the addresses we see in our cluster.
 	{
diff --git a/cmd/thanos/rule.go b/cmd/thanos/rule.go
index 03fed102d2e..35d81858c17 100644
--- a/cmd/thanos/rule.go
+++ b/cmd/thanos/rule.go
@@ -19,15 +19,14 @@ import (
 	"syscall"
 	"time"
 
-	"github.com/improbable-eng/thanos/pkg/extprom"
-
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
 	"github.com/improbable-eng/thanos/pkg/alert"
-	"github.com/improbable-eng/thanos/pkg/block"
+	"github.com/improbable-eng/thanos/pkg/block/blockmeta"
 	"github.com/improbable-eng/thanos/pkg/cluster"
 	"github.com/improbable-eng/thanos/pkg/discovery/cache"
 	"github.com/improbable-eng/thanos/pkg/discovery/dns"
+	"github.com/improbable-eng/thanos/pkg/extprom"
 	"github.com/improbable-eng/thanos/pkg/objstore/client"
 	"github.com/improbable-eng/thanos/pkg/runutil"
 	"github.com/improbable-eng/thanos/pkg/shipper"
@@ -290,7 +289,7 @@ func runRule(
 		ctx, cancel := context.WithCancel(context.Background())
 		ctx = tracing.ContextWithTracer(ctx, tracer)
 
-		notify := func(ctx context.Context, expr string, alerts ...*rules.Alert) error {
+		notify := func(ctx context.Context, expr string, alerts ...*rules.Alert) {
 			res := make([]*alert.Alert, 0, len(alerts))
 			for _, alrt := range alerts {
 				// Only send actually firing alerts.
@@ -309,8 +308,6 @@ func runRule(
 				res = append(res, a)
 			}
 			alertQ.Push(res)
-
-			return nil
 		}
 		mgr = rules.NewManager(&rules.ManagerOptions{
 			Context:     ctx,
@@ -579,7 +576,7 @@ func runRule(
 			}
 		}()
 
-		s := shipper.New(logger, nil, dataDir, bkt, func() labels.Labels { return lset }, block.RulerSource)
+		s := shipper.New(logger, nil, dataDir, bkt, func() labels.Labels { return lset }, blockmeta.RulerSource)
 
 		ctx, cancel := context.WithCancel(context.Background())
 
diff --git a/cmd/thanos/sidecar.go b/cmd/thanos/sidecar.go
index 61f493f93a8..1662a310fa8 100644
--- a/cmd/thanos/sidecar.go
+++ b/cmd/thanos/sidecar.go
@@ -14,7 +14,7 @@ import (
 
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
-	"github.com/improbable-eng/thanos/pkg/block"
+	"github.com/improbable-eng/thanos/pkg/block/blockmeta"
 	"github.com/improbable-eng/thanos/pkg/cluster"
 	"github.com/improbable-eng/thanos/pkg/objstore/client"
 	"github.com/improbable-eng/thanos/pkg/reloader"
@@ -252,7 +252,7 @@ func runSidecar(
 			}
 		}()
 
-		s := shipper.New(logger, nil, dataDir, bkt, metadata.Labels, block.SidecarSource)
+		s := shipper.New(logger, nil, dataDir, bkt, metadata.Labels, blockmeta.SidecarSource)
 		ctx, cancel := context.WithCancel(context.Background())
 
 		g.Add(func() error {
diff --git a/pkg/block/block.go b/pkg/block/block.go
index 118b7ea96c8..e6750e0881c 100644
--- a/pkg/block/block.go
+++ b/pkg/block/block.go
@@ -5,11 +5,12 @@ package block
 import (
 	"context"
 	"encoding/json"
-	"io/ioutil"
 	"os"
 	"path"
 	"path/filepath"
 
+	"github.com/improbable-eng/thanos/pkg/block/blockmeta"
+
 	"fmt"
 
 	"github.com/go-kit/kit/log"
@@ -17,8 +18,6 @@ import (
 	"github.com/improbable-eng/thanos/pkg/runutil"
 	"github.com/oklog/ulid"
 	"github.com/pkg/errors"
-	"github.com/prometheus/tsdb"
-	"github.com/prometheus/tsdb/fileutil"
 )
 
 const (
@@ -33,103 +32,6 @@ const (
 	DebugMetas = "debug/metas"
 )
 
-type SourceType string
-
-const (
-	UnknownSource         SourceType = ""
-	SidecarSource         SourceType = "sidecar"
-	CompactorSource       SourceType = "compactor"
-	CompactorRepairSource SourceType = "compactor.repair"
-	RulerSource           SourceType = "ruler"
-	BucketRepairSource    SourceType = "bucket.repair"
-	TestSource            SourceType = "test"
-)
-
-// Meta describes the a block's meta. It wraps the known TSDB meta structure and
-// extends it by Thanos-specific fields.
-type Meta struct {
-	Version int `json:"version"`
-
-	tsdb.BlockMeta
-
-	Thanos ThanosMeta `json:"thanos"`
-}
-
-// ThanosMeta holds block meta information specific to Thanos.
-type ThanosMeta struct {
-	Labels     map[string]string    `json:"labels"`
-	Downsample ThanosDownsampleMeta `json:"downsample"`
-
-	// Source is a real upload source of the block.
-	Source SourceType `json:"source"`
-}
-
-type ThanosDownsampleMeta struct {
-	Resolution int64 `json:"resolution"`
-}
-
-// WriteMetaFile writes the given meta into <dir>/meta.json.
-func WriteMetaFile(logger log.Logger, dir string, meta *Meta) error {
-	// Make any changes to the file appear atomic.
-	path := filepath.Join(dir, MetaFilename)
-	tmp := path + ".tmp"
-
-	f, err := os.Create(tmp)
-	if err != nil {
-		return err
-	}
-
-	enc := json.NewEncoder(f)
-	enc.SetIndent("", "\t")
-
-	if err := enc.Encode(meta); err != nil {
-		runutil.CloseWithLogOnErr(logger, f, "close meta")
-		return err
-	}
-	if err := f.Close(); err != nil {
-		return err
-	}
-	return renameFile(logger, tmp, path)
-}
-
-// ReadMetaFile reads the given meta from <dir>/meta.json.
-func ReadMetaFile(dir string) (*Meta, error) {
-	b, err := ioutil.ReadFile(filepath.Join(dir, MetaFilename))
-	if err != nil {
-		return nil, err
-	}
-	var m Meta
-
-	if err := json.Unmarshal(b, &m); err != nil {
-		return nil, err
-	}
-	if m.Version != 1 {
-		return nil, errors.Errorf("unexpected meta file version %d", m.Version)
-	}
-	return &m, nil
-}
-
-func renameFile(logger log.Logger, from, to string) error {
-	if err := os.RemoveAll(to); err != nil {
-		return err
-	}
-	if err := os.Rename(from, to); err != nil {
-		return err
-	}
-
-	// Directory was renamed; sync parent dir to persist rename.
-	pdir, err := fileutil.OpenDir(filepath.Dir(to))
-	if err != nil {
-		return err
-	}
-
-	if err = fileutil.Fsync(pdir); err != nil {
-		runutil.CloseWithLogOnErr(logger, pdir, "close dir")
-		return err
-	}
-	return pdir.Close()
-}
-
 // Download downloads directory that is mean to be block directory.
 func Download(ctx context.Context, logger log.Logger, bucket objstore.Bucket, id ulid.ULID, dst string) error {
 	if err := objstore.DownloadDir(ctx, logger, bucket, id.String(), dst); err != nil {
@@ -169,7 +71,7 @@ func Upload(ctx context.Context, logger log.Logger, bkt objstore.Bucket, bdir st
 		return errors.Wrap(err, "not a block dir")
 	}
 
-	meta, err := ReadMetaFile(bdir)
+	meta, err := blockmeta.Read(bdir)
 	if err != nil {
 		// No meta or broken meta file.
 		return errors.Wrap(err, "read meta")
@@ -216,16 +118,16 @@ func Delete(ctx context.Context, bucket objstore.Bucket, id ulid.ULID) error {
 }
 
 // DownloadMeta downloads only meta file from bucket by block ID.
-func DownloadMeta(ctx context.Context, logger log.Logger, bkt objstore.Bucket, id ulid.ULID) (Meta, error) {
+func DownloadMeta(ctx context.Context, logger log.Logger, bkt objstore.Bucket, id ulid.ULID) (blockmeta.Meta, error) {
 	rc, err := bkt.Get(ctx, path.Join(id.String(), MetaFilename))
 	if err != nil {
-		return Meta{}, errors.Wrapf(err, "meta.json bkt get for %s", id.String())
+		return blockmeta.Meta{}, errors.Wrapf(err, "meta.json bkt get for %s", id.String())
 	}
 	defer runutil.CloseWithLogOnErr(logger, rc, "download meta bucket client")
 
