vendor: sync organisation migration of tsdb

storage/tsdb/tsdb.go

@@ -4,11 +4,11 @@ import (
 	"time"
 	"unsafe"
 
-	"github.com/fabxc/tsdb"
-	tsdbLabels "github.com/fabxc/tsdb/labels"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/prometheus/pkg/labels"
 	"github.com/prometheus/prometheus/storage"
+	"github.com/prometheus/tsdb"
+	tsdbLabels "github.com/prometheus/tsdb/labels"
 )
 
 // adapter implements a storage.Storage around TSDB.

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

@@ -10,8 +10,8 @@ import (
 	"os"
 
 	"github.com/coreos/etcd/pkg/fileutil"
-	"github.com/fabxc/tsdb/chunks"
 	"github.com/pkg/errors"
+	"github.com/prometheus/tsdb/chunks"
 )
 
 const (

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

@@ -0,0 +1,169 @@
+package chunks
+
+import "io"
+
+// bstream is a stream of bits
+type bstream struct {
+	stream []byte // the data stream
+	count  uint8  // how many bits are valid in current byte
+}
+
+func newBReader(b []byte) *bstream {
+	return &bstream{stream: b, count: 8}
+}
+
+func newBWriter(size int) *bstream {
+	return &bstream{stream: make([]byte, 0, size), count: 0}
+}
+
+func (b *bstream) clone() *bstream {
+	d := make([]byte, len(b.stream))
+	copy(d, b.stream)
+	return &bstream{stream: d, count: b.count}
+}
+
+func (b *bstream) bytes() []byte {
+	return b.stream
+}
+
+type bit bool
+
+const (
+	zero bit = false
+	one  bit = true
+)
+
+func (b *bstream) writeBit(bit bit) {
+	if b.count == 0 {
+		b.stream = append(b.stream, 0)
+		b.count = 8
+	}
+
+	i := len(b.stream) - 1
+
+	if bit {
+		b.stream[i] |= 1 << (b.count - 1)
+	}
+
+	b.count--
+}
+
+func (b *bstream) writeByte(byt byte) {
+	if b.count == 0 {
+		b.stream = append(b.stream, 0)
+		b.count = 8
+	}
+
+	i := len(b.stream) - 1
+
+	// fill up b.b with b.count bits from byt
+	b.stream[i] |= byt >> (8 - b.count)
+
+	b.stream = append(b.stream, 0)
+	i++
+	b.stream[i] = byt << b.count
+}
+
+func (b *bstream) writeBits(u uint64, nbits int) {
+	u <<= (64 - uint(nbits))
+	for nbits >= 8 {
+		byt := byte(u >> 56)
+		b.writeByte(byt)
+		u <<= 8
+		nbits -= 8
+	}
+
+	for nbits > 0 {
+		b.writeBit((u >> 63) == 1)
+		u <<= 1
+		nbits--
+	}
+}
+
+func (b *bstream) readBit() (bit, error) {
+	if len(b.stream) == 0 {
+		return false, io.EOF
+	}
+
+	if b.count == 0 {
+		b.stream = b.stream[1:]
+
+		if len(b.stream) == 0 {
+			return false, io.EOF
+		}
+		b.count = 8
+	}
+
+	d := (b.stream[0] << (8 - b.count)) & 0x80
+	b.count--
+	return d != 0, nil
+}
+
+func (b *bstream) ReadByte() (byte, error) {
+	return b.readByte()
+}
+
+func (b *bstream) readByte() (byte, error) {
+	if len(b.stream) == 0 {
+		return 0, io.EOF
+	}
+
+	if b.count == 0 {
+		b.stream = b.stream[1:]
+
+		if len(b.stream) == 0 {
+			return 0, io.EOF
+		}
+		return b.stream[0], nil
+	}
+
+	if b.count == 8 {
+		b.count = 0
+		return b.stream[0], nil
+	}
+
+	byt := b.stream[0] << (8 - b.count)
+	b.stream = b.stream[1:]
+
+	if len(b.stream) == 0 {
+		return 0, io.EOF
+	}
+
+	// We just advanced the stream and can assume the shift to be 0.
+	byt |= b.stream[0] >> b.count
+
+	return byt, nil
+}
+
+func (b *bstream) readBits(nbits int) (uint64, error) {
+	var u uint64
+
+	for nbits >= 8 {
+		byt, err := b.readByte()
+		if err != nil {
+			return 0, err
+		}
+
+		u = (u << 8) | uint64(byt)
+		nbits -= 8
+	}
+
+	if nbits == 0 {
+		return u, nil
+	}
+
+	if nbits > int(b.count) {
+		u = (u << uint(b.count)) | uint64((b.stream[0]<<(8-b.count))>>(8-b.count))
+		nbits -= int(b.count)
+		b.stream = b.stream[1:]
+
+		if len(b.stream) == 0 {
+			return 0, io.EOF
+		}
+		b.count = 8
+	}
+
+	u = (u << uint(nbits)) | uint64((b.stream[0]<<(8-b.count))>>(8-uint(nbits)))
+	b.count -= uint8(nbits)
+	return u, nil
+}

