Vendor tsdb 0.10.0

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

go.mod

@@ -38,7 +38,7 @@ require (
 	github.com/prometheus/client_golang v1.0.0
 	github.com/prometheus/client_model v0.0.0-20190129233127-fd36f4220a90
 	github.com/prometheus/common v0.4.1
-	github.com/prometheus/tsdb v0.9.1
+	github.com/prometheus/tsdb v0.10.0
 	github.com/samuel/go-zookeeper v0.0.0-20161028232340-1d7be4effb13
 	github.com/shurcooL/httpfs v0.0.0-20171119174359-809beceb2371
 	github.com/shurcooL/vfsgen v0.0.0-20180825020608-02ddb050ef6b

go.sum

@@ -286,8 +286,8 @@ github.com/prometheus/procfs v0.0.0-20190117184657-bf6a532e95b1/go.mod h1:c3At6R
 github.com/prometheus/procfs v0.0.2 h1:6LJUbpNm42llc4HRCuvApCSWB/WfhuNo9K98Q9sNGfs=
 github.com/prometheus/procfs v0.0.2/go.mod h1:TjEm7ze935MbeOT/UhFTIMYKhuLP4wbCsTZCD3I8kEA=
 github.com/prometheus/prometheus v0.0.0-20180315085919-58e2a31db8de/go.mod h1:oAIUtOny2rjMX0OWN5vPR5/q/twIROJvdqnQKDdil/s=
-github.com/prometheus/tsdb v0.9.1 h1:IWaAmWkYlgG7/S4iw4IpAQt5Y35QaZM6/GsZ7GsjAuk=
+github.com/prometheus/tsdb v0.10.0 h1:If5rVCMTp6W2SiRAQFlbpJNgVlgMEd+U2GZckwK38ic=
-github.com/prometheus/tsdb v0.9.1/go.mod h1:oi49uRhEe9dPUTlS3JRZOwJuVi6tmh10QSgwXEyGCt4=
+github.com/prometheus/tsdb v0.10.0/go.mod h1:oi49uRhEe9dPUTlS3JRZOwJuVi6tmh10QSgwXEyGCt4=
 github.com/rcrowley/go-metrics v0.0.0-20181016184325-3113b8401b8a/go.mod h1:bCqnVzQkZxMG4s8nGwiZ5l3QUCyqpo9Y+/ZMZ9VjZe4=
 github.com/rogpeppe/fastuuid v0.0.0-20150106093220-6724a57986af/go.mod h1:XWv6SoW27p1b0cqNHllgS5HIMJraePCO15w5zCzIWYg=
 github.com/rs/cors v1.6.0/go.mod h1:gFx+x8UowdsKA9AchylcLynDq+nNFfI8FkUZdN/jGCU=

vendor/github.com/prometheus/tsdb/CHANGELOG.md

@@ -1,4 +1,11 @@
-## Master / unreleased
+## master / unreleased
+
+## 0.10.0
+
+ - [FEATURE] Added `DBReadOnly` to allow opening a database in read only mode.
+    - `DBReadOnly.Blocks()` exposes a slice of `BlockReader`s.
+    - `BlockReader` interface - removed MinTime/MaxTime methods and now exposes the full block meta via `Meta()`.
+ - [FEATURE] `chunckenc.Chunk.Iterator` method now takes a `chunckenc.Iterator` interface as an argument for reuse.
 
 ## 0.9.1
 
@@ -19,6 +26,7 @@
  - [ENHANCEMENT] Reduced disk usage for WAL for small setups.
  - [ENHANCEMENT] Optimize queries using regexp for set lookups.
 
+
 ## 0.8.0
 
  - [BUGFIX] Calling `Close` more than once on a querier returns an error instead of a panic.

vendor/github.com/prometheus/tsdb/Makefile.common

@@ -74,7 +74,7 @@ PROMU_URL     := https://github.com/prometheus/promu/releases/download/v$(PROMU_
 
 GOLANGCI_LINT :=
 GOLANGCI_LINT_OPTS ?=
-GOLANGCI_LINT_VERSION ?= v1.16.0
+GOLANGCI_LINT_VERSION ?= v1.17.1
 # golangci-lint only supports linux, darwin and windows platforms on i386/amd64.
 # windows isn't included here because of the path separator being different.
 ifeq ($(GOHOSTOS),$(filter $(GOHOSTOS),linux darwin))

vendor/github.com/prometheus/tsdb/block.go

@@ -138,11 +138,8 @@ type BlockReader interface {
 	// Tombstones returns a TombstoneReader over the block's deleted data.
 	Tombstones() (TombstoneReader, error)
 
-	// MinTime returns the min time of the block.
+	// Meta provides meta information about the block reader.
-	MinTime() int64
+	Meta() BlockMeta
-
-	// MaxTime returns the max time of the block.
-	MaxTime() int64
 }
 
 // Appendable defines an entity to which data can be appended.

vendor/github.com/prometheus/tsdb/chunkenc/chunk.go

@@ -44,7 +44,10 @@ type Chunk interface {
 	Bytes() []byte
 	Encoding() Encoding
 	Appender() (Appender, error)
-	Iterator() Iterator
+	// The iterator passed as argument is for re-use.
+	// Depending on implementation, the iterator can
+	// be re-used or a new iterator can be allocated.
+	Iterator(Iterator) Iterator
 	NumSamples() int
 }
 

vendor/github.com/prometheus/tsdb/chunkenc/xor.go

@@ -77,7 +77,7 @@ func (c *XORChunk) NumSamples() int {
 
 // Appender implements the Chunk interface.
 func (c *XORChunk) Appender() (Appender, error) {
-	it := c.iterator()
+	it := c.iterator(nil)
 