-	var m Meta
+	var m blockmeta.Meta
 	if err := json.NewDecoder(rc).Decode(&m); err != nil {
-		return Meta{}, errors.Wrapf(err, "decode meta.json for block %s", id.String())
+		return blockmeta.Meta{}, errors.Wrapf(err, "decode meta.json for block %s", id.String())
 	}
 	return m, nil
 }
@@ -234,24 +136,3 @@ func IsBlockDir(path string) (id ulid.ULID, ok bool) {
 	id, err := ulid.Parse(filepath.Base(path))
 	return id, err == nil
 }
-
-// InjectThanosMeta sets Thanos meta to the block meta JSON and saves it to the disk.
-// NOTE: It should be used after writing any block by any Thanos component, otherwise we will miss crucial metadata.
-func InjectThanosMeta(logger log.Logger, bdir string, meta ThanosMeta, downsampledMeta *tsdb.BlockMeta) (*Meta, error) {
-	newMeta, err := ReadMetaFile(bdir)
-	if err != nil {
-		return nil, errors.Wrap(err, "read new meta")
-	}
-	newMeta.Thanos = meta
-
-	// While downsampling we need to copy original compaction.
-	if downsampledMeta != nil {
-		newMeta.Compaction = downsampledMeta.Compaction
-	}
-
-	if err := WriteMetaFile(logger, bdir, newMeta); err != nil {
-		return nil, errors.Wrap(err, "write new meta")
-	}
-
-	return newMeta, nil
-}
diff --git a/pkg/block/blockmeta/meta.go b/pkg/block/blockmeta/meta.go
new file mode 100644
index 00000000000..d470b4ec2c7
--- /dev/null
+++ b/pkg/block/blockmeta/meta.go
@@ -0,0 +1,142 @@
+package blockmeta
+
+// blockmeta package is implements writing and reading wrapped meta.json where Thanos puts its metadata.
+// Those metadata contains external labels, downsampling resolution and source type.
+// This package is minimal and separated because it usited by testutils which limits test helpers we can use in
+// this package.
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+
+	"github.com/go-kit/kit/log"
+	"github.com/improbable-eng/thanos/pkg/runutil"
+	"github.com/pkg/errors"
+	"github.com/prometheus/tsdb"
+	"github.com/prometheus/tsdb/fileutil"
+)
+
+type SourceType string
+
+const (
+	UnknownSource         SourceType = ""
+	SidecarSource         SourceType = "sidecar"
+	CompactorSource       SourceType = "compactor"
+	CompactorRepairSource SourceType = "compactor.repair"
+	RulerSource           SourceType = "ruler"
+	BucketRepairSource    SourceType = "bucket.repair"
+	TestSource            SourceType = "test"
+)
+
+const (
+	// MetaFilename is the known JSON filename for meta information.
+	MetaFilename = "meta.json"
+)
+
+// Meta describes the a block's meta. It wraps the known TSDB meta structure and
+// extends it by Thanos-specific fields.
+type Meta struct {
+	Version int `json:"version"`
+
+	tsdb.BlockMeta
+
+	Thanos Thanos `json:"thanos"`
+}
+
+// Thanos holds block meta information specific to Thanos.
+type Thanos struct {
+	Labels     map[string]string `json:"labels"`
+	Downsample ThanosDownsample  `json:"downsample"`
+
+	// Source is a real upload source of the block.
+	Source SourceType `json:"source"`
+}
+
+type ThanosDownsample struct {
+	Resolution int64 `json:"resolution"`
+}
+
+// InjectThanos sets Thanos meta to the block meta JSON and saves it to the disk.
+// NOTE: It should be used after writing any block by any Thanos component, otherwise we will miss crucial metadata.
+func InjectThanos(logger log.Logger, bdir string, meta Thanos, downsampledMeta *tsdb.BlockMeta) (*Meta, error) {
+	newMeta, err := Read(bdir)
+	if err != nil {
+		return nil, errors.Wrap(err, "read new meta")
+	}
+	newMeta.Thanos = meta
+
+	// While downsampling we need to copy original compaction.
+	if downsampledMeta != nil {
+		newMeta.Compaction = downsampledMeta.Compaction
+	}
+
+	if err := Write(logger, bdir, newMeta); err != nil {
+		return nil, errors.Wrap(err, "write new meta")
+	}
+
+	return newMeta, nil
+}
+
+// Write writes the given meta into <dir>/meta.json.
+func Write(logger log.Logger, dir string, meta *Meta) error {
+	// Make any changes to the file appear atomic.
+	path := filepath.Join(dir, MetaFilename)
+	tmp := path + ".tmp"
+
+	f, err := os.Create(tmp)
+	if err != nil {
+		return err
+	}
+
+	enc := json.NewEncoder(f)
+	enc.SetIndent("", "\t")
+
+	if err := enc.Encode(meta); err != nil {
+		runutil.CloseWithLogOnErr(logger, f, "close meta")
+		return err
+	}
+	if err := f.Close(); err != nil {
+		return err
+	}
+	return renameFile(logger, tmp, path)
+}
+
+func renameFile(logger log.Logger, from, to string) error {
+	if err := os.RemoveAll(to); err != nil {
+		return err
+	}
+	if err := os.Rename(from, to); err != nil {
+		return err
+	}
+
+	// Directory was renamed; sync parent dir to persist rename.
+	pdir, err := fileutil.OpenDir(filepath.Dir(to))
+	if err != nil {
+		return err
+	}
+
+	if err = fileutil.Fsync(pdir); err != nil {
+		runutil.CloseWithLogOnErr(logger, pdir, "close dir")
+		return err
+	}
+	return pdir.Close()
+}
+
+// Read reads the given meta from <dir>/meta.json.
+func Read(dir string) (*Meta, error) {
+	b, err := ioutil.ReadFile(filepath.Join(dir, MetaFilename))
+	if err != nil {
+		return nil, err
+	}
+	var m Meta
+
+	if err := json.Unmarshal(b, &m); err != nil {
+		return nil, err
+	}
+	if m.Version != 1 {
+		return nil, errors.Errorf("unexpected meta file version %d", m.Version)
+	}
+	return &m, nil
+}
diff --git a/pkg/block/index.go b/pkg/block/index.go
index 2249863b2d2..2d088953fc8 100644
--- a/pkg/block/index.go
+++ b/pkg/block/index.go
@@ -11,6 +11,10 @@ import (
 	"strings"
 	"time"
 
+	"github.com/improbable-eng/thanos/pkg/block/blockmeta"
+
+	"github.com/prometheus/tsdb/fileutil"
+
 	"github.com/go-kit/kit/log"
 	"github.com/improbable-eng/thanos/pkg/runutil"
 	"github.com/oklog/ulid"
@@ -36,23 +40,84 @@ type indexCache struct {
 	Postings    []postingsRange
 }
 
+type realByteSlice []byte
+
+func (b realByteSlice) Len() int {
+	return len(b)
+}
+
+func (b realByteSlice) Range(start, end int) []byte {
+	return b[start:end]
+}
+
+func (b realByteSlice) Sub(start, end int) index.ByteSlice {
+	return b[start:end]
+}
+
+func getSymbolTable(b index.ByteSlice) (map[uint32]string, error) {
+	version := int(b.Range(4, 5)[0])
+
+	if version != 1 && version != 2 {
+		return nil, errors.Errorf("unknown index file version %d", version)
+	}
+
+	toc, err := index.NewTOCFromByteSlice(b)
+	if err != nil {
+		return nil, errors.Wrap(err, "read TOC")
+	}
+
+	symbolsV2, symbolsV1, err := index.ReadSymbols(b, version, int(toc.Symbols))
+	if err != nil {
+		return nil, errors.Wrap(err, "read symbols")
+	}
+
+	symbolsTable := make(map[uint32]string, len(symbolsV1)+len(symbolsV2))
+	for o, s := range symbolsV1 {
+		symbolsTable[o] = s
+	}
+	for o, s := range symbolsV2 {
+		symbolsTable[uint32(o)] = s
+	}
+
+	return symbolsTable, nil
+}
+
 // WriteIndexCache writes a cache file containing the first lookup stages
 // for an index file.
-func WriteIndexCache(logger log.Logger, fn string, r *index.Reader) error {
+func WriteIndexCache(logger log.Logger, indexFn string, fn string) error {
+	indexFile, err := fileutil.OpenMmapFile(indexFn)
+	if err != nil {
+		return errors.Wrapf(err, "open mmap index file %s", indexFn)
+	}
+	defer runutil.CloseWithLogOnErr(logger, indexFile, "close index cache mmap file from %s", indexFn)
+
+	b := realByteSlice(indexFile.Bytes())
+	indexr, err := index.NewReader(b)
+	if err != nil {
+		return errors.Wrap(err, "open index reader")
+	}
+	defer runutil.CloseWithLogOnErr(logger, indexr, "load index cache reader")
+
+	// We assume reader verified index already.
+	symbols, err := getSymbolTable(b)
+	if err != nil {
+		return err
+	}
+
 	f, err := os.Create(fn)
 	if err != nil {
-		return errors.Wrap(err, "create file")
+		return errors.Wrap(err, "create index cache file")
 	}
 	defer runutil.CloseWithLogOnErr(logger, f, "index cache writer")
 
 	v := indexCache{
-		Version:     r.Version(),
-		Symbols:     r.SymbolTable(),
+		Version:     indexr.Version(),
+		Symbols:     symbols,
 		LabelValues: map[string][]string{},
 	}
 
 	// Extract label value indices.
-	lnames, err := r.LabelIndices()
+	lnames, err := indexr.LabelIndices()
 	if err != nil {
 		return errors.Wrap(err, "read label indices")
 	}
@@ -62,7 +127,7 @@ func WriteIndexCache(logger log.Logger, fn string, r *index.Reader) error {
 		}
 		ln := lns[0]
 
-		tpls, err := r.LabelValues(ln)
+		tpls, err := indexr.LabelValues(ln)
 		if err != nil {
 			return errors.Wrap(err, "get label values")
 		}
@@ -82,7 +147,7 @@ func WriteIndexCache(logger log.Logger, fn string, r *index.Reader) error {
 	}
 
 	// Extract postings ranges.
-	pranges, err := r.PostingsRanges()
+	pranges, err := indexr.PostingsRanges()
 	if err != nil {
 		return errors.Wrap(err, "read postings ranges")
 	}
@@ -164,7 +229,7 @@ func VerifyIndex(logger log.Logger, fn string, minTime int64, maxTime int64) err
 }
 
 type Stats struct {
-	// TotalSeries represents total number of series in block.
+	// TotalSeries represnts total number of series in block.
 	TotalSeries int
 	// OutOfOrderSeries represents number of series that have out of order chunks.
 	OutOfOrderSeries int
@@ -346,7 +411,7 @@ type ignoreFnType func(mint, maxt int64, prev *chunks.Meta, curr *chunks.Meta) (
 // - removes all near "complete" outside chunks introduced by https://github.com/prometheus/tsdb/issues/347.
 // Fixable inconsistencies are resolved in the new block.
 // TODO(bplotka): https://github.com/improbable-eng/thanos/issues/378
-func Repair(logger log.Logger, dir string, id ulid.ULID, source SourceType, ignoreChkFns ...ignoreFnType) (resid ulid.ULID, err error) {
+func Repair(logger log.Logger, dir string, id ulid.ULID, source blockmeta.SourceType, ignoreChkFns ...ignoreFnType) (resid ulid.ULID, err error) {
 	if len(ignoreChkFns) == 0 {
 		return resid, errors.New("no ignore chunk function specified")
 	}
@@ -355,7 +420,7 @@ func Repair(logger log.Logger, dir string, id ulid.ULID, source SourceType, igno
 	entropy := rand.New(rand.NewSource(time.Now().UnixNano()))
 	resid = ulid.MustNew(ulid.Now(), entropy)
 