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

@@ -0,0 +1,57 @@
+package chunks
+
+import (
+	"encoding/binary"
+	"fmt"
+)
+
+// Encoding is the identifier for a chunk encoding
+type Encoding uint8
+
+func (e Encoding) String() string {
+	switch e {
+	case EncNone:
+		return "none"
+	case EncXOR:
+		return "XOR"
+	}
+	return "<unknown>"
+}
+
+// The different available chunk encodings.
+const (
+	EncNone Encoding = iota
+	EncXOR
+)
+
+// Chunk holds a sequence of sample pairs that can be iterated over and appended to.
+type Chunk interface {
+	Bytes() []byte
+	Encoding() Encoding
+	Appender() (Appender, error)
+	Iterator() Iterator
+}
+
+// FromData returns a chunk from a byte slice of chunk data.
+func FromData(e Encoding, d []byte) (Chunk, error) {
+	switch e {
+	case EncXOR:
+		return &XORChunk{
+			b:   &bstream{count: 0, stream: d},
+			num: binary.BigEndian.Uint16(d),
+		}, nil
+	}
+	return nil, fmt.Errorf("unknown chunk encoding: %d", e)
+}
+
+// Appender adds sample pairs to a chunk.
+type Appender interface {
+	Append(int64, float64)
+}
+
+// Iterator is a simple iterator that can only get the next value.
+type Iterator interface {
+	At() (int64, float64)
+	Err() error
+	Next() bool
+}