 	// To get an appender we must know the state it would have if we had
 	// appended all existing data from scratch.
@@ -102,19 +102,25 @@ func (c *XORChunk) Appender() (Appender, error) {
 	return a, nil
 }
 
-func (c *XORChunk) iterator() *xorIterator {
+func (c *XORChunk) iterator(it Iterator) *xorIterator {
 	// Should iterators guarantee to act on a copy of the data so it doesn't lock append?
 	// When using striped locks to guard access to chunks, probably yes.
 	// Could only copy data if the chunk is not completed yet.
+	if xorIter, ok := it.(*xorIterator); ok {
+		xorIter.Reset(c.b.bytes())
+		return xorIter
+	}
 	return &xorIterator{
+		// The first 2 bytes contain chunk headers.
+		// We skip that for actual samples.
 		br:       newBReader(c.b.bytes()[2:]),
 		numTotal: binary.BigEndian.Uint16(c.b.bytes()),
 	}
 }
 
 // Iterator implements the Chunk interface.
-func (c *XORChunk) Iterator() Iterator {
+func (c *XORChunk) Iterator(it Iterator) Iterator {
-	return c.iterator()
+	return c.iterator(it)
 }
 
 type xorAppender struct {
@@ -243,6 +249,21 @@ func (it *xorIterator) Err() error {
 	return it.err
 }
 
+func (it *xorIterator) Reset(b []byte) {
+	// The first 2 bytes contain chunk headers.
+	// We skip that for actual samples.
+	it.br = newBReader(b[2:])
+	it.numTotal = binary.BigEndian.Uint16(b)
+
+	it.numRead = 0
+	it.t = 0
+	it.val = 0
+	it.leading = 0
+	it.trailing = 0
+	it.tDelta = 0
+	it.err = nil
+}
+
 func (it *xorIterator) Next() bool {
 	if it.err != nil || it.numRead == it.numTotal {
 		return false

vendor/github.com/prometheus/tsdb/chunks/chunks.go

@@ -57,8 +57,9 @@ type Meta struct {
 }
 
 // writeHash writes the chunk encoding and raw data into the provided hash.
-func (cm *Meta) writeHash(h hash.Hash) error {
+func (cm *Meta) writeHash(h hash.Hash, buf []byte) error {
-	if _, err := h.Write([]byte{byte(cm.Chunk.Encoding())}); err != nil {
+	buf = append(buf[:0], byte(cm.Chunk.Encoding()))
+	if _, err := h.Write(buf[:1]); err != nil {
 		return err
 	}
 	if _, err := h.Write(cm.Chunk.Bytes()); err != nil {
@@ -97,6 +98,7 @@ type Writer struct {
 	wbuf    *bufio.Writer
 	n       int64
 	crc32   hash.Hash
+	buf     [binary.MaxVarintLen32]byte
 
 	segmentSize int64
 }
@@ -245,8 +247,8 @@ func MergeChunks(a, b chunkenc.Chunk) (*chunkenc.XORChunk, error) {
 	if err != nil {
 		return nil, err
 	}
-	ait := a.Iterator()
+	ait := a.Iterator(nil)
-	bit := b.Iterator()
+	bit := b.Iterator(nil)
 	aok, bok := ait.Next(), bit.Next()
 	for aok && bok {
 		at, av := ait.At()
@@ -299,22 +301,19 @@ func (w *Writer) WriteChunks(chks ...Meta) error {
 		}
 	}
 
-	var (
+	var seq = uint64(w.seq()) << 32
-		b   = [binary.MaxVarintLen32]byte{}
-		seq = uint64(w.seq()) << 32
-	)
 	for i := range chks {
 		chk := &chks[i]
 
 		chk.Ref = seq | uint64(w.n)
 
-		n := binary.PutUvarint(b[:], uint64(len(chk.Chunk.Bytes())))
+		n := binary.PutUvarint(w.buf[:], uint64(len(chk.Chunk.Bytes())))
 
-		if err := w.write(b[:n]); err != nil {
+		if err := w.write(w.buf[:n]); err != nil {
 			return err
 		}
-		b[0] = byte(chk.Chunk.Encoding())
+		w.buf[0] = byte(chk.Chunk.Encoding())
-		if err := w.write(b[:1]); err != nil {
+		if err := w.write(w.buf[:1]); err != nil {
 			return err
 		}
 		if err := w.write(chk.Chunk.Bytes()); err != nil {
@@ -322,10 +321,10 @@ func (w *Writer) WriteChunks(chks ...Meta) error {
 		}
 
 		w.crc32.Reset()
-		if err := chk.writeHash(w.crc32); err != nil {
+		if err := chk.writeHash(w.crc32, w.buf[:]); err != nil {
 			return err
 		}
-		if err := w.write(w.crc32.Sum(b[:0])); err != nil {
+		if err := w.write(w.crc32.Sum(w.buf[:0])); err != nil {
 			return err
 		}
 	}
@@ -366,7 +365,7 @@ func (b realByteSlice) Sub(start, end int) ByteSlice {
 	return b[start:end]
 }
 