-	meta, err := ReadMetaFile(bdir)
+	meta, err := blockmeta.Read(bdir)
 	if err != nil {
 		return resid, errors.Wrap(err, "read meta file")
 	}
@@ -405,7 +470,7 @@ func Repair(logger log.Logger, dir string, id ulid.ULID, source SourceType, igno
 	if err := rewrite(indexr, chunkr, indexw, chunkw, &resmeta, ignoreChkFns); err != nil {
 		return resid, errors.Wrap(err, "rewrite block")
 	}
-	if err := WriteMetaFile(logger, resdir, &resmeta); err != nil {
+	if err := blockmeta.Write(logger, resdir, &resmeta); err != nil {
 		return resid, err
 	}
 	return resid, nil
@@ -494,7 +559,7 @@ OUTER:
 func rewrite(
 	indexr tsdb.IndexReader, chunkr tsdb.ChunkReader,
 	indexw tsdb.IndexWriter, chunkw tsdb.ChunkWriter,
-	meta *Meta,
+	meta *blockmeta.Meta,
 	ignoreChkFns []ignoreFnType,
 ) error {
 	symbols, err := indexr.Symbols()
diff --git a/pkg/block/index_test.go b/pkg/block/index_test.go
new file mode 100644
index 00000000000..80c10e8e6ed
--- /dev/null
+++ b/pkg/block/index_test.go
@@ -0,0 +1,46 @@
+package block
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/go-kit/kit/log"
+	"github.com/improbable-eng/thanos/pkg/testutil"
+	"github.com/prometheus/tsdb/labels"
+)
+
+func TestWriteReadIndexCache(t *testing.T) {
+	tmpDir, err := ioutil.TempDir("", "test-compact-prepare")
+	testutil.Ok(t, err)
+	defer func() { testutil.Ok(t, os.RemoveAll(tmpDir)) }()
+
+	b, err := testutil.CreateBlock(tmpDir, []labels.Labels{
+		{{Name: "a", Value: "1"}},
+		{{Name: "a", Value: "2"}},
+		{{Name: "a", Value: "3"}},
+		{{Name: "a", Value: "4"}},
+		{{Name: "b", Value: "1"}},
+	}, 100, 0, 1000, nil, 124)
+	testutil.Ok(t, err)
+
+	fn := filepath.Join(tmpDir, "index.cache.json")
+	testutil.Ok(t, WriteIndexCache(log.NewNopLogger(), filepath.Join(tmpDir, b.String(), "index"), fn))
+
+	version, symbols, lvals, postings, err := ReadIndexCache(log.NewNopLogger(), fn)
+	testutil.Ok(t, err)
+
+	testutil.Equals(t, 2, version)
+	testutil.Equals(t, 6, len(symbols))
+	testutil.Equals(t, 2, len(lvals))
+
+	vals, ok := lvals["a"]
+	testutil.Assert(t, ok, "")
+	testutil.Equals(t, []string{"1", "2", "3", "4"}, vals)
+
+	vals, ok = lvals["b"]
+	testutil.Assert(t, ok, "")
+	testutil.Equals(t, []string{"1"}, vals)
+	testutil.Equals(t, 6, len(postings))
+}
diff --git a/pkg/compact/compact.go b/pkg/compact/compact.go
index 544de920eac..fe95ccfd719 100644
--- a/pkg/compact/compact.go
+++ b/pkg/compact/compact.go
@@ -9,6 +9,8 @@ import (
 	"sync"
 	"time"
 
+	"github.com/improbable-eng/thanos/pkg/block/blockmeta"
+
 	"io/ioutil"
 
 	"github.com/go-kit/kit/log"
@@ -39,7 +41,7 @@ type Syncer struct {
 	bkt       objstore.Bucket
 	syncDelay time.Duration
 	mtx       sync.Mutex
-	blocks    map[ulid.ULID]*block.Meta
+	blocks    map[ulid.ULID]*blockmeta.Meta
 	metrics   *syncerMetrics
 }
 
@@ -130,7 +132,7 @@ func NewSyncer(logger log.Logger, reg prometheus.Registerer, bkt objstore.Bucket
 		logger:    logger,
 		reg:       reg,
 		syncDelay: syncDelay,
-		blocks:    map[ulid.ULID]*block.Meta{},
+		blocks:    map[ulid.ULID]*blockmeta.Meta{},
 		bkt:       bkt,
 		metrics:   newSyncerMetrics(reg),
 	}, nil
@@ -185,9 +187,9 @@ func (c *Syncer) syncMetas(ctx context.Context) error {
 		// NOTE: It is not safe to miss "old" block (even that it is newly created) in sync step. Compactor needs to aware of ALL old blocks.
 		// TODO(bplotka): https://github.com/improbable-eng/thanos/issues/377
 		if ulid.Now()-id.Time() < uint64(c.syncDelay/time.Millisecond) &&
-			meta.Thanos.Source != block.BucketRepairSource &&
-			meta.Thanos.Source != block.CompactorSource &&
-			meta.Thanos.Source != block.CompactorRepairSource {
+			meta.Thanos.Source != blockmeta.BucketRepairSource &&
+			meta.Thanos.Source != blockmeta.CompactorSource &&
+			meta.Thanos.Source != blockmeta.CompactorRepairSource {
 
 			level.Debug(c.logger).Log("msg", "block is too fresh for now", "block", id)
 			return nil
@@ -214,7 +216,7 @@ func (c *Syncer) syncMetas(ctx context.Context) error {
 
 // GroupKey returns a unique identifier for the group the block belongs to. It considers
 // the downsampling resolution and the block's labels.
-func GroupKey(meta block.Meta) string {
+func GroupKey(meta blockmeta.Meta) string {
 	return groupKey(meta.Thanos.Downsample.Resolution, labels.FromMap(meta.Thanos.Labels))
 }
 
@@ -381,7 +383,7 @@ type Group struct {
 	labels                      labels.Labels
 	resolution                  int64
 	mtx                         sync.Mutex
-	blocks                      map[ulid.ULID]*block.Meta
+	blocks                      map[ulid.ULID]*blockmeta.Meta
 	compactions                 prometheus.Counter
 	compactionFailures          prometheus.Counter
 	groupGarbageCollectedBlocks prometheus.Counter
@@ -405,7 +407,7 @@ func newGroup(
 		bkt:                         bkt,
 		labels:                      lset,
 		resolution:                  resolution,
-		blocks:                      map[ulid.ULID]*block.Meta{},
+		blocks:                      map[ulid.ULID]*blockmeta.Meta{},
 		compactions:                 compactions,
 		compactionFailures:          compactionFailures,
 		groupGarbageCollectedBlocks: groupGarbageCollectedBlocks,
@@ -419,7 +421,7 @@ func (cg *Group) Key() string {
 }
 
 // Add the block with the given meta to the group.
-func (cg *Group) Add(meta *block.Meta) error {
+func (cg *Group) Add(meta *blockmeta.Meta) error {
 	cg.mtx.Lock()
 	defer cg.mtx.Unlock()
 
@@ -541,7 +543,7 @@ func IsRetryError(err error) bool {
 	return ok
 }
 
-func (cg *Group) areBlocksOverlapping(include *block.Meta, excludeDirs ...string) error {
+func (cg *Group) areBlocksOverlapping(include *blockmeta.Meta, excludeDirs ...string) error {
 	var (
 		metas   []tsdb.BlockMeta
 		exclude = map[ulid.ULID]struct{}{}
@@ -597,12 +599,12 @@ func RepairIssue347(ctx context.Context, logger log.Logger, bkt objstore.Bucket,
 		return retry(errors.Wrapf(err, "download block %s", ie.id))
 	}
 
-	meta, err := block.ReadMetaFile(bdir)
+	meta, err := blockmeta.Read(bdir)
 	if err != nil {
 		return errors.Wrapf(err, "read meta from %s", bdir)
 	}
 
-	resid, err := block.Repair(logger, tmpdir, ie.id, block.CompactorRepairSource, block.IgnoreIssue347OutsideChunk)
+	resid, err := block.Repair(logger, tmpdir, ie.id, blockmeta.CompactorRepairSource, block.IgnoreIssue347OutsideChunk)
 	if err != nil {
 		return errors.Wrapf(err, "repair failed for block %s", ie.id)
 	}
@@ -647,7 +649,7 @@ func (cg *Group) compact(ctx context.Context, dir string, comp tsdb.Compactor) (
 		if err := os.MkdirAll(bdir, 0777); err != nil {
 			return compID, errors.Wrap(err, "create planning block dir")
 		}
-		if err := block.WriteMetaFile(cg.logger, bdir, meta); err != nil {
+		if err := blockmeta.Write(cg.logger, bdir, meta); err != nil {
 			return compID, errors.Wrap(err, "write planning meta file")
 		}
 	}
@@ -670,7 +672,7 @@ func (cg *Group) compact(ctx context.Context, dir string, comp tsdb.Compactor) (
 	begin := time.Now()
 
 	for _, pdir := range plan {
-		meta, err := block.ReadMetaFile(pdir)
+		meta, err := blockmeta.Read(pdir)
 		if err != nil {
 			return compID, errors.Wrapf(err, "read meta from %s", pdir)
 		}
@@ -718,7 +720,7 @@ func (cg *Group) compact(ctx context.Context, dir string, comp tsdb.Compactor) (
 
 	begin = time.Now()
 
-	compID, err = comp.Compact(dir, plan...)
+	compID, err = comp.Compact(dir, plan, nil)
 	if err != nil {
 		return compID, halt(errors.Wrapf(err, "compact blocks %v", plan))
 	}
@@ -727,10 +729,10 @@ func (cg *Group) compact(ctx context.Context, dir string, comp tsdb.Compactor) (
 
 	bdir := filepath.Join(dir, compID.String())
 
-	newMeta, err := block.InjectThanosMeta(cg.logger, bdir, block.ThanosMeta{
+	newMeta, err := blockmeta.InjectThanos(cg.logger, bdir, blockmeta.Thanos{
 		Labels:     cg.labels.Map(),
-		Downsample: block.ThanosDownsampleMeta{Resolution: cg.resolution},
-		Source:     block.CompactorSource,
+		Downsample: blockmeta.ThanosDownsample{Resolution: cg.resolution},
+		Source:     blockmeta.CompactorSource,
 	}, nil)
 	if err != nil {
 		return compID, errors.Wrapf(err, "failed to finalize the block %s", bdir)
diff --git a/pkg/compact/compact_e2e_test.go b/pkg/compact/compact_e2e_test.go
index 74df73cc6f5..266fb93cdf3 100644
--- a/pkg/compact/compact_e2e_test.go
+++ b/pkg/compact/compact_e2e_test.go
@@ -13,6 +13,8 @@ import (
 	"testing"
 	"time"
 