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

@@ -0,0 +1,342 @@
+package chunks
+
+import (
+	"encoding/binary"
+	"math"
+
+	bits "github.com/dgryski/go-bits"
+)
+
+// XORChunk holds XOR encoded sample data.
+type XORChunk struct {
+	b   *bstream
+	num uint16
+}
+
+// NewXORChunk returns a new chunk with XOR encoding of the given size.
+func NewXORChunk() *XORChunk {
+	b := make([]byte, 2, 128)
+	return &XORChunk{b: &bstream{stream: b, count: 0}}
+}
+
+// Encoding returns the encoding type.
+func (c *XORChunk) Encoding() Encoding {
+	return EncXOR
+}
+
+// Bytes returns the underlying byte slice of the chunk.
+func (c *XORChunk) Bytes() []byte {
+	return c.b.bytes()
+}
+
+// Appender implements the Chunk interface.
+func (c *XORChunk) Appender() (Appender, error) {
+	it := c.iterator()
+
+	// To get an appender we must know the state it would have if we had
+	// appended all existing data from scratch.
+	// We iterate through the end and populate via the iterator's state.
+	for it.Next() {
+	}
+	if err := it.Err(); err != nil {
+		return nil, err
+	}
+
+	a := &xorAppender{
+		c:        c,
+		b:        c.b,
+		t:        it.t,
+		v:        it.val,
+		tDelta:   it.tDelta,
+		leading:  it.leading,
+		trailing: it.trailing,
+	}
+	if binary.BigEndian.Uint16(a.b.bytes()) == 0 {
+		a.leading = 0xff
+	}
+	return a, nil
+}
+
+func (c *XORChunk) 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.
+	return &xorIterator{
+		br:       newBReader(c.b.bytes()[2:]),
+		numTotal: binary.BigEndian.Uint16(c.b.bytes()),
+	}
+}
+
+// Iterator implements the Chunk interface.
+func (c *XORChunk) Iterator() Iterator {
+	return c.iterator()
+}
+
+type xorAppender struct {
+	c *XORChunk
+	b *bstream
+
+	t      int64
+	v      float64
+	tDelta uint64
+
+	leading  uint8
+	trailing uint8
+}
+
+func (a *xorAppender) Append(t int64, v float64) {
+	var tDelta uint64
+	num := binary.BigEndian.Uint16(a.b.bytes())
+
+	if num == 0 {
+		buf := make([]byte, binary.MaxVarintLen64)
+		for _, b := range buf[:binary.PutVarint(buf, t)] {
+			a.b.writeByte(b)
+		}
+		a.b.writeBits(math.Float64bits(v), 64)
+
+	} else if num == 1 {
+		tDelta = uint64(t - a.t)
+
+		buf := make([]byte, binary.MaxVarintLen64)
+		for _, b := range buf[:binary.PutUvarint(buf, tDelta)] {
+			a.b.writeByte(b)
+		}
+
+		a.writeVDelta(v)
+
+	} else {
+		tDelta = uint64(t - a.t)
+		dod := int64(tDelta - a.tDelta)
+
+		// Gorilla has a max resolution of seconds, Prometheus milliseconds.
+		// Thus we use higher value range steps with larger bit size.
+		switch {
+		case dod == 0:
+			a.b.writeBit(zero)
+		case bitRange(dod, 14):
+			a.b.writeBits(0x02, 2) // '10'
+			a.b.writeBits(uint64(dod), 14)
+		case bitRange(dod, 17):
+			a.b.writeBits(0x06, 3) // '110'
+			a.b.writeBits(uint64(dod), 17)
+		case bitRange(dod, 20):
+			a.b.writeBits(0x0e, 4) // '1110'
+			a.b.writeBits(uint64(dod), 20)
+		default:
+			a.b.writeBits(0x0f, 4) // '1111'
+			a.b.writeBits(uint64(dod), 64)
+		}
+
+		a.writeVDelta(v)
+	}
+
+	a.t = t
+	a.v = v
+	binary.BigEndian.PutUint16(a.b.bytes(), num+1)
+	a.tDelta = tDelta
+}
+
+func bitRange(x int64, nbits uint8) bool {
+	return -((1<<(nbits-1))-1) <= x && x <= 1<<(nbits-1)
+}
+
+func (a *xorAppender) writeVDelta(v float64) {
+	vDelta := math.Float64bits(v) ^ math.Float64bits(a.v)
+
+	if vDelta == 0 {
+		a.b.writeBit(zero)
+		return
+	}
+	a.b.writeBit(one)
+
+	leading := uint8(bits.Clz(vDelta))
+	trailing := uint8(bits.Ctz(vDelta))
+
+	// Clamp number of leading zeros to avoid overflow when encoding.
+	if leading >= 32 {
+		leading = 31
+	}
+