-// Reader implements a SeriesReader for a serialized byte stream
+// Reader implements a ChunkReader for a serialized byte stream
 // of series data.
 type Reader struct {
 	bs   []ByteSlice // The underlying bytes holding the encoded series data.
@@ -503,11 +502,11 @@ func sequenceFiles(dir string) ([]string, error) {
 	return res, nil
 }
 
-func closeAll(cs []io.Closer) (err error) {
+func closeAll(cs []io.Closer) error {
+	var merr tsdb_errors.MultiError
+
 	for _, c := range cs {
-		if e := c.Close(); e != nil {
+		merr.Add(c.Close())
-			err = e
-		}
 	}
-	return err
+	return merr.Err()
 }

vendor/github.com/prometheus/tsdb/compact.go

@@ -662,7 +662,7 @@ func (c *LeveledCompactor) populateBlock(blocks []BlockReader, meta *BlockMeta,
 	}()
 	c.metrics.populatingBlocks.Set(1)
 
-	globalMaxt := blocks[0].MaxTime()
+	globalMaxt := blocks[0].Meta().MaxTime
 	for i, b := range blocks {
 		select {
 		case <-c.ctx.Done():
@@ -671,13 +671,13 @@ func (c *LeveledCompactor) populateBlock(blocks []BlockReader, meta *BlockMeta,
 		}
 
 		if !overlapping {
-			if i > 0 && b.MinTime() < globalMaxt {
+			if i > 0 && b.Meta().MinTime < globalMaxt {
 				c.metrics.overlappingBlocks.Inc()
 				overlapping = true
 				level.Warn(c.logger).Log("msg", "found overlapping blocks during compaction", "ulid", meta.ULID)
 			}
-			if b.MaxTime() > globalMaxt {
+			if b.Meta().MaxTime > globalMaxt {
-				globalMaxt = b.MaxTime()
+				globalMaxt = b.Meta().MaxTime
 			}
 		}
 
@@ -736,6 +736,7 @@ func (c *LeveledCompactor) populateBlock(blocks []BlockReader, meta *BlockMeta,
 		return errors.Wrap(err, "add symbols")
 	}
 
+	delIter := &deletedIterator{}
 	for set.Next() {
 		select {
 		case <-c.ctx.Done():
@@ -788,17 +789,18 @@ func (c *LeveledCompactor) populateBlock(blocks []BlockReader, meta *BlockMeta,
 					return err
 				}
 
-				it := &deletedIterator{it: chk.Chunk.Iterator(), intervals: dranges}
+				delIter.it = chk.Chunk.Iterator(delIter.it)
+				delIter.intervals = dranges
 
 				var (
 					t int64
 					v float64
 				)
-				for it.Next() {
+				for delIter.Next() {
-					t, v = it.At()
+					t, v = delIter.At()
 					app.Append(t, v)
 				}
-				if err := it.Err(); err != nil {
+				if err := delIter.Err(); err != nil {
 					return errors.Wrap(err, "iterate chunk while re-encoding")
 				}
 

vendor/github.com/prometheus/tsdb/db.go

@@ -250,6 +250,178 @@ func newDBMetrics(db *DB, r prometheus.Registerer) *dbMetrics {
 	return m
 }
 