+	"github.com/improbable-eng/thanos/pkg/block/blockmeta"
+
 	"github.com/go-kit/kit/log"
 	"github.com/improbable-eng/thanos/pkg/block"
 	"github.com/improbable-eng/thanos/pkg/objstore"
@@ -37,13 +39,13 @@ func TestSyncer_SyncMetas_e2e(t *testing.T) {
 		// After the first synchronization the first 5 should be dropped and the
 		// last 5 be loaded from the bucket.
 		var ids []ulid.ULID
-		var metas []*block.Meta
+		var metas []*blockmeta.Meta
 
 		for i := 0; i < 15; i++ {
 			id, err := ulid.New(uint64(i), nil)
 			testutil.Ok(t, err)
 
-			var meta block.Meta
+			var meta blockmeta.Meta
 			meta.Version = 1
 			meta.ULID = id
 
@@ -56,7 +58,7 @@ func TestSyncer_SyncMetas_e2e(t *testing.T) {
 		for _, m := range metas[5:] {
 			var buf bytes.Buffer
 			testutil.Ok(t, json.NewEncoder(&buf).Encode(&m))
-			testutil.Ok(t, bkt.Upload(ctx, path.Join(m.ULID.String(), block.MetaFilename), &buf))
+			testutil.Ok(t, bkt.Upload(ctx, path.Join(m.ULID.String(), blockmeta.MetaFilename), &buf))
 		}
 
 		groups, err := sy.Groups()
@@ -79,11 +81,11 @@ func TestSyncer_GarbageCollect_e2e(t *testing.T) {
 
 		// Generate 10 source block metas and construct higher level blocks
 		// that are higher compactions of them.
-		var metas []*block.Meta
+		var metas []*blockmeta.Meta
 		var ids []ulid.ULID
 
 		for i := 0; i < 10; i++ {
-			var m block.Meta
+			var m blockmeta.Meta
 
 			m.Version = 1
 			m.ULID = ulid.MustNew(uint64(i), nil)
@@ -94,28 +96,28 @@ func TestSyncer_GarbageCollect_e2e(t *testing.T) {
 			metas = append(metas, &m)
 		}
 
-		var m1 block.Meta
+		var m1 blockmeta.Meta
 		m1.Version = 1
 		m1.ULID = ulid.MustNew(100, nil)
 		m1.Compaction.Level = 2
 		m1.Compaction.Sources = ids[:4]
 		m1.Thanos.Downsample.Resolution = 0
 
-		var m2 block.Meta
+		var m2 blockmeta.Meta
 		m2.Version = 1
 		m2.ULID = ulid.MustNew(200, nil)
 		m2.Compaction.Level = 2
 		m2.Compaction.Sources = ids[4:8] // last two source IDs is not part of a level 2 block.
 		m2.Thanos.Downsample.Resolution = 0
 
-		var m3 block.Meta
+		var m3 blockmeta.Meta
 		m3.Version = 1
 		m3.ULID = ulid.MustNew(300, nil)
 		m3.Compaction.Level = 3
 		m3.Compaction.Sources = ids[:9] // last source ID is not part of level 3 block.
 		m3.Thanos.Downsample.Resolution = 0
 
-		var m4 block.Meta
+		var m4 blockmeta.Meta
 		m4.Version = 14
 		m4.ULID = ulid.MustNew(400, nil)
 		m4.Compaction.Level = 2
@@ -127,7 +129,7 @@ func TestSyncer_GarbageCollect_e2e(t *testing.T) {
 			fmt.Println("create", m.ULID)
 			var buf bytes.Buffer
 			testutil.Ok(t, json.NewEncoder(&buf).Encode(&m))
-			testutil.Ok(t, bkt.Upload(ctx, path.Join(m.ULID.String(), block.MetaFilename), &buf))
+			testutil.Ok(t, bkt.Upload(ctx, path.Join(m.ULID.String(), blockmeta.MetaFilename), &buf))
 		}
 
 		// Do one initial synchronization with the bucket.
@@ -173,7 +175,7 @@ func TestGroup_Compact_e2e(t *testing.T) {
 		ctx, cancel := context.WithTimeout(context.Background(), 120*time.Second)
 		defer cancel()
 
-		var metas []*block.Meta
+		var metas []*blockmeta.Meta
 		extLset := labels.Labels{{Name: "e1", Value: "1"}}
 		b1, err := testutil.CreateBlock(prepareDir, []labels.Labels{
 			{{Name: "a", Value: "1"}},
@@ -183,7 +185,7 @@ func TestGroup_Compact_e2e(t *testing.T) {
 		}, 100, 0, 1000, extLset, 124)
 		testutil.Ok(t, err)
 
-		meta, err := block.ReadMetaFile(filepath.Join(prepareDir, b1.String()))
+		meta, err := blockmeta.Read(filepath.Join(prepareDir, b1.String()))
 		testutil.Ok(t, err)
 		metas = append(metas, meta)
 
@@ -196,7 +198,7 @@ func TestGroup_Compact_e2e(t *testing.T) {
 		testutil.Ok(t, err)
 
 		// Mix order to make sure compact is able to deduct min time / max time.
-		meta, err = block.ReadMetaFile(filepath.Join(prepareDir, b3.String()))
+		meta, err = blockmeta.Read(filepath.Join(prepareDir, b3.String()))
 		testutil.Ok(t, err)
 		metas = append(metas, meta)
 
@@ -204,7 +206,7 @@ func TestGroup_Compact_e2e(t *testing.T) {
 		b2, err := testutil.CreateBlock(prepareDir, []labels.Labels{}, 100, 1001, 2000, extLset, 124)
 		testutil.Ok(t, err)
 
-		meta, err = block.ReadMetaFile(filepath.Join(prepareDir, b2.String()))
+		meta, err = blockmeta.Read(filepath.Join(prepareDir, b2.String()))
 		testutil.Ok(t, err)
 		metas = append(metas, meta)
 
@@ -217,7 +219,7 @@ func TestGroup_Compact_e2e(t *testing.T) {
 		}, 100, 3001, 4000, extLset, 124)
 		testutil.Ok(t, err)
 
-		meta, err = block.ReadMetaFile(filepath.Join(prepareDir, freshB.String()))
+		meta, err = blockmeta.Read(filepath.Join(prepareDir, freshB.String()))
 		testutil.Ok(t, err)
 		metas = append(metas, meta)
 
@@ -263,7 +265,7 @@ func TestGroup_Compact_e2e(t *testing.T) {
 		resDir := filepath.Join(dir, id.String())
 		testutil.Ok(t, block.Download(ctx, log.NewNopLogger(), bkt, id, resDir))
 
-		meta, err = block.ReadMetaFile(resDir)
+		meta, err = blockmeta.Read(resDir)
 		testutil.Ok(t, err)
 
 		testutil.Equals(t, int64(0), meta.MinTime)
diff --git a/pkg/compact/downsample/downsample.go b/pkg/compact/downsample/downsample.go
index 305f72021c0..5b69b3dc7ff 100644
--- a/pkg/compact/downsample/downsample.go
+++ b/pkg/compact/downsample/downsample.go
@@ -5,7 +5,8 @@ import (
 	"path/filepath"
 	"sort"
 
-	"github.com/improbable-eng/thanos/pkg/block"
+	"github.com/improbable-eng/thanos/pkg/block/blockmeta"
+
 	"github.com/prometheus/prometheus/pkg/value"
 	"github.com/prometheus/tsdb/chunkenc"
 
@@ -31,7 +32,7 @@ const (
 // Downsample downsamples the given block. It writes a new block into dir and returns its ID.
 func Downsample(
 	logger log.Logger,
-	origMeta *block.Meta,
+	origMeta *blockmeta.Meta,
 	b tsdb.BlockReader,
 	dir string,
 	resolution int64,
@@ -125,18 +126,18 @@ func Downsample(
 	if err != nil {
 		return id, errors.Wrap(err, "create compactor")
 	}
-	id, err = comp.Write(dir, newb, origMeta.MinTime, origMeta.MaxTime)
+	id, err = comp.Write(dir, newb, origMeta.MinTime, origMeta.MaxTime, &origMeta.BlockMeta)
 	if err != nil {
 		return id, errors.Wrap(err, "compact head")
 	}
 	bdir := filepath.Join(dir, id.String())
 
-	var tmeta block.ThanosMeta
+	var tmeta blockmeta.Thanos
 	tmeta = origMeta.Thanos
-	tmeta.Source = block.CompactorSource
+	tmeta.Source = blockmeta.CompactorSource
 	tmeta.Downsample.Resolution = resolution
 
-	_, err = block.InjectThanosMeta(logger, bdir, tmeta, &origMeta.BlockMeta)
+	_, err = blockmeta.InjectThanos(logger, bdir, tmeta, &origMeta.BlockMeta)
 	if err != nil {
 		return id, errors.Wrapf(err, "failed to finalize the block %s", bdir)
 	}
@@ -228,13 +229,20 @@ func (b *memBlock) Chunks() (tsdb.ChunkReader, error) {
 }
 
 func (b *memBlock) Tombstones() (tsdb.TombstoneReader, error) {
-	return tsdb.EmptyTombstoneReader(), nil
+	return emptyTombstoneReader{}, nil
 }
 
 func (b *memBlock) Close() error {
 	return nil
 }
 
+type emptyTombstoneReader struct{}
+
+func (emptyTombstoneReader) Get(ref uint64) (tsdb.Intervals, error)        { return nil, nil }
+func (emptyTombstoneReader) Iter(func(uint64, tsdb.Intervals) error) error { return nil }
+func (emptyTombstoneReader) Total() uint64                                 { return 0 }
+func (emptyTombstoneReader) Close() error                                  { return nil }
+
 // currentWindow returns the end timestamp of the window that t falls into.
 func currentWindow(t, r int64) int64 {
 	// The next timestamp is the next number after s.t that's aligned with window.
diff --git a/pkg/compact/downsample/downsample_test.go b/pkg/compact/downsample/downsample_test.go
index d3844784162..1d82dabe77a 100644
--- a/pkg/compact/downsample/downsample_test.go
+++ b/pkg/compact/downsample/downsample_test.go
@@ -7,6 +7,8 @@ import (
 	"path/filepath"
 	"testing"
 
+	"github.com/improbable-eng/thanos/pkg/block/blockmeta"
+
 	"github.com/prometheus/prometheus/pkg/value"
 