+	if a.leading != 0xff && leading >= a.leading && trailing >= a.trailing {
+		a.b.writeBit(zero)
+		a.b.writeBits(vDelta>>a.trailing, 64-int(a.leading)-int(a.trailing))
+	} else {
+		a.leading, a.trailing = leading, trailing
+
+		a.b.writeBit(one)
+		a.b.writeBits(uint64(leading), 5)
+
+		// Note that if leading == trailing == 0, then sigbits == 64.  But that value doesn't actually fit into the 6 bits we have.
+		// Luckily, we never need to encode 0 significant bits, since that would put us in the other case (vdelta == 0).
+		// So instead we write out a 0 and adjust it back to 64 on unpacking.
+		sigbits := 64 - leading - trailing
+		a.b.writeBits(uint64(sigbits), 6)
+		a.b.writeBits(vDelta>>trailing, int(sigbits))
+	}
+}
+
+type xorIterator struct {
+	br       *bstream
+	numTotal uint16
+	numRead  uint16
+
+	t   int64
+	val float64
+
+	leading  uint8
+	trailing uint8
+
+	tDelta uint64
+	err    error
+}
+
+func (it *xorIterator) At() (int64, float64) {
+	return it.t, it.val
+}
+
+func (it *xorIterator) Err() error {
+	return it.err
+}
+
+func (it *xorIterator) Next() bool {
+	if it.err != nil || it.numRead == it.numTotal {
+		return false
+	}
+
+	if it.numRead == 0 {
+		t, err := binary.ReadVarint(it.br)
+		if err != nil {
+			it.err = err
+			return false
+		}
+		v, err := it.br.readBits(64)
+		if err != nil {
+			it.err = err
+			return false
+		}
+		it.t = int64(t)
+		it.val = math.Float64frombits(v)
+
+		it.numRead++
+		return true
+	}
+	if it.numRead == 1 {
+		tDelta, err := binary.ReadUvarint(it.br)
+		if err != nil {
+			it.err = err
+			return false
+		}
+		it.tDelta = tDelta
+		it.t = it.t + int64(it.tDelta)
+
+		return it.readValue()
+	}
+
+	var d byte
+	// read delta-of-delta
+	for i := 0; i < 4; i++ {
+		d <<= 1
+		bit, err := it.br.readBit()
+		if err != nil {
+			it.err = err
+			return false
+		}
+		if bit == zero {
+			break
+		}
+		d |= 1
+	}
+	var sz uint8
+	var dod int64
+	switch d {
+	case 0x00:
+		// dod == 0
+	case 0x02:
+		sz = 14
+	case 0x06:
+		sz = 17
+	case 0x0e:
+		sz = 20
+	case 0x0f:
+		bits, err := it.br.readBits(64)
+		if err != nil {
+			it.err = err
+			return false
+		}
+
+		dod = int64(bits)
+	}
+
+	if sz != 0 {
+		bits, err := it.br.readBits(int(sz))
+		if err != nil {
+			it.err = err
+			return false
+		}
+		if bits > (1 << (sz - 1)) {
+			// or something
+			bits = bits - (1 << sz)
+		}
+		dod = int64(bits)
+	}
+
+	it.tDelta = uint64(int64(it.tDelta) + dod)
+	it.t = it.t + int64(it.tDelta)
+
+	return it.readValue()
+}
+
+func (it *xorIterator) readValue() bool {
+	bit, err := it.br.readBit()
+	if err != nil {
+		it.err = err
+		return false
+	}
+
+	if bit == zero {
+		// it.val = it.val
+	} else {
+		bit, err := it.br.readBit()
+		if err != nil {
+			it.err = err
+			return false
+		}
+		if bit == zero {
+			// reuse leading/trailing zero bits
+			// it.leading, it.trailing = it.leading, it.trailing
+		} else {
+			bits, err := it.br.readBits(5)
+			if err != nil {
+				it.err = err
+				return false
+			}
+			it.leading = uint8(bits)
+
+			bits, err = it.br.readBits(6)
+			if err != nil {
+				it.err = err
+				return false
+			}
+			mbits := uint8(bits)
+			// 0 significant bits here means we overflowed and we actually need 64; see comment in encoder
+			if mbits == 0 {
+				mbits = 64
+			}
+			it.trailing = 64 - it.leading - mbits
+		}
+
+		mbits := int(64 - it.leading - it.trailing)
+		bits, err := it.br.readBits(mbits)
+		if err != nil {
+			it.err = err
+			return false
+		}
+		vbits := math.Float64bits(it.val)
+		vbits ^= (bits << it.trailing)
+		it.val = math.Float64frombits(vbits)
+	}
+
+	it.numRead++
+	return true
+}