+// ErrClosed is returned when the db is closed.
+var ErrClosed = errors.New("db already closed")
+
+// DBReadOnly provides APIs for read only operations on a database.
+// Current implementation doesn't support concurency so
+// all API calls should happen in the same go routine.
+type DBReadOnly struct {
+	logger  log.Logger
+	dir     string
+	closers []io.Closer
+	closed  chan struct{}
+}
+
+// OpenDBReadOnly opens DB in the given directory for read only operations.
+func OpenDBReadOnly(dir string, l log.Logger) (*DBReadOnly, error) {
+	if _, err := os.Stat(dir); err != nil {
+		return nil, errors.Wrap(err, "openning the db dir")
+	}
+
+	if l == nil {
+		l = log.NewNopLogger()
+	}
+
+	return &DBReadOnly{
+		logger: l,
+		dir:    dir,
+		closed: make(chan struct{}),
+	}, nil
+}
+
+// Querier loads the wal and returns a new querier over the data partition for the given time range.
+// Current implementation doesn't support multiple Queriers.
+func (db *DBReadOnly) Querier(mint, maxt int64) (Querier, error) {
+	select {
+	case <-db.closed:
+		return nil, ErrClosed
+	default:
+	}
+	blocksReaders, err := db.Blocks()
+	if err != nil {
+		return nil, err
+	}
+	blocks := make([]*Block, len(blocksReaders))
+	for i, b := range blocksReaders {
+		b, ok := b.(*Block)
+		if !ok {
+			return nil, errors.New("unable to convert a read only block to a normal block")
+		}
+		blocks[i] = b
+	}
+
+	head, err := NewHead(nil, db.logger, nil, 1)
+	if err != nil {
+		return nil, err
+	}
+	maxBlockTime := int64(math.MinInt64)
+	if len(blocks) > 0 {
+		maxBlockTime = blocks[len(blocks)-1].Meta().MaxTime
+	}
+
+	// Also add the WAL if the current blocks don't cover the requestes time range.
+	if maxBlockTime <= maxt {
+		w, err := wal.Open(db.logger, nil, filepath.Join(db.dir, "wal"))
+		if err != nil {
+			return nil, err
+		}
+		head, err = NewHead(nil, db.logger, w, 1)
+		if err != nil {
+			return nil, err
+		}
+		// Set the min valid time for the ingested wal samples
+		// to be no lower than the maxt of the last block.
+		if err := head.Init(maxBlockTime); err != nil {
+			return nil, errors.Wrap(err, "read WAL")
+		}
+		// Set the wal to nil to disable all wal operations.
+		// This is mainly to avoid blocking when closing the head.
+		head.wal = nil
+
+		db.closers = append(db.closers, head)
+	}
+
+	// TODO: Refactor so that it is possible to obtain a Querier without initializing a writable DB instance.
+	// Option 1: refactor DB to have the Querier implementation using the DBReadOnly.Querier implementation not the opposite.
+	// Option 2: refactor Querier to use another independent func which
+	// can than be used by a read only and writable db instances without any code duplication.
+	dbWritable := &DB{
+		dir:    db.dir,
+		logger: db.logger,
+		blocks: blocks,
+		head:   head,
+	}
+
+	return dbWritable.Querier(mint, maxt)
+}
+
+// Blocks returns a slice of block readers for persisted blocks.
+func (db *DBReadOnly) Blocks() ([]BlockReader, error) {
+	select {
+	case <-db.closed:
+		return nil, ErrClosed
+	default:
+	}
+	loadable, corrupted, err := openBlocks(db.logger, db.dir, nil, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	// Corrupted blocks that have been superseded by a loadable block can be safely ignored.
+	for _, block := range loadable {
+		for _, b := range block.Meta().Compaction.Parents {
+			delete(corrupted, b.ULID)
+		}
+	}
+	if len(corrupted) > 0 {
+		for _, b := range loadable {
+			if err := b.Close(); err != nil {
+				level.Warn(db.logger).Log("msg", "closing a block", err)
+			}
+		}
+		return nil, errors.Errorf("unexpected corrupted block:%v", corrupted)
+	}
+
+	if len(loadable) == 0 {
+		return nil, errors.New("no blocks found")
+	}
+
+	sort.Slice(loadable, func(i, j int) bool {
+		return loadable[i].Meta().MinTime < loadable[j].Meta().MinTime
+	})
+
+	blockMetas := make([]BlockMeta, 0, len(loadable))
+	for _, b := range loadable {
+		blockMetas = append(blockMetas, b.Meta())
+	}
+	if overlaps := OverlappingBlocks(blockMetas); len(overlaps) > 0 {
+		level.Warn(db.logger).Log("msg", "overlapping blocks found during opening", "detail", overlaps.String())
+	}
+
+	// Close all previously open readers and add the new ones to the cache.
+	for _, closer := range db.closers {
+		closer.Close()
+	}
+
+	blockClosers := make([]io.Closer, len(loadable))
+	blockReaders := make([]BlockReader, len(loadable))
+	for i, b := range loadable {
+		blockClosers[i] = b
+		blockReaders[i] = b
+	}
+	db.closers = blockClosers
+
+	return blockReaders, nil
+}
+
+// Close all block readers.
+func (db *DBReadOnly) Close() error {
+	select {
+	case <-db.closed:
+		return ErrClosed
+	default:
+	}
+	close(db.closed)
+
+	var merr tsdb_errors.MultiError
+
+	for _, b := range db.closers {
+		merr.Add(b.Close())
+	}
+	return merr.Err()
+}
+
 // Open returns a new DB in the given directory.
 func Open(dir string, l log.Logger, r prometheus.Registerer, opts *Options) (db *DB, err error) {
 	if err := os.MkdirAll(dir, 0777); err != nil {
@@ -514,8 +686,10 @@ func (db *DB) compact() (err error) {
 	return nil
 }
 
-func (db *DB) getBlock(id ulid.ULID) (*Block, bool) {
+// getBlock iterates a given block range to find a block by a given id.
-	for _, b := range db.blocks {
+// If found it returns the block itself and a boolean to indicate that it was found.
+func getBlock(allBlocks []*Block, id ulid.ULID) (*Block, bool) {
+	for _, b := range allBlocks {
 		if b.Meta().ULID == id {
 			return b, true
 		}
@@ -533,14 +707,14 @@ func (db *DB) reload() (err error) {
 		db.metrics.reloads.Inc()
 	}()
 
-	loadable, corrupted, err := db.openBlocks()
+	loadable, corrupted, err := openBlocks(db.logger, db.dir, db.blocks, db.chunkPool)
 	if err != nil {
 		return err
 	}
 
 	deletable := db.deletableBlocks(loadable)
 
-	// Corrupted blocks that have been replaced by parents can be safely ignored and deleted.
+	// Corrupted blocks that have been superseded by a loadable block can be safely ignored.
 	// This makes it resilient against the process crashing towards the end of a compaction.
 	// Creation of a new block and deletion of its parents cannot happen atomically.
 	// By creating blocks with their parents, we can pick up the deletion where it left off during a crash.
@@ -553,7 +727,7 @@ func (db *DB) reload() (err error) {
 	if len(corrupted) > 0 {
 		// Close all new blocks to release the lock for windows.
 		for _, block := range loadable {
-			if _, loaded := db.getBlock(block.Meta().ULID); !loaded {
+			if _, open := getBlock(db.blocks, block.Meta().ULID); !open {
 				block.Close()
 			}
 		}
@@ -621,24 +795,24 @@ func (db *DB) reload() (err error) {
 	return errors.Wrap(db.head.Truncate(maxt), "head truncate failed")
 }
 