 	"github.com/prometheus/tsdb/chunks"
@@ -59,7 +61,7 @@ func TestDownsampleRaw(t *testing.T) {
 			},
 		},
 	}
-	testDownsample(t, input, &block.Meta{}, 100)
+	testDownsample(t, input, &blockmeta.Meta{}, 100)
 }
 
 func TestDownsampleAggr(t *testing.T) {
@@ -96,7 +98,7 @@ func TestDownsampleAggr(t *testing.T) {
 			},
 		},
 	}
-	var meta block.Meta
+	var meta blockmeta.Meta
 	meta.Thanos.Downsample.Resolution = 10
 
 	testDownsample(t, input, &meta, 500)
@@ -123,7 +125,7 @@ type downsampleTestSet struct {
 
 // testDownsample inserts the input into a block and invokes the downsampler with the given resolution.
 // The chunk ranges within the input block are aligned at 500 time units.
-func testDownsample(t *testing.T, data []*downsampleTestSet, meta *block.Meta, resolution int64) {
+func testDownsample(t *testing.T, data []*downsampleTestSet, meta *blockmeta.Meta, resolution int64) {
 	t.Helper()
 
 	dir, err := ioutil.TempDir("", "downsample-raw")
diff --git a/pkg/query/api/v1.go b/pkg/query/api/v1.go
index 23e5b0a801b..cf693dd2fbe 100644
--- a/pkg/query/api/v1.go
+++ b/pkg/query/api/v1.go
@@ -527,15 +527,16 @@ func (api *API) series(r *http.Request) (interface{}, []error, *apiError) {
 
 	var sets []storage.SeriesSet
 	for _, mset := range matcherSets {
-		s, err := q.Select(&storage.SelectParams{}, mset...)
+		s, _, err := q.Select(&storage.SelectParams{}, mset...)
 		if err != nil {
 			return nil, nil, &apiError{errorExec, err}
 		}
 		sets = append(sets, s)
 	}
 
-	set := storage.NewMergeSeriesSet(sets)
-	metrics := []labels.Labels{}
+	set := storage.NewMergeSeriesSet(sets, nil)
+
+	var metrics []labels.Labels
 	for set.Next() {
 		metrics = append(metrics, set.At().Labels())
 	}
diff --git a/pkg/query/querier.go b/pkg/query/querier.go
index 6e962f64727..819ff3ac2a1 100644
--- a/pkg/query/querier.go
+++ b/pkg/query/querier.go
@@ -169,13 +169,13 @@ func aggrsFromFunc(f string) ([]storepb.Aggr, resAggr) {
 	return []storepb.Aggr{storepb.Aggr_COUNT, storepb.Aggr_SUM}, resAggrAvg
 }
 
-func (q *querier) Select(params *storage.SelectParams, ms ...*labels.Matcher) (storage.SeriesSet, error) {
+func (q *querier) Select(params *storage.SelectParams, ms ...*labels.Matcher) (storage.SeriesSet, storage.Warnings, error) {
 	span, ctx := tracing.StartSpan(q.ctx, "querier_select")
 	defer span.Finish()
 
 	sms, err := translateMatchers(ms...)
 	if err != nil {
-		return nil, errors.Wrap(err, "convert matchers")
+		return nil, nil, errors.Wrap(err, "convert matchers")
 	}
 
 	queryAggrs, resAggr := aggrsFromFunc(params.Func)
@@ -189,10 +189,12 @@ func (q *querier) Select(params *storage.SelectParams, ms ...*labels.Matcher) (s
 		Aggregates:              queryAggrs,
 		PartialResponseDisabled: !q.partialResponse,
 	}, resp); err != nil {
-		return nil, errors.Wrap(err, "proxy Series()")
+		return nil, nil, errors.Wrap(err, "proxy Series()")
 	}
 
 	for _, w := range resp.warnings {
+		// NOTE(bwplotka): We could use warnings return arguments here, however need reporter anyway for LabelValues and LabelNames method,
+		// so we choose to be consistent and keep reporter.
 		q.warningReporter(errors.New(w))
 	}
 
@@ -203,7 +205,7 @@ func (q *querier) Select(params *storage.SelectParams, ms ...*labels.Matcher) (s
 			maxt: q.maxt,
 			set:  newStoreSeriesSet(resp.seriesSet),
 			aggr: resAggr,
-		}, nil
+		}, nil, nil
 	}
 
 	// TODO(fabxc): this could potentially pushed further down into the store API
@@ -220,7 +222,7 @@ func (q *querier) Select(params *storage.SelectParams, ms ...*labels.Matcher) (s
 	// The merged series set assembles all potentially-overlapping time ranges
 	// of the same series into a single one. The series are ordered so that equal series
 	// from different replicas are sequential. We can now deduplicate those.
-	return newDedupSeriesSet(set, q.replicaLabel), nil
+	return newDedupSeriesSet(set, q.replicaLabel), nil, nil
 }
 
 // sortDedupLabels resorts the set so that the same series with different replica
@@ -245,6 +247,7 @@ func sortDedupLabels(set []storepb.Series, replicaLabel string) {
 	})
 }
 
+// LabelValues returns all potential values for a label name.
 func (q *querier) LabelValues(name string) ([]string, error) {
 	span, ctx := tracing.StartSpan(q.ctx, "querier_label_values")
 	defer span.Finish()
@@ -261,6 +264,12 @@ func (q *querier) LabelValues(name string) ([]string, error) {
 	return resp.Values, nil
 }
 
+// LabelNames returns all the unique label names present in the block in sorted order.
+// TODO(bwplotka): Consider adding labelNames to thanos Query API https://github.com/improbable-eng/thanos/issues/702.
+func (q *querier) LabelNames() ([]string, error) {
+	return nil, errors.New("not implemented")
+}
+
 func (q *querier) Close() error {
 	q.cancel()
 	return nil
diff --git a/pkg/query/test_print.go b/pkg/query/test_print.go
new file mode 100644
index 00000000000..70bc292439b
--- /dev/null
+++ b/pkg/query/test_print.go
@@ -0,0 +1,34 @@
+package query
+
+import (
+	"fmt"
+
+	"github.com/prometheus/prometheus/storage"
+)
+
+type printSeriesSet struct {
+	set storage.SeriesSet
+}
+
+func newPrintSeriesSet(set storage.SeriesSet) storage.SeriesSet {
+	return &printSeriesSet{set: set}
+}
+
+func (s *printSeriesSet) Next() bool {
+	return s.set.Next()
+}
+
+func (s *printSeriesSet) At() storage.Series {
+	at := s.set.At()
+	fmt.Println("Series", at.Labels())
+
+	i := at.Iterator()
+	for i.Next() {
+		fmt.Println(i.At())
+	}
+	return at
+}
+
+func (s *printSeriesSet) Err() error {
+	return s.set.Err()
+}
diff --git a/pkg/shipper/shipper.go b/pkg/shipper/shipper.go
index 5c1df9a9b7e..542799ce5e7 100644
--- a/pkg/shipper/shipper.go
+++ b/pkg/shipper/shipper.go
@@ -11,6 +11,8 @@ import (
 	"path"
 	"path/filepath"
 
+	"github.com/improbable-eng/thanos/pkg/block/blockmeta"
+
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
 	"github.com/improbable-eng/thanos/pkg/block"
@@ -69,7 +71,7 @@ type Shipper struct {
 	metrics *metrics
 	bucket  objstore.Bucket
 	labels  func() labels.Labels
-	source  block.SourceType
+	source  blockmeta.SourceType
 }
 
 // New creates a new shipper that detects new TSDB blocks in dir and uploads them
@@ -80,7 +82,7 @@ func New(
 	dir string,
 	bucket objstore.Bucket,
 	lbls func() labels.Labels,
-	source block.SourceType,
+	source blockmeta.SourceType,
 ) *Shipper {
 	if logger == nil {
 		logger = log.NewNopLogger()
@@ -114,7 +116,7 @@ func (s *Shipper) Timestamps() (minTime, maxSyncTime int64, err error) {
 	minTime = math.MaxInt64
 	maxSyncTime = math.MinInt64
 
-	if err := s.iterBlockMetas(func(m *block.Meta) error {
+	if err := s.iterBlockMetas(func(m *blockmeta.Meta) error {
 		if m.MinTime < minTime {
 			minTime = m.MinTime
 		}
@@ -158,7 +160,7 @@ func (s *Shipper) Sync(ctx context.Context) {
 
 	// TODO(bplotka): If there are no blocks in the system check for WAL dir to ensure we have actually
 	// access to real TSDB dir (!).
-	if err = s.iterBlockMetas(func(m *block.Meta) error {
+	if err = s.iterBlockMetas(func(m *blockmeta.Meta) error {
 		// Do not sync a block if we already uploaded it. If it is no longer found in the bucket,
 		// it was generally removed by the compaction process.
 		if _, ok := hasUploaded[m.ULID]; !ok {
@@ -180,7 +182,7 @@ func (s *Shipper) Sync(ctx context.Context) {
 	}
 }
 
-func (s *Shipper) sync(ctx context.Context, meta *block.Meta) (err error) {
+func (s *Shipper) sync(ctx context.Context, meta *blockmeta.Meta) (err error) {
 	dir := filepath.Join(s.dir, meta.ULID.String())
 
 	// We only ship of the first compacted block level.
@@ -225,7 +227,7 @@ func (s *Shipper) sync(ctx context.Context, meta *block.Meta) (err error) {
 		meta.Thanos.Labels = lset.Map()
 	}
 	meta.Thanos.Source = s.source
-	if err := block.WriteMetaFile(s.logger, updir, meta); err != nil {
+	if err := blockmeta.Write(s.logger, updir, meta); err != nil {
 		return errors.Wrap(err, "write meta file")
 	}
 	return block.Upload(ctx, s.logger, s.bucket, updir)
@@ -234,7 +236,7 @@ func (s *Shipper) sync(ctx context.Context, meta *block.Meta) (err error) {
 // iterBlockMetas calls f with the block meta for each block found in dir. It logs
 // an error and continues if it cannot access a meta.json file.
 // If f returns an error, the function returns with the same error.
-func (s *Shipper) iterBlockMetas(f func(m *block.Meta) error) error {
+func (s *Shipper) iterBlockMetas(f func(m *blockmeta.Meta) error) error {
 	names, err := fileutil.ReadDir(s.dir)
 	if err != nil {
 		return errors.Wrap(err, "read dir")
@@ -253,7 +255,7 @@ func (s *Shipper) iterBlockMetas(f func(m *block.Meta) error) error {
 		if !fi.IsDir() {
 			continue
 		}
-		m, err := block.ReadMetaFile(dir)
+		m, err := blockmeta.Read(dir)
 		if err != nil {
 			level.Warn(s.logger).Log("msg", "reading meta file failed", "err", err)
 			continue
diff --git a/pkg/store/bucket.go b/pkg/store/bucket.go
index e121e9d4081..a7de1cf9766 100644
--- a/pkg/store/bucket.go
+++ b/pkg/store/bucket.go
@@ -16,6 +16,8 @@ import (
 	"sync"
 	"time"
 