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

@@ -8,11 +8,11 @@ import (
 	"time"
 
 	"github.com/coreos/etcd/pkg/fileutil"
-	"github.com/fabxc/tsdb/labels"
 	"github.com/go-kit/kit/log"
 	"github.com/oklog/ulid"
 	"github.com/pkg/errors"
 	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/tsdb/labels"
 )
 
 // Compactor provides compaction against an underlying storage

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

@@ -18,11 +18,11 @@ import (
 	"golang.org/x/sync/errgroup"
 
 	"github.com/coreos/etcd/pkg/fileutil"
-	"github.com/fabxc/tsdb/labels"
 	"github.com/go-kit/kit/log"
 	"github.com/nightlyone/lockfile"
 	"github.com/pkg/errors"
 	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/tsdb/labels"
 )
 
 // DefaultOptions used for the DB. They are sane for setups using
@@ -466,18 +466,19 @@ func (db *DB) Appender() Appender {
 	// anyway. For now this, with combination of only having a single timestamp per batch,
 	// prevents opening more than one appender and hitting an unresolved deadlock (#11).
 	//
-	// // Only instantiate appender after returning the headmtx to avoid
-	// // questionable locking order.
-	// db.headmtx.RLock()
-	// app := db.appendable()
-	// db.headmtx.RUnlock()
 
-	// for _, b := range app {
-	// 	a.heads = append(a.heads, &metaAppender{
-	// 		meta: b.Meta(),
-	// 		app:  b.Appender().(*headAppender),
-	// 	})
-	// }
+	// Only instantiate appender after returning the headmtx to avoid
+	// questionable locking order.
+	db.headmtx.RLock()
+	app := db.appendable()
+	db.headmtx.RUnlock()
+
+	for _, b := range app {
+		a.heads = append(a.heads, &metaAppender{
+			meta: b.Meta(),
+			app:  b.Appender(),
+		})
+	}
 
 	return a
 }
@@ -556,26 +557,26 @@ func (a *dbAppender) appenderFor(t int64) (*metaAppender, error) {
 		a.db.headmtx.Unlock()
 
 		// XXX(fabxc): temporary workaround. See comment on instantiating DB.Appender.
-		for _, b := range newHeads {
-			// Only get appender for the block with the specific timestamp.
-			if t >= b.Meta().MaxTime {
-				continue
-			}
-			a.heads = append(a.heads, &metaAppender{
-				app:  b.Appender(),
-				meta: b.Meta(),
-			})
-			break
-		}
-
-		// // Instantiate appenders after returning headmtx to avoid questionable
-		// // locking order.
 		// for _, b := range newHeads {
+		// 	// Only get appender for the block with the specific timestamp.
+		// 	if t >= b.Meta().MaxTime {
+		// 		continue
+		// 	}
 		// 	a.heads = append(a.heads, &metaAppender{
 		// 		app:  b.Appender(),
 		// 		meta: b.Meta(),
 		// 	})
+		// 	break
 		// }
+
+		// Instantiate appenders after returning headmtx to avoid questionable
+		// locking order.
+		for _, b := range newHeads {
+			a.heads = append(a.heads, &metaAppender{
+				app:  b.Appender(),
+				meta: b.Meta(),
+			})
+		}
 	}
 	for i := len(a.heads) - 1; i >= 0; i-- {
 		if h := a.heads[i]; t >= h.meta.MinTime {
@@ -613,28 +614,37 @@ func (db *DB) ensureHead(t int64) error {
 }
 
 func (a *dbAppender) Commit() error {
-	var merr MultiError
+	defer a.db.mtx.RUnlock()
+
+	// Commits to partial appenders must be concurrent as concurrent appenders
+	// may have conflicting locks on head appenders.
+	// XXX(fabxc): is this a leaky abstraction? Should make an effort to catch a multi-error?
+	var g errgroup.Group
 
 	for _, h := range a.heads {
-		merr.Add(h.app.Commit())
+		g.Go(h.app.Commit)
 	}
-	a.db.mtx.RUnlock()
 