-func (db *DB) openBlocks() (blocks []*Block, corrupted map[ulid.ULID]error, err error) {
+func openBlocks(l log.Logger, dir string, loaded []*Block, chunkPool chunkenc.Pool) (blocks []*Block, corrupted map[ulid.ULID]error, err error) {
-	dirs, err := blockDirs(db.dir)
+	bDirs, err := blockDirs(dir)
 	if err != nil {
 		return nil, nil, errors.Wrap(err, "find blocks")
 	}
 
 	corrupted = make(map[ulid.ULID]error)
-	for _, dir := range dirs {
+	for _, bDir := range bDirs {
-		meta, _, err := readMetaFile(dir)
+		meta, _, err := readMetaFile(bDir)
 		if err != nil {
-			level.Error(db.logger).Log("msg", "not a block dir", "dir", dir)
+			level.Error(l).Log("msg", "not a block dir", "dir", bDir)
 			continue
 		}
 
 		// See if we already have the block in memory or open it otherwise.
-		block, ok := db.getBlock(meta.ULID)
+		block, open := getBlock(loaded, meta.ULID)
-		if !ok {
+		if !open {
-			block, err = OpenBlock(db.logger, dir, db.chunkPool)
+			block, err = OpenBlock(l, bDir, chunkPool)
 			if err != nil {
 				corrupted[meta.ULID] = err
 				continue

vendor/github.com/prometheus/tsdb/head.go

@@ -25,6 +25,7 @@ import (
 
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
+	"github.com/oklog/ulid"
 	"github.com/pkg/errors"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/tsdb/chunkenc"
@@ -64,6 +65,7 @@ type Head struct {
 	logger     log.Logger
 	appendPool sync.Pool
 	bytesPool  sync.Pool
+	numSeries  uint64
 
 	minTime, maxTime int64 // Current min and max of the samples included in the head.
 	minValidTime     int64 // Mint allowed to be added to the head. It shouldn't be lower than the maxt of the last persisted block.
@@ -84,7 +86,7 @@ type Head struct {
 
 type headMetrics struct {
 	activeAppenders         prometheus.Gauge
-	series                  prometheus.Gauge
+	series                  prometheus.GaugeFunc
 	seriesCreated           prometheus.Counter
 	seriesRemoved           prometheus.Counter
 	seriesNotFound          prometheus.Counter
@@ -112,9 +114,11 @@ func newHeadMetrics(h *Head, r prometheus.Registerer) *headMetrics {
 		Name: "prometheus_tsdb_head_active_appenders",
 		Help: "Number of currently active appender transactions",
 	})
-	m.series = prometheus.NewGauge(prometheus.GaugeOpts{
+	m.series = prometheus.NewGaugeFunc(prometheus.GaugeOpts{
 		Name: "prometheus_tsdb_head_series",
 		Help: "Total number of series in the head block.",
+	}, func() float64 {
+		return float64(h.NumSeries())
 	})
 	m.seriesCreated = prometheus.NewCounter(prometheus.CounterOpts{
 		Name: "prometheus_tsdb_head_series_created_total",
@@ -502,6 +506,7 @@ func (h *Head) Init(minValidTime int64) error {
 		return nil
 	}
 
+	level.Info(h.logger).Log("msg", "replaying WAL, this may take awhile")
 	// Backfill the checkpoint first if it exists.
 	dir, startFrom, err := LastCheckpoint(h.wal.Dir())
 	if err != nil && err != ErrNotFound {
@@ -525,6 +530,7 @@ func (h *Head) Init(minValidTime int64) error {
 			return errors.Wrap(err, "backfill checkpoint")
 		}
 		startFrom++
+		level.Info(h.logger).Log("msg", "WAL checkpoint loaded")
 	}
 
 	// Find the last segment.
@@ -548,6 +554,7 @@ func (h *Head) Init(minValidTime int64) error {
 		if err != nil {
 			return err
 		}
+		level.Info(h.logger).Log("msg", "WAL segment loaded", "segment", i, "maxSegment", last)
 	}
 
 	return nil
@@ -698,6 +705,21 @@ func (h *rangeHead) MaxTime() int64 {
 	return h.maxt
 }
 
+func (h *rangeHead) NumSeries() uint64 {
+	return h.head.NumSeries()
+}
+
+func (h *rangeHead) Meta() BlockMeta {
+	return BlockMeta{
+		MinTime: h.MinTime(),
+		MaxTime: h.MaxTime(),
+		ULID:    h.head.Meta().ULID,
+		Stats: BlockStats{
+			NumSeries: h.NumSeries(),
+		},
+	}
+}
+
 // initAppender is a helper to initialize the time bounds of the head
 // upon the first sample it receives.
 type initAppender struct {
@@ -1022,9 +1044,11 @@ func (h *Head) gc() {
 	seriesRemoved := len(deleted)
 
 	h.metrics.seriesRemoved.Add(float64(seriesRemoved))
-	h.metrics.series.Sub(float64(seriesRemoved))
 	h.metrics.chunksRemoved.Add(float64(chunksRemoved))
 	h.metrics.chunks.Sub(float64(chunksRemoved))
+	// Using AddUint64 to substract series removed.
+	// See: https://golang.org/pkg/sync/atomic/#AddUint64.
+	atomic.AddUint64(&h.numSeries, ^uint64(seriesRemoved-1))
 
 	// Remove deleted series IDs from the postings lists.
 	h.postings.Delete(deleted)
@@ -1101,6 +1125,26 @@ func (h *Head) chunksRange(mint, maxt int64) *headChunkReader {
 	return &headChunkReader{head: h, mint: mint, maxt: maxt}
 }
 