+	"github.com/improbable-eng/thanos/pkg/block/blockmeta"
+
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
 	"github.com/improbable-eng/thanos/pkg/block"
@@ -459,6 +461,7 @@ func (s *bucketSeriesSet) Err() error {
 	return s.err
 }
 
+// blockSeries return requested series from given index and chunk readers.
 func (s *BucketStore) blockSeries(
 	ctx context.Context,
 	ulid ulid.ULID,
@@ -488,7 +491,6 @@ func (s *BucketStore) blockSeries(
 	}
 
 	// Get result postings list by resolving the postings tree.
-	// TODO(bwplotka): Users are seeing panics here, because of lazyPosting being not loaded by preloadPostings.
 	ps, err := index.ExpandPostings(lazyPostings)
 	if err != nil {
 		return nil, stats, errors.Wrap(err, "expand postings")
@@ -504,7 +506,8 @@ func (s *BucketStore) blockSeries(
 		}
 	}
 
-	// Preload all series index data
+	// Preload all series index data.
+	// TODO(bwplotka): Consider not keeping all series in memory all the time.
 	if err := indexr.preloadSeries(ps); err != nil {
 		return nil, stats, errors.Wrap(err, "preload series")
 	}
@@ -1001,7 +1004,7 @@ func (s *bucketBlockSet) labelMatchers(matchers ...labels.Matcher) ([]labels.Mat
 type bucketBlock struct {
 	logger     log.Logger
 	bucket     objstore.BucketReader
-	meta       *block.Meta
+	meta       *blockmeta.Meta
 	dir        string
 	indexCache *indexCache
 	chunkPool  *pool.BytesPool
@@ -1065,7 +1068,7 @@ func (b *bucketBlock) loadMeta(ctx context.Context, id ulid.ULID) error {
 	} else if err != nil {
 		return err
 	}
-	meta, err := block.ReadMetaFile(b.dir)
+	meta, err := blockmeta.Read(b.dir)
 	if err != nil {
 		return errors.Wrap(err, "read meta.json")
 	}
@@ -1095,19 +1098,15 @@ func (b *bucketBlock) loadIndexCache(ctx context.Context) (err error) {
 		}
 	}()
 
-	indexr, err := index.NewFileReader(fn)
-	if err != nil {
-		return errors.Wrap(err, "open index reader")
-	}
-	defer runutil.CloseWithLogOnErr(b.logger, indexr, "load index cache reader")
+	// Create index cache adhoc.
 
-	if err := block.WriteIndexCache(b.logger, cachefn, indexr); err != nil {
+	if err := block.WriteIndexCache(b.logger, fn, cachefn); err != nil {
 		return errors.Wrap(err, "write index cache")
 	}
 
 	b.indexVersion, b.symbols, b.lvals, b.postings, err = block.ReadIndexCache(b.logger, cachefn)
 	if err != nil {
-		return errors.Wrap(err, "read index cache")
+		return errors.Wrap(err, "read fresh index cache")
 	}
 	return nil
 }
@@ -1179,15 +1178,22 @@ func newBucketIndexReader(ctx context.Context, logger log.Logger, block *bucketB
 		logger:       logger,
 		ctx:          ctx,
 		block:        block,
-		dec:          &index.Decoder{},
 		stats:        &queryStats{},
 		cache:        cache,
 		loadedSeries: map[uint64][]byte{},
 	}
-	r.dec.SetSymbolTable(r.block.symbols)
+	r.dec = &index.Decoder{LookupSymbol: r.lookupSymbol}
 	return r
 }
 
+func (r *bucketIndexReader) lookupSymbol(o uint32) (string, error) {
+	s, ok := r.block.symbols[o]
+	if !ok {
+		return "", errors.Errorf("bucketIndexReader: unknown symbol offset %d", o)
+	}
+	return s, nil
+}
+
 func (r *bucketIndexReader) preloadPostings() error {
 	const maxGapSize = 512 * 1024
 
@@ -1270,23 +1276,24 @@ func (r *bucketIndexReader) loadPostings(ctx context.Context, postings []*lazyPo
 	return nil
 }
 
-func (r *bucketIndexReader) preloadSeries(ids []uint64) error {
+func (r *bucketIndexReader) preloadSeries(refs []uint64) error {
 	const maxSeriesSize = 64 * 1024
 	const maxGapSize = 512 * 1024
 
-	var newIDs []uint64
+	var newRefs []uint64
 
-	for _, id := range ids {
-		if b, ok := r.cache.series(r.block.meta.ULID, id); ok {
-			r.loadedSeries[id] = b
+	for _, ref := range refs {
+		if b, ok := r.cache.series(r.block.meta.ULID, ref); ok {
+			r.loadedSeries[ref] = b
 			continue
 		}
-		newIDs = append(newIDs, id)
+		newRefs = append(newRefs, ref)
 	}
-	ids = newIDs
+	refs = newRefs
 
-	parts := partitionRanges(len(ids), func(i int) (start, end uint64) {
-		return ids[i], ids[i] + maxSeriesSize
+	// Combine multiple close byte ranges to not be rate-limited from object storage.
+	parts := partitionRanges(len(refs), func(i int) (start, end uint64) {
+		return refs[i], refs[i] + maxSeriesSize
 	}, maxGapSize)
 	var g run.Group
 
@@ -1295,7 +1302,7 @@ func (r *bucketIndexReader) preloadSeries(ids []uint64) error {
 		i, j := p[0], p[1]
 
 		g.Add(func() error {
-			return r.loadSeries(ctx, ids[i:j], ids[i], ids[j-1]+maxSeriesSize)
+			return r.loadSeries(ctx, refs[i:j], refs[i], refs[j-1]+maxSeriesSize)
 		}, func(err error) {
 			if err != nil {
 				cancel()
@@ -1305,7 +1312,7 @@ func (r *bucketIndexReader) preloadSeries(ids []uint64) error {
 	return g.Run()
 }
 
-func (r *bucketIndexReader) loadSeries(ctx context.Context, ids []uint64, start, end uint64) error {
+func (r *bucketIndexReader) loadSeries(ctx context.Context, refs []uint64, start, end uint64) error {
 	begin := time.Now()
 
 	b, err := r.block.readIndexRange(ctx, int64(start), int64(end-start))
@@ -1317,12 +1324,12 @@ func (r *bucketIndexReader) loadSeries(ctx context.Context, ids []uint64, start,
 	defer r.mtx.Unlock()
 
 	r.stats.seriesFetchCount++
-	r.stats.seriesFetched += len(ids)
+	r.stats.seriesFetched += len(refs)
 	r.stats.seriesFetchDurationSum += time.Since(begin)
 	r.stats.seriesFetchedSizeSum += int(end - start)
 
-	for _, id := range ids {
-		c := b[id-start:]
+	for _, ref := range refs {
+		c := b[ref-start:]
 
 		l, n := binary.Uvarint(c)
 		if n < 1 {
@@ -1332,8 +1339,8 @@ func (r *bucketIndexReader) loadSeries(ctx context.Context, ids []uint64, start,
 			return errors.Errorf("invalid remaining size %d, expected %d", len(c), n+int(l))
 		}
 		c = c[n : n+int(l)]
-		r.loadedSeries[id] = c
-		r.cache.setSeries(r.block.meta.ULID, id, c)
+		r.loadedSeries[ref] = c
+		r.cache.setSeries(r.block.meta.ULID, ref, c)
 	}
 	return nil
 }
@@ -1421,6 +1428,7 @@ func (r *bucketIndexReader) SortedPostings(p index.Postings) index.Postings {
 // Series populates the given labels and chunk metas for the series identified
 // by the reference.
 // Returns ErrNotFound if the ref does not resolve to a known series.
+// prealoadSeries needs to be invoked first to have this method return loaded results.
 func (r *bucketIndexReader) Series(ref uint64, lset *labels.Labels, chks *[]chunks.Meta) error {
 	b, ok := r.loadedSeries[ref]
 	if !ok {
@@ -1438,6 +1446,11 @@ func (r *bucketIndexReader) LabelIndices() ([][]string, error) {
 	return nil, errors.New("not implemented")
 }
 