-	if merr.Err() == nil {
-		a.db.metrics.samplesAppended.Add(float64(a.samples))
+	if err := g.Wait(); err != nil {
+		return err
 	}
-	return merr.Err()
+	// XXX(fabxc): Push the metric down into head block to account properly
+	// for partial appends?
+	a.db.metrics.samplesAppended.Add(float64(a.samples))
+
+	return nil
 }
 
 func (a *dbAppender) Rollback() error {
-	var merr MultiError
+	defer a.db.mtx.RUnlock()
+
+	var g errgroup.Group
 
 	for _, h := range a.heads {
-		merr.Add(h.app.Rollback())
+		g.Go(h.app.Commit)
 	}
-	a.db.mtx.RUnlock()
 
-	return merr.Err()
+	return g.Wait()
 }
 
 // appendable returns a copy of a slice of HeadBlocks that can still be appended to.

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

@@ -10,11 +10,11 @@ import (
 	"sync/atomic"
 	"time"
 
-	"github.com/fabxc/tsdb/chunks"
-	"github.com/fabxc/tsdb/labels"
 	"github.com/go-kit/kit/log"
 	"github.com/oklog/ulid"
 	"github.com/pkg/errors"
+	"github.com/prometheus/tsdb/chunks"
+	"github.com/prometheus/tsdb/labels"
 )
 
 var (

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

@@ -13,8 +13,8 @@ import (
 	"strings"
 
 	"github.com/coreos/etcd/pkg/fileutil"
-	"github.com/fabxc/tsdb/labels"
 	"github.com/pkg/errors"
+	"github.com/prometheus/tsdb/labels"
 )
 
 const (

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

@@ -0,0 +1,150 @@
+package labels
+
+import (
+	"bytes"
+	"sort"
+	"strconv"
+	"strings"
+
+	"github.com/cespare/xxhash"
+)
+
+const sep = '\xff'
+
+// Label is a key/value pair of strings.
+type Label struct {
+	Name, Value string
+}
+
+// Labels is a sorted set of labels. Order has to be guaranteed upon
+// instantiation.
+type Labels []Label
+
+func (ls Labels) Len() int           { return len(ls) }
+func (ls Labels) Swap(i, j int)      { ls[i], ls[j] = ls[j], ls[i] }
+func (ls Labels) Less(i, j int) bool { return ls[i].Name < ls[j].Name }
+
+func (ls Labels) String() string {
+	var b bytes.Buffer
+
+	b.WriteByte('{')
+	for i, l := range ls {
+		if i > 0 {
+			b.WriteByte(',')
+		}
+		b.WriteString(l.Name)
+		b.WriteByte('=')
+		b.WriteString(strconv.Quote(l.Value))
+	}
+	b.WriteByte('}')
+
+	return b.String()
+}
+
+// Hash returns a hash value for the label set.
+func (ls Labels) Hash() uint64 {
+	b := make([]byte, 0, 1024)
+
+	for _, v := range ls {
+		b = append(b, v.Name...)
+		b = append(b, sep)
+		b = append(b, v.Value...)
+		b = append(b, sep)
+	}
+	return xxhash.Sum64(b)
+}
+
+// Get returns the value for the label with the given name.
+// Returns an empty string if the label doesn't exist.
+func (ls Labels) Get(name string) string {
+	for _, l := range ls {
+		if l.Name == name {
+			return l.Value
+		}
+	}
+	return ""
+}
+
+// Equals returns whether the two label sets are equal.
+func (ls Labels) Equals(o Labels) bool {
+	if len(ls) != len(o) {
+		return false
+	}
+	for i, l := range ls {
+		if l.Name != o[i].Name || l.Value != o[i].Value {
+			return false
+		}
+	}
+	return true
+}
+
+// Map returns a string map of the labels.
+func (ls Labels) Map() map[string]string {
+	m := make(map[string]string, len(ls))
+	for _, l := range ls {
+		m[l.Name] = l.Value
+	}
+	return m
+}
+
+// New returns a sorted Labels from the given labels.
+// The caller has to guarantee that all label names are unique.
+func New(ls ...Label) Labels {
+	set := make(Labels, 0, len(ls))
+	for _, l := range ls {
+		set = append(set, l)
+	}
+	sort.Sort(set)
+
+	return set
+}
+
+// FromMap returns new sorted Labels from the given map.
+func FromMap(m map[string]string) Labels {
+	l := make([]Label, 0, len(m))
+	for k, v := range m {
+		l = append(l, Label{Name: k, Value: v})
+	}
+	return New(l...)
+}
+
+// FromStrings creates new labels from pairs of strings.
+func FromStrings(ss ...string) Labels {
+	if len(ss)%2 != 0 {
+		panic("invalid number of strings")
+	}
+	var res Labels
+	for i := 0; i < len(ss); i += 2 {
+		res = append(res, Label{Name: ss[i], Value: ss[i+1]})
+	}
+
+	sort.Sort(res)
+	return res
+}
+
+// Compare compares the two label sets.
+// The result will be 0 if a==b, <0 if a < b, and >0 if a > b.
+func Compare(a, b Labels) int {
+	l := len(a)
+	if len(b) < l {
+		l = len(b)
+	}
+
+	for i := 0; i < l; i++ {
+		if d := strings.Compare(a[i].Name, b[i].Name); d != 0 {
+			return d
+		}
+		if d := strings.Compare(a[i].Value, b[i].Value); d != 0 {
+			return d
+		}
+	}
+	// If all labels so far were in common, the set with fewer labels comes first.
+	return len(a) - len(b)
+}
+
+// Slice is a sortable slice of label sets.
+type Slice []Labels
+
+func (s Slice) Len() int           { return len(s) }
+func (s Slice) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
+func (s Slice) Less(i, j int) bool { return Compare(s[i], s[j]) < 0 }