+// NumSeries returns the number of active series in the head.
+func (h *Head) NumSeries() uint64 {
+	return atomic.LoadUint64(&h.numSeries)
+}
+
+// Meta returns meta information about the head.
+// The head is dynamic so will return dynamic results.
+func (h *Head) Meta() BlockMeta {
+	var id [16]byte
+	copy(id[:], "______head______")
+	return BlockMeta{
+		MinTime: h.MinTime(),
+		MaxTime: h.MaxTime(),
+		ULID:    ulid.ULID(id),
+		Stats: BlockStats{
+			NumSeries: h.NumSeries(),
+		},
+	}
+}
+
 // MinTime returns the lowest time bound on visible data in the head.
 func (h *Head) MinTime() int64 {
 	return atomic.LoadInt64(&h.minTime)
@@ -1185,9 +1229,9 @@ type safeChunk struct {
 	cid int
 }
 
-func (c *safeChunk) Iterator() chunkenc.Iterator {
+func (c *safeChunk) Iterator(reuseIter chunkenc.Iterator) chunkenc.Iterator {
 	c.s.Lock()
-	it := c.s.iterator(c.cid)
+	it := c.s.iterator(c.cid, reuseIter)
 	c.s.Unlock()
 	return it
 }
@@ -1347,8 +1391,8 @@ func (h *Head) getOrCreateWithID(id, hash uint64, lset labels.Labels) (*memSerie
 		return s, false
 	}
 
-	h.metrics.series.Inc()
 	h.metrics.seriesCreated.Inc()
+	atomic.AddUint64(&h.numSeries, 1)
 
 	h.postings.Add(id, lset)
 
@@ -1739,7 +1783,7 @@ func computeChunkEndTime(start, cur, max int64) int64 {
 	return start + (max-start)/a
 }
 
-func (s *memSeries) iterator(id int) chunkenc.Iterator {
+func (s *memSeries) iterator(id int, it chunkenc.Iterator) chunkenc.Iterator {
 	c := s.chunk(id)
 	// TODO(fabxc): Work around! A querier may have retrieved a pointer to a series' chunk,
 	// which got then garbage collected before it got accessed.
@@ -1749,17 +1793,23 @@ func (s *memSeries) iterator(id int) chunkenc.Iterator {
 	}
 
 	if id-s.firstChunkID < len(s.chunks)-1 {
-		return c.chunk.Iterator()
+		return c.chunk.Iterator(it)
 	}
 	// Serve the last 4 samples for the last chunk from the sample buffer
 	// as their compressed bytes may be mutated by added samples.
-	it := &memSafeIterator{
+	if msIter, ok := it.(*memSafeIterator); ok {
-		Iterator: c.chunk.Iterator(),
+		msIter.Iterator = c.chunk.Iterator(msIter.Iterator)
+		msIter.i = -1
+		msIter.total = c.chunk.NumSamples()
+		msIter.buf = s.sampleBuf
+		return msIter
+	}
+	return &memSafeIterator{
+		Iterator: c.chunk.Iterator(it),
 		i:        -1,
 		total:    c.chunk.NumSamples(),
 		buf:      s.sampleBuf,
 	}
-	return it
 }
 
 func (s *memSeries) head() *memChunk {

vendor/github.com/prometheus/tsdb/index/index.go

@@ -123,10 +123,10 @@ type Writer struct {
 	buf2    encoding.Encbuf
 	uint32s []uint32
 
-	symbols       map[string]uint32 // symbol offsets
+	symbols       map[string]uint32     // symbol offsets
-	seriesOffsets map[uint64]uint64 // offsets of series
+	seriesOffsets map[uint64]uint64     // offsets of series
-	labelIndexes  []hashEntry       // label index offsets
+	labelIndexes  []labelIndexHashEntry // label index offsets
-	postings      []hashEntry       // postings lists offsets
+	postings      []postingsHashEntry   // postings lists offsets
 
 	// Hold last series to validate that clients insert new series in order.
 	lastSeries labels.Labels
@@ -271,11 +271,11 @@ func (w *Writer) ensureStage(s indexWriterStage) error {
 
 	case idxStageDone:
 		w.toc.LabelIndicesTable = w.pos
-		if err := w.writeOffsetTable(w.labelIndexes); err != nil {
+		if err := w.writeLabelIndexesOffsetTable(); err != nil {
 			return err
 		}
 		w.toc.PostingsTable = w.pos
-		if err := w.writeOffsetTable(w.postings); err != nil {
+		if err := w.writePostingsOffsetTable(); err != nil {
 			return err
 		}
 		if err := w.writeTOC(); err != nil {
@@ -420,7 +420,7 @@ func (w *Writer) WriteLabelIndex(names []string, values []string) error {
 		return err
 	}
 
-	w.labelIndexes = append(w.labelIndexes, hashEntry{
+	w.labelIndexes = append(w.labelIndexes, labelIndexHashEntry{
 		keys:   names,
 		offset: w.pos,
 	})
@@ -447,12 +447,12 @@ func (w *Writer) WriteLabelIndex(names []string, values []string) error {
 	return errors.Wrap(err, "write label index")
 }
 