+// LabelNames returns all the unique label names present in the index in sorted order.
+func (r *bucketIndexReader) LabelNames() ([]string, error) {
+	return nil, errors.New("not implemented")
+}
+
 // Close released the underlying resources of the reader.
 func (r *bucketIndexReader) Close() error {
 	r.block.pendingReaders.Done()
diff --git a/pkg/store/bucket_profile_test.go b/pkg/store/bucket_profile_test.go
new file mode 100644
index 00000000000..942231418f8
--- /dev/null
+++ b/pkg/store/bucket_profile_test.go
@@ -0,0 +1,408 @@
+package store
+
+import (
+	"context"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"runtime"
+	"runtime/pprof"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/oklog/ulid"
+
+	"github.com/improbable-eng/thanos/pkg/objstore/inmem"
+
+	"github.com/go-kit/kit/log"
+	"github.com/improbable-eng/thanos/pkg/block"
+	"github.com/improbable-eng/thanos/pkg/runutil"
+	"github.com/improbable-eng/thanos/pkg/store/storepb"
+	"github.com/improbable-eng/thanos/pkg/testutil"
+	"github.com/pkg/errors"
+	"github.com/prometheus/prometheus/pkg/timestamp"
+	"github.com/prometheus/tsdb/labels"
+)
+
+func saveHeap(t *testing.T, name string) {
+	time.Sleep(500 * time.Millisecond)
+	runtime.GC()
+	f, err := os.OpenFile("heap-"+name, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, os.ModePerm)
+	testutil.Ok(t, err)
+
+	defer f.Close()
+	testutil.Ok(t, pprof.WriteHeapProfile(f))
+}
+
+func TestBucketStore_PROFILE(t *testing.T) {
+	bkt := inmem.NewBucket()
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	dir, err := ioutil.TempDir("", "test_bucketstore_e2e")
+	testutil.Ok(t, err)
+	//defer func() { testutil.Ok(t, os.RemoveAll(dir)) }()
+
+	series := []labels.Labels{
+		labels.FromStrings("a", "1", "b", "1"),
+		labels.FromStrings("a", "1", "b", "2"),
+		labels.FromStrings("a", "2", "b", "1"),
+		labels.FromStrings("a", "2", "b", "2"),
+		labels.FromStrings("a", "1", "c", "1"),
+		labels.FromStrings("a", "1", "c", "2"),
+		labels.FromStrings("a", "2", "c", "1"),
+		labels.FromStrings("a", "2", "c", "2"),
+	}
+	extLset := labels.FromStrings("ext1", "value1")
+
+	start := time.Now()
+	now := start
+
+	var ids []ulid.ULID
+	for i := 0; i < 3; i++ {
+		mint := timestamp.FromTime(now)
+		now = now.Add(2 * time.Hour)
+		maxt := timestamp.FromTime(now)
+
+		// Create two blocks per time slot. Only add 10 samples each so only one chunk
+		// gets created each. This way we can easily verify we got 10 chunks per series below.
+		id1, err := testutil.CreateBlock(dir, series[:4], 10, mint, maxt, extLset, 0)
+		testutil.Ok(t, err)
+		id2, err := testutil.CreateBlock(dir, series[4:], 10, mint, maxt, extLset, 0)
+		testutil.Ok(t, err)
+
+		ids = append(ids, id1, id2)
+		dir1, dir2 := filepath.Join(dir, id1.String()), filepath.Join(dir, id2.String())
+
+		// Add labels to the meta of the second block.
+		meta, err := block.ReadMetaFile(dir2)
+		testutil.Ok(t, err)
+		meta.Thanos.Labels = map[string]string{"ext2": "value2"}
+		testutil.Ok(t, block.WriteMetaFile(log.NewNopLogger(), dir2, meta))
+
+		testutil.Ok(t, block.Upload(ctx, log.NewNopLogger(), bkt, dir1))
+		testutil.Ok(t, block.Upload(ctx, log.NewNopLogger(), bkt, dir2))
+
+		testutil.Ok(t, os.RemoveAll(dir1))
+		testutil.Ok(t, os.RemoveAll(dir2))
+	}
+
+	store, err := NewBucketStore(nil, nil, bkt, dir, 100, 0, false)
+	testutil.Ok(t, err)
+
+	ctx, _ = context.WithTimeout(ctx, 30*time.Second)
+
+	if err := runutil.Retry(100*time.Millisecond, ctx.Done(), func() error {
+		if err := store.SyncBlocks(ctx); err != nil {
+			return err
+		}
+		if store.numBlocks() < 6 {
+			return errors.New("not all blocks loaded")
+		}
+		return nil
+	}); err != nil && errors.Cause(err) != context.Canceled {
+		t.Error(err)
+		t.FailNow()
+	}
+	testutil.Ok(t, err)
+
+	pbseries := [][]storepb.Label{
+		{{Name: "a", Value: "1"}, {Name: "b", Value: "1"}, {Name: "ext1", Value: "value1"}},
+		{{Name: "a", Value: "1"}, {Name: "b", Value: "2"}, {Name: "ext1", Value: "value1"}},
+		{{Name: "a", Value: "1"}, {Name: "c", Value: "1"}, {Name: "ext2", Value: "value2"}},
+		{{Name: "a", Value: "1"}, {Name: "c", Value: "2"}, {Name: "ext2", Value: "value2"}},
+		{{Name: "a", Value: "2"}, {Name: "b", Value: "1"}, {Name: "ext1", Value: "value1"}},
+		{{Name: "a", Value: "2"}, {Name: "b", Value: "2"}, {Name: "ext1", Value: "value1"}},
+		{{Name: "a", Value: "2"}, {Name: "c", Value: "1"}, {Name: "ext2", Value: "value2"}},
+		{{Name: "a", Value: "2"}, {Name: "c", Value: "2"}, {Name: "ext2", Value: "value2"}},
+	}
+
+	srv := newStoreSeriesServer(ctx)
+
+	err = store.Series(&storepb.SeriesRequest{
+		Matchers: []storepb.LabelMatcher{
+			{Type: storepb.LabelMatcher_RE, Name: "a", Value: "1|2"},
+		},
+		MinTime: timestamp.FromTime(start),
+		MaxTime: timestamp.FromTime(now),
+	}, srv)
+	testutil.Ok(t, err)
+	testutil.Equals(t, len(pbseries), len(srv.SeriesSet))
+
+	g := sync.WaitGroup{}
+
+	// NO REPRO
+	go func() {
+		g.Add(1)
+		time.Sleep(10 * time.Millisecond)
+		// Simulate deleted blocks without sync (compaction!)
+		testutil.Ok(t, block.Delete(ctx, bkt, ids[2]))
+		time.Sleep(10 * time.Millisecond)
+		store.SyncBlocks(ctx)
+		store.SyncBlocks(ctx)
+
+		g.Done()
+	}()
+
+	for i := 0; i < 1000; i++ {
+		go func() {
+			g.Add(1)
+			srv := newStoreSeriesServer(ctx)
+
+			err = store.Series(&storepb.SeriesRequest{
+				Matchers: []storepb.LabelMatcher{
+					{Type: storepb.LabelMatcher_RE, Name: "a", Value: "1|2"},
+				},
+				MinTime: timestamp.FromTime(start),
+				MaxTime: timestamp.FromTime(now),
+			}, srv)
+			fmt.Println(err)
+			//testutil.Ok(t, err)
+			//testutil.Equals(t, len(pbseries), len(srv.SeriesSet))
+
+			g.Done()
+		}()
+	}
+	time.Sleep(10 * time.Millisecond)
+	for i := 0; i < 1000; i++ {
+		go func() {
+			g.Add(1)
+			srv := newStoreSeriesServer(ctx)
+
+			err = store.Series(&storepb.SeriesRequest{
+				Matchers: []storepb.LabelMatcher{
+					{Type: storepb.LabelMatcher_RE, Name: "a", Value: "1|2"},
+				},
+				MinTime: timestamp.FromTime(start),
+				MaxTime: timestamp.FromTime(now),
+			}, srv)
+			fmt.Println(err)
+			//testutil.Ok(t, err)
+			//testutil.Equals(t, len(pbseries), len(srv.SeriesSet))
+
+			g.Done()
+		}()
+	}
+
+	g.Wait()
+
+	//for i, s := range srv.SeriesSet {
+	//	testutil.Equals(t, pbseries[i], s.Labels)
+	//	testutil.Equals(t, 3, len(s.Chunks))
+	//}
+
+	saveHeap(t, "2")
+}
+
+/*
+==================
+WARNING: DATA RACE
+Read at 0x00c4201c22f8 by goroutine 75:
+  github.com/improbable-eng/thanos/pkg/pool.(*BytesPool).Put()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/pool/pool.go:83 +0x14c
+  github.com/improbable-eng/thanos/pkg/store.(*bucketChunkReader).Close()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket.go:1570 +0x115
+  github.com/improbable-eng/thanos/pkg/runutil.CloseWithLogOnErr()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/runutil/runutil.go:60 +0x59
+  github.com/improbable-eng/thanos/pkg/store.(*BucketStore).Series()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket.go:811 +0x2d7e
+  github.com/improbable-eng/thanos/pkg/store.TestBucketStore_PROFILE.func2()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket_profile_test.go:140 +0x4e6
+
+Previous write at 0x00c4201c22f8 by goroutine 25:
+  sync/atomic.AddInt64()
+      /usr/local/go/src/runtime/race_amd64.s:276 +0xb
+  github.com/improbable-eng/thanos/pkg/pool.(*BytesPool).Get()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/pool/pool.go:65 +0x1ad
+  github.com/improbable-eng/thanos/pkg/store.(*bucketBlock).readChunkRange()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket.go:1130 +0x95
+  github.com/improbable-eng/thanos/pkg/store.(*bucketChunkReader).loadChunks()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket.go:1499 +0xe7
+  github.com/improbable-eng/thanos/pkg/store.(*bucketChunkReader).preload.func3()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket.go:1485 +0x23a
+  github.com/improbable-eng/thanos/vendor/github.com/oklog/run.(*Group).Run.func1()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/vendor/github.com/oklog/run/group.go:38 +0x34
+
+Goroutine 75 (running) created at:
+  github.com/improbable-eng/thanos/pkg/store.TestBucketStore_PROFILE()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket_profile_test.go:136 +0x238e
+  testing.tRunner()
+      /usr/local/go/src/testing/testing.go:777 +0x16d
+
+Goroutine 25 (finished) created at:
+  github.com/improbable-eng/thanos/vendor/github.com/oklog/run.(*Group).Run()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/vendor/github.com/oklog/run/group.go:37 +0x10b
+  github.com/improbable-eng/thanos/pkg/store.(*bucketChunkReader).preload()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket.go:1493 +0x6f0
+  github.com/improbable-eng/thanos/pkg/store.(*BucketStore).blockSeries()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket.go:572 +0x1109
+  github.com/improbable-eng/thanos/pkg/store.(*BucketStore).Series.func1()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket.go:721 +0x1e7
+  github.com/improbable-eng/thanos/vendor/github.com/oklog/run.(*Group).Run.func1()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/vendor/github.com/oklog/run/group.go:38 +0x34
+==================
+<nil>
+==================
+WARNING: DATA RACE
+Write at 0x00c42029c2fc by goroutine 10:
+  internal/race.Write()
+      /usr/local/go/src/internal/race/race.go:41 +0x38
+  sync.(*WaitGroup).Wait()
+      /usr/local/go/src/sync/waitgroup.go:127 +0xf3
+  github.com/improbable-eng/thanos/pkg/store.TestBucketStore_PROFILE()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket_profile_test.go:164 +0x2442
+  testing.tRunner()
+      /usr/local/go/src/testing/testing.go:777 +0x16d
+
+Previous read at 0x00c42029c2fc by goroutine 74:
+  internal/race.Read()
+      /usr/local/go/src/internal/race/race.go:37 +0x38
+  sync.(*WaitGroup).Add()
+      /usr/local/go/src/sync/waitgroup.go:70 +0x16e
+  github.com/improbable-eng/thanos/pkg/store.TestBucketStore_PROFILE.func2()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket_profile_test.go:137 +0x5c
+
+Goroutine 10 (running) created at:
+  testing.(*T).Run()
+      /usr/local/go/src/testing/testing.go:824 +0x564
+  testing.runTests.func1()
+      /usr/local/go/src/testing/testing.go:1063 +0xa4
+  testing.tRunner()
+      /usr/local/go/src/testing/testing.go:777 +0x16d
+  testing.runTests()
+      /usr/local/go/src/testing/testing.go:1061 +0x4e1
+  testing.(*M).Run()
+      /usr/local/go/src/testing/testing.go:978 +0x2cd
+  main.main()
+      _testmain.go:70 +0x22a
+
+Goroutine 74 (running) created at:
+  github.com/improbable-eng/thanos/pkg/store.TestBucketStore_PROFILE()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket_profile_test.go:136 +0x238e
+  testing.tRunner()
+      /usr/local/go/src/testing/testing.go:777 +0x16d
+==================
+==================
+WARNING: DATA RACE
+Write at 0x00c4202647b0 by goroutine 230:
+  runtime.mapdelete_faststr()
+      /usr/local/go/src/runtime/hashmap_fast.go:883 +0x0
+  github.com/improbable-eng/thanos/pkg/objstore/inmem.(*Bucket).Delete()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/objstore/inmem/inmem.go:138 +0x69
+  github.com/improbable-eng/thanos/pkg/objstore.DeleteDir.func1()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/objstore/objstore.go:102 +0x113
+  github.com/improbable-eng/thanos/pkg/objstore/inmem.(*Bucket).Iter()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/objstore/inmem/inmem.go:76 +0x616
+  github.com/improbable-eng/thanos/pkg/objstore.DeleteDir()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/objstore/objstore.go:97 +0x10c
+  github.com/improbable-eng/thanos/pkg/block.Delete()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/block/block.go:215 +0x7f
+  github.com/improbable-eng/thanos/pkg/store.TestBucketStore_PROFILE.func3()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket_profile_test.go:157 +0xae
+
+Previous read at 0x00c4202647b0 by goroutine 85:
+  runtime.mapaccess2_faststr()
+      /usr/local/go/src/runtime/hashmap_fast.go:261 +0x0
+  github.com/improbable-eng/thanos/pkg/objstore/inmem.(*Bucket).GetRange()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/objstore/inmem/inmem.go:103 +0x9b
+  github.com/improbable-eng/thanos/pkg/store.(*bucketBlock).readChunkRange()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket.go:1136 +0x255
+  github.com/improbable-eng/thanos/pkg/store.(*bucketChunkReader).loadChunks()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket.go:1499 +0xe7
+  github.com/improbable-eng/thanos/pkg/store.(*bucketChunkReader).preload.func3()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket.go:1485 +0x23a
+  github.com/improbable-eng/thanos/vendor/github.com/oklog/run.(*Group).Run.func1()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/vendor/github.com/oklog/run/group.go:38 +0x34
+
+Goroutine 230 (running) created at:
+  github.com/improbable-eng/thanos/pkg/store.TestBucketStore_PROFILE()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket_profile_test.go:154 +0x2431
+  testing.tRunner()
+      /usr/local/go/src/testing/testing.go:777 +0x16d
+
+Goroutine 85 (finished) created at:
+  github.com/improbable-eng/thanos/vendor/github.com/oklog/run.(*Group).Run()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/vendor/github.com/oklog/run/group.go:37 +0x10b
+  github.com/improbable-eng/thanos/pkg/store.(*bucketChunkReader).preload()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket.go:1493 +0x6f0
+  github.com/improbable-eng/thanos/pkg/store.(*BucketStore).blockSeries()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket.go:572 +0x1109
+  github.com/improbable-eng/thanos/pkg/store.(*BucketStore).Series.func1()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket.go:721 +0x1e7
+  github.com/improbable-eng/thanos/vendor/github.com/oklog/run.(*Group).Run.func1()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/vendor/github.com/oklog/run/group.go:38 +0x34
+==================
+==================
+WARNING: DATA RACE
+Read at 0x00c4200d4978 by goroutine 76:
+  github.com/improbable-eng/thanos/pkg/pool.(*BytesPool).Put()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/pool/pool.go:83 +0x14c
+  github.com/improbable-eng/thanos/pkg/store.(*bucketChunkReader).Close()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket.go:1570 +0x115
+  github.com/improbable-eng/thanos/pkg/runutil.CloseWithLogOnErr()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/runutil/runutil.go:60 +0x59
+  github.com/improbable-eng/thanos/pkg/store.(*BucketStore).Series()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket.go:811 +0x2d7e
+  github.com/improbable-eng/thanos/pkg/store.TestBucketStore_PROFILE.func2()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket_profile_test.go:140 +0x4e6
+
+Previous write at 0x00c4200d4978 by goroutine 365:
+  sync/atomic.AddInt64()
+      /usr/local/go/src/runtime/race_amd64.s:276 +0xb
+  github.com/improbable-eng/thanos/pkg/pool.(*BytesPool).Get()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/pool/pool.go:65 +0x1ad
+  github.com/improbable-eng/thanos/pkg/store.(*bucketBlock).readChunkRange()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket.go:1130 +0x95
+  github.com/improbable-eng/thanos/pkg/store.(*bucketChunkReader).loadChunks()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket.go:1499 +0xe7
+  github.com/improbable-eng/thanos/pkg/store.(*bucketChunkReader).preload.func3()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket.go:1485 +0x23a
+  github.com/improbable-eng/thanos/vendor/github.com/oklog/run.(*Group).Run.func1()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/vendor/github.com/oklog/run/group.go:38 +0x34
+
+Goroutine 76 (running) created at:
+  github.com/improbable-eng/thanos/pkg/store.TestBucketStore_PROFILE()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket_profile_test.go:136 +0x238e
+  testing.tRunner()
+      /usr/local/go/src/testing/testing.go:777 +0x16d
+
+Goroutine 365 (finished) created at:
+  github.com/improbable-eng/thanos/vendor/github.com/oklog/run.(*Group).Run()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/vendor/github.com/oklog/run/group.go:37 +0x10b
+  github.com/improbable-eng/thanos/pkg/store.(*bucketChunkReader).preload()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket.go:1493 +0x6f0
+  github.com/improbable-eng/thanos/pkg/store.(*BucketStore).blockSeries()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket.go:572 +0x1109
+  github.com/improbable-eng/thanos/pkg/store.(*BucketStore).Series.func1()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket.go:721 +0x1e7
+  github.com/improbable-eng/thanos/vendor/github.com/oklog/run.(*Group).Run.func1()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/vendor/github.com/oklog/run/group.go:38 +0x34
+==================
+<nil>
+==================
+WARNING: DATA RACE
+Write at 0x00c4200837d0 by goroutine 77:
+  github.com/improbable-eng/thanos/pkg/store.TestBucketStore_PROFILE.func2()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket_profile_test.go:140 +0x50b
+
+Previous write at 0x00c4200837d0 by goroutine 76:
+  github.com/improbable-eng/thanos/pkg/store.TestBucketStore_PROFILE.func2()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket_profile_test.go:140 +0x50b
+
+Goroutine 77 (running) created at:
+  github.com/improbable-eng/thanos/pkg/store.TestBucketStore_PROFILE()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket_profile_test.go:136 +0x238e
+  testing.tRunner()
+      /usr/local/go/src/testing/testing.go:777 +0x16d
+
+Goroutine 76 (finished) created at:
+  github.com/improbable-eng/thanos/pkg/store.TestBucketStore_PROFILE()
+      /home/bartek/Repos/thanosGo/src/github.com/improbable-eng/thanos/pkg/store/bucket_profile_test.go:136 +0x238e
+  testing.tRunner()
+      /usr/local/go/src/testing/testing.go:777 +0x16d
+==================
+
+*/
diff --git a/pkg/testutil/prometheus.go b/pkg/testutil/prometheus.go
index 807b61f8a05..6c5729531b8 100644
--- a/pkg/testutil/prometheus.go
+++ b/pkg/testutil/prometheus.go
@@ -12,8 +12,9 @@ import (
 	"syscall"
 	"time"
 