vendor/github.com/prometheus/tsdb/labels/selector.go

@@ -0,0 +1,70 @@
+package labels
+
+import "regexp"
+
+// Selector holds constraints for matching against a label set.
+type Selector []Matcher
+
+// Matches returns whether the labels satisfy all matchers.
+func (s Selector) Matches(labels Labels) bool {
+	for _, m := range s {
+		if v := labels.Get(m.Name()); !m.Matches(v) {
+			return false
+		}
+	}
+	return true
+}
+
+// Matcher specifies a constraint for the value of a label.
+type Matcher interface {
+	// Name returns the label name the matcher should apply to.
+	Name() string
+	// Matches checks whether a value fulfills the constraints.
+	Matches(v string) bool
+}
+
+// EqualMatcher matches on equality.
+type EqualMatcher struct {
+	name, value string
+}
+
+// Name implements Matcher interface.
+func (m *EqualMatcher) Name() string { return m.name }
+
+// Matches implements Matcher interface.
+func (m *EqualMatcher) Matches(v string) bool { return v == m.value }
+
+// NewEqualMatcher returns a new matcher matching an exact label value.
+func NewEqualMatcher(name, value string) Matcher {
+	return &EqualMatcher{name: name, value: value}
+}
+
+type regexpMatcher struct {
+	name string
+	re   *regexp.Regexp
+}
+
+func (m *regexpMatcher) Name() string          { return m.name }
+func (m *regexpMatcher) Matches(v string) bool { return m.re.MatchString(v) }
+
+// NewRegexpMatcher returns a new matcher verifying that a value matches
+// the regular expression pattern.
+func NewRegexpMatcher(name, pattern string) (Matcher, error) {
+	re, err := regexp.Compile(pattern)
+	if err != nil {
+		return nil, err
+	}
+	return &regexpMatcher{name: name, re: re}, nil
+}
+
+// notMatcher inverts the matching result for a matcher.
+type notMatcher struct {
+	Matcher
+}
+
+func (m *notMatcher) Matches(v string) bool { return !m.Matcher.Matches(v) }
+
+// Not inverts the matcher's matching result.
+func Not(m Matcher) Matcher {
+	return &notMatcher{m}
+}