-// writeOffsetTable writes a sequence of readable hash entries.
+// writeLabelIndexesOffsetTable writes the label indices offset table.
-func (w *Writer) writeOffsetTable(entries []hashEntry) error {
+func (w *Writer) writeLabelIndexesOffsetTable() error {
 	w.buf2.Reset()
-	w.buf2.PutBE32int(len(entries))
+	w.buf2.PutBE32int(len(w.labelIndexes))
 
-	for _, e := range entries {
+	for _, e := range w.labelIndexes {
 		w.buf2.PutUvarint(len(e.keys))
 		for _, k := range e.keys {
 			w.buf2.PutUvarintStr(k)
@@ -467,6 +467,25 @@ func (w *Writer) writeOffsetTable(entries []hashEntry) error {
 	return w.write(w.buf1.Get(), w.buf2.Get())
 }
 
+// writePostingsOffsetTable writes the postings offset table.
+func (w *Writer) writePostingsOffsetTable() error {
+	w.buf2.Reset()
+	w.buf2.PutBE32int(len(w.postings))
+
+	for _, e := range w.postings {
+		w.buf2.PutUvarint(2)
+		w.buf2.PutUvarintStr(e.name)
+		w.buf2.PutUvarintStr(e.value)
+		w.buf2.PutUvarint64(e.offset)
+	}
+
+	w.buf1.Reset()
+	w.buf1.PutBE32int(w.buf2.Len())
+	w.buf2.PutHash(w.crc32)
+
+	return w.write(w.buf1.Get(), w.buf2.Get())
+}
+
 const indexTOCLen = 6*8 + 4
 
 func (w *Writer) writeTOC() error {
@@ -494,8 +513,9 @@ func (w *Writer) WritePostings(name, value string, it Postings) error {
 		return err
 	}
 
-	w.postings = append(w.postings, hashEntry{
+	w.postings = append(w.postings, postingsHashEntry{
-		keys:   []string{name, value},
+		name:   name,
+		value:  value,
 		offset: w.pos,
 	})
 
@@ -542,11 +562,16 @@ func (s uint32slice) Len() int           { return len(s) }
 func (s uint32slice) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
 func (s uint32slice) Less(i, j int) bool { return s[i] < s[j] }
 
-type hashEntry struct {
+type labelIndexHashEntry struct {
 	keys   []string
 	offset uint64
 }
 
+type postingsHashEntry struct {
+	name, value string
+	offset      uint64
+}
+
 func (w *Writer) Close() error {
 	if err := w.ensureStage(idxStageDone); err != nil {
 		return err
@@ -781,9 +806,13 @@ func ReadOffsetTable(bs ByteSlice, off uint64, f func([]string, uint64) error) e
 	d := encoding.NewDecbufAt(bs, int(off), castagnoliTable)
 	cnt := d.Be32()
 
+	// The Postings offset table takes only 2 keys per entry (name and value of label),
+	// and the LabelIndices offset table takes only 1 key per entry (a label name).
+	// Hence setting the size to max of both, i.e. 2.
+	keys := make([]string, 0, 2)
 	for d.Err() == nil && d.Len() > 0 && cnt > 0 {
 		keyCount := d.Uvarint()
-		keys := make([]string, 0, keyCount)
+		keys = keys[:0]
 
 		for i := 0; i < keyCount; i++ {
 			keys = append(keys, d.UvarintStr())
@@ -951,25 +980,30 @@ func (r *Reader) LabelNames() ([]string, error) {
 type stringTuples struct {
 	length  int      // tuple length
 	entries []string // flattened tuple entries
+	swapBuf []string
 }
 
 func NewStringTuples(entries []string, length int) (*stringTuples, error) {
 	if len(entries)%length != 0 {
 		return nil, errors.Wrap(encoding.ErrInvalidSize, "string tuple list")
 	}
-	return &stringTuples{entries: entries, length: length}, nil
+	return &stringTuples{
+		entries: entries,
+		length:  length,
+	}, nil
 }
 
 func (t *stringTuples) Len() int                   { return len(t.entries) / t.length }
 func (t *stringTuples) At(i int) ([]string, error) { return t.entries[i : i+t.length], nil }
 
 func (t *stringTuples) Swap(i, j int) {
-	c := make([]string, t.length)
+	if t.swapBuf == nil {
-	copy(c, t.entries[i:i+t.length])
+		t.swapBuf = make([]string, t.length)
-
+	}
+	copy(t.swapBuf, t.entries[i:i+t.length])
 	for k := 0; k < t.length; k++ {
 		t.entries[i+k] = t.entries[j+k]
-		t.entries[j+k] = c[k]
+		t.entries[j+k] = t.swapBuf[k]
 	}
 }
 

vendor/github.com/prometheus/tsdb/querier.go

@@ -1060,8 +1060,9 @@ func (it *verticalMergeSeriesIterator) Err() error {
 type chunkSeriesIterator struct {
 	chunks []chunks.Meta
 