+	"github.com/improbable-eng/thanos/pkg/block/blockmeta"
+
 	"github.com/go-kit/kit/log"
-	"github.com/improbable-eng/thanos/pkg/block"
 	"github.com/improbable-eng/thanos/pkg/runutil"
 	"github.com/oklog/ulid"
 	"github.com/pkg/errors"
@@ -188,7 +189,7 @@ func CreateBlock(
 	extLset labels.Labels,
 	resolution int64,
 ) (id ulid.ULID, err error) {
-	h, err := tsdb.NewHead(nil, nil, tsdb.NopWAL(), 10000000000)
+	h, err := tsdb.NewHead(nil, nil, nil, 10000000000)
 	if err != nil {
 		return id, errors.Wrap(err, "create head block")
 	}
@@ -238,15 +239,15 @@ func CreateBlock(
 		return id, errors.Wrap(err, "create compactor")
 	}
 
-	id, err = c.Write(dir, h, mint, maxt)
+	id, err = c.Write(dir, h, mint, maxt, nil)
 	if err != nil {
 		return id, errors.Wrap(err, "write block")
 	}
 
-	if _, err = block.InjectThanosMeta(log.NewNopLogger(), filepath.Join(dir, id.String()), block.ThanosMeta{
+	if _, err = blockmeta.InjectThanos(log.NewNopLogger(), filepath.Join(dir, id.String()), blockmeta.Thanos{
 		Labels:     extLset.Map(),
-		Downsample: block.ThanosDownsampleMeta{Resolution: resolution},
-		Source:     block.TestSource,
+		Downsample: blockmeta.ThanosDownsample{Resolution: resolution},
+		Source:     blockmeta.TestSource,
 	}, nil); err != nil {
 		return id, errors.Wrap(err, "finalize block")
 	}
diff --git a/pkg/verifier/index_issue.go b/pkg/verifier/index_issue.go
index 54a20703d45..3e96ccb2062 100644
--- a/pkg/verifier/index_issue.go
+++ b/pkg/verifier/index_issue.go
@@ -8,6 +8,8 @@ import (
 	"path"
 	"path/filepath"
 
+	"github.com/improbable-eng/thanos/pkg/block/blockmeta"
+
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
 	"github.com/improbable-eng/thanos/pkg/block"
@@ -94,7 +96,7 @@ func IndexIssue(ctx context.Context, logger log.Logger, bkt objstore.Bucket, bac
 			logger,
 			tmpdir,
 			id,
-			block.BucketRepairSource,
+			blockmeta.BucketRepairSource,
 			block.IgnoreCompleteOutsideChunk,
 			block.IgnoreDuplicateOutsideChunk,
 			block.IgnoreIssue347OutsideChunk,