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

@@ -5,8 +5,8 @@ import (
 	"sort"
 	"strings"
 
-	"github.com/fabxc/tsdb/chunks"
-	"github.com/fabxc/tsdb/labels"
+	"github.com/prometheus/tsdb/chunks"
+	"github.com/prometheus/tsdb/labels"
 )
 
 // Querier provides querying access over time series data of a fixed
@@ -258,6 +258,9 @@ func (nopSeriesSet) Next() bool { return false }
 func (nopSeriesSet) At() Series { return nil }
 func (nopSeriesSet) Err() error { return nil }
 
+// mergedSeriesSet takes two series sets as a single series set. The input series sets
+// must be sorted and sequential in time, i.e. if they have the same label set,
+// the datapoints of a must be before the datapoints of b.
 type mergedSeriesSet struct {
 	a, b SeriesSet
 
@@ -307,11 +310,9 @@ func (s *mergedSeriesSet) Next() bool {
 	if d > 0 {
 		s.cur = s.b.At()
 		s.bdone = !s.b.Next()
-
 	} else if d < 0 {
 		s.cur = s.a.At()
 		s.adone = !s.a.Next()
-
 	} else {
 		s.cur = &chainedSeries{series: []Series{s.a.At(), s.b.At()}}
 		s.adone = !s.a.Next()

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

@@ -13,9 +13,9 @@ import (
 	"time"
 
 	"github.com/coreos/etcd/pkg/fileutil"
-	"github.com/fabxc/tsdb/labels"
 	"github.com/go-kit/kit/log"
 	"github.com/pkg/errors"
+	"github.com/prometheus/tsdb/labels"
 )
 
 // WALEntryType indicates what data a WAL entry contains.

vendor/vendor.json

@@ -361,12 +361,6 @@
 			"revision": "c589d0c9f0d81640c518354c7bcae77d99820aa3",
 			"revisionTime": "2016-09-30T00:14:02Z"
 		},
-		{
-			"checksumSHA1": "bBLYUZL/ZfgLqOPlBCkA88QahFQ=",
-			"path": "github.com/fabxc/tsdb",
-			"revision": "1afd8080f78b4925d2d6824eb8b6df333e549160",
-			"revisionTime": "2017-03-31T11:53:02Z"
-		},
 		{
 			"checksumSHA1": "uVzWuLvF646YjiKomsc2CR1ua58=",
 			"path": "github.com/fabxc/tsdb/chunks",
@@ -647,6 +641,24 @@
 			"revision": "abf152e5f3e97f2fafac028d2cc06c1feb87ffa5",
 			"revisionTime": "2016-04-11T19:08:41Z"
 		},
+		{
+			"checksumSHA1": "yKs0vGrGUdwhgmXGWY6We0O75hY=",
+			"path": "github.com/prometheus/tsdb",
+			"revision": "10c7c9acbe0175a411bce90cd7a0d9d7a13d6a83",
+			"revisionTime": "2017-04-04T09:27:26Z"
+		},
+		{
+			"checksumSHA1": "Qwlzvcx5Lbo9Nzb75AGgiiGszZI=",
+			"path": "github.com/prometheus/tsdb/chunks",
+			"revision": "10c7c9acbe0175a411bce90cd7a0d9d7a13d6a83",
+			"revisionTime": "2017-04-04T09:27:26Z"
+		},
+		{
+			"checksumSHA1": "7ztYi9KP5X3X7+1u7PmRQRXMGZU=",
+			"path": "github.com/prometheus/tsdb/labels",
+			"revision": "10c7c9acbe0175a411bce90cd7a0d9d7a13d6a83",
+			"revisionTime": "2017-04-04T09:27:26Z"
+		},
 		{
 			"checksumSHA1": "+49Vr4Me28p3cR+gxX5SUQHbbas=",
 			"path": "github.com/samuel/go-zookeeper/zk",