-	i   int
+	i          int
-	cur chunkenc.Iterator
+	cur        chunkenc.Iterator
+	bufDelIter *deletedIterator
 
 	maxt, mint int64
 
@@ -1069,21 +1070,32 @@ type chunkSeriesIterator struct {
 }
 
 func newChunkSeriesIterator(cs []chunks.Meta, dranges Intervals, mint, maxt int64) *chunkSeriesIterator {
-	it := cs[0].Chunk.Iterator()
+	csi := &chunkSeriesIterator{
-
-	if len(dranges) > 0 {
-		it = &deletedIterator{it: it, intervals: dranges}
-	}
-	return &chunkSeriesIterator{
 		chunks: cs,
 		i:      0,
-		cur:    it,
 
 		mint: mint,
 		maxt: maxt,
 
 		intervals: dranges,
 	}
+	csi.resetCurIterator()
+
+	return csi
+}
+
+func (it *chunkSeriesIterator) resetCurIterator() {
+	if len(it.intervals) == 0 {
+		it.cur = it.chunks[it.i].Chunk.Iterator(it.cur)
+		return
+	}
+	if it.bufDelIter == nil {
+		it.bufDelIter = &deletedIterator{
+			intervals: it.intervals,
+		}
+	}
+	it.bufDelIter.it = it.chunks[it.i].Chunk.Iterator(it.bufDelIter.it)
+	it.cur = it.bufDelIter
 }
 
 func (it *chunkSeriesIterator) Seek(t int64) (ok bool) {
@@ -1102,10 +1114,7 @@ func (it *chunkSeriesIterator) Seek(t int64) (ok bool) {
 		}
 	}
 
-	it.cur = it.chunks[it.i].Chunk.Iterator()
+	it.resetCurIterator()
-	if len(it.intervals) > 0 {
-		it.cur = &deletedIterator{it: it.cur, intervals: it.intervals}
-	}
 
 	for it.cur.Next() {
 		t0, _ := it.cur.At()
@@ -1145,10 +1154,7 @@ func (it *chunkSeriesIterator) Next() bool {
 	}
 
 	it.i++
-	it.cur = it.chunks[it.i].Chunk.Iterator()
+	it.resetCurIterator()
-	if len(it.intervals) > 0 {
-		it.cur = &deletedIterator{it: it.cur, intervals: it.intervals}
-	}
 
 	return it.Next()
 }

vendor/github.com/prometheus/tsdb/wal/wal.go

@@ -203,6 +203,48 @@ func NewSize(logger log.Logger, reg prometheus.Registerer, dir string, segmentSi
 		stopc:       make(chan chan struct{}),
 		compress:    compress,
 	}
+	registerMetrics(reg, w)
+
+	_, j, err := w.Segments()
+	// Index of the Segment we want to open and write to.
+	writeSegmentIndex := 0
+	if err != nil {
+		return nil, errors.Wrap(err, "get segment range")
+	}
+	// If some segments already exist create one with a higher index than the last segment.
+	if j != -1 {
+		writeSegmentIndex = j + 1
+	}
+
+	segment, err := CreateSegment(w.dir, writeSegmentIndex)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := w.setSegment(segment); err != nil {
+		return nil, err
+	}
+
+	go w.run()
+
+	return w, nil
+}
+
+// Open an existing WAL.
+func Open(logger log.Logger, reg prometheus.Registerer, dir string) (*WAL, error) {
+	if logger == nil {
+		logger = log.NewNopLogger()
+	}
+	w := &WAL{
+		dir:    dir,
+		logger: logger,
+	}
+
+	registerMetrics(reg, w)
+	return w, nil
+}
+
+func registerMetrics(reg prometheus.Registerer, w *WAL) {
 	w.fsyncDuration = prometheus.NewSummary(prometheus.SummaryOpts{
 		Name:       "prometheus_tsdb_wal_fsync_duration_seconds",
 		Help:       "Duration of WAL fsync.",
@@ -231,30 +273,6 @@ func NewSize(logger log.Logger, reg prometheus.Registerer, dir string, segmentSi
 	if reg != nil {
 		reg.MustRegister(w.fsyncDuration, w.pageFlushes, w.pageCompletions, w.truncateFail, w.truncateTotal, w.currentSegment)
 	}
-
-	_, j, err := w.Segments()
-	// Index of the Segment we want to open and write to.
-	writeSegmentIndex := 0
-	if err != nil {
-		return nil, errors.Wrap(err, "get segment range")
-	}
-	// If some segments already exist create one with a higher index than the last segment.
-	if j != -1 {
-		writeSegmentIndex = j + 1
-	}
-
-	segment, err := CreateSegment(w.dir, writeSegmentIndex)
-	if err != nil {
-		return nil, err
-	}
-
-	if err := w.setSegment(segment); err != nil {
-		return nil, err
-	}
-
-	go w.run()
-
-	return w, nil
 }
 
 // CompressionEnabled returns if compression is enabled on this WAL.
@@ -302,7 +320,6 @@ func (w *WAL) Repair(origErr error) error {
 	if cerr.Segment < 0 {
 		return errors.New("corruption error does not specify position")
 	}
-
 	level.Warn(w.logger).Log("msg", "starting corruption repair",
 		"segment", cerr.Segment, "offset", cerr.Offset)
 
@@ -487,7 +504,6 @@ func (w *WAL) flushPage(clear bool) error {
 
 // First Byte of header format:
 // [ 4 bits unallocated] [1 bit snappy compression flag] [ 3 bit record type ]
-
 const (
 	snappyMask  = 1 << 3
 	recTypeMask = snappyMask - 1

vendor/modules.txt

@@ -277,7 +277,7 @@ github.com/prometheus/common/internal/bitbucket.org/ww/goautoneg
 # github.com/prometheus/procfs v0.0.2
 github.com/prometheus/procfs
 github.com/prometheus/procfs/internal/fs
-# github.com/prometheus/tsdb v0.9.1
+# github.com/prometheus/tsdb v0.10.0
 github.com/prometheus/tsdb
 github.com/prometheus/tsdb/fileutil
 github.com/prometheus/tsdb/labels