Пример #1
0
// loadChunks loads a group of chunks of a timeseries by their index. The chunk
// with the earliest time will have index 0, the following ones will have
// incrementally larger indexes. The indexOffset denotes the offset to be added to
// each index in indexes. It is the caller's responsibility to not persist or
// drop anything for the same fingerprint concurrently.
func (p *persistence) loadChunks(fp model.Fingerprint, indexes []int, indexOffset int) ([]chunk.Chunk, error) {
	f, err := p.openChunkFileForReading(fp)
	if err != nil {
		return nil, err
	}
	defer f.Close()

	chunks := make([]chunk.Chunk, 0, len(indexes))
	buf := p.bufPool.Get().([]byte)
	defer func() {
		// buf may change below. An unwrapped 'defer p.bufPool.Put(buf)'
		// would only put back the original buf.
		p.bufPool.Put(buf)
	}()

	for i := 0; i < len(indexes); i++ {
		// This loads chunks in batches. A batch is a streak of
		// consecutive chunks, read from disk in one go.
		batchSize := 1
		if _, err := f.Seek(offsetForChunkIndex(indexes[i]+indexOffset), os.SEEK_SET); err != nil {
			return nil, err
		}

		for ; batchSize < chunkMaxBatchSize &&
			i+1 < len(indexes) &&
			indexes[i]+1 == indexes[i+1]; i, batchSize = i+1, batchSize+1 {
		}
		readSize := batchSize * chunkLenWithHeader
		if cap(buf) < readSize {
			buf = make([]byte, readSize)
		}
		buf = buf[:readSize]

		if _, err := io.ReadFull(f, buf); err != nil {
			return nil, err
		}
		for c := 0; c < batchSize; c++ {
			chunk, err := chunk.NewForEncoding(chunk.Encoding(buf[c*chunkLenWithHeader+chunkHeaderTypeOffset]))
			if err != nil {
				return nil, err
			}
			if err := chunk.UnmarshalFromBuf(buf[c*chunkLenWithHeader+chunkHeaderLen:]); err != nil {
				return nil, err
			}
			chunks = append(chunks, chunk)
		}
	}
	chunk.Ops.WithLabelValues(chunk.Load).Add(float64(len(chunks)))
	atomic.AddInt64(&chunk.NumMemChunks, int64(len(chunks)))
	return chunks, nil
}
Пример #2
0
// scan works like bufio.Scanner.Scan.
func (hs *headsScanner) scan() bool {
	if hs.seriesCurrent == hs.seriesTotal || hs.err != nil {
		return false
	}

	var (
		seriesFlags      byte
		fpAsInt          uint64
		metric           codable.Metric
		persistWatermark int64
		modTimeNano      int64
		modTime          time.Time
		chunkDescsOffset int64
		savedFirstTime   int64
		numChunkDescs    int64
		firstTime        int64
		lastTime         int64
		encoding         byte
		ch               chunk.Chunk
		lastTimeHead     model.Time
	)
	if seriesFlags, hs.err = hs.r.ReadByte(); hs.err != nil {
		return false
	}
	headChunkPersisted := seriesFlags&flagHeadChunkPersisted != 0
	if fpAsInt, hs.err = codable.DecodeUint64(hs.r); hs.err != nil {
		return false
	}
	hs.fp = model.Fingerprint(fpAsInt)

	if hs.err = metric.UnmarshalFromReader(hs.r); hs.err != nil {
		return false
	}
	if hs.version != headsFormatLegacyVersion {
		// persistWatermark only present in v2.
		persistWatermark, hs.err = binary.ReadVarint(hs.r)
		if hs.err != nil {
			return false
		}
		modTimeNano, hs.err = binary.ReadVarint(hs.r)
		if hs.err != nil {
			return false
		}
		if modTimeNano != -1 {
			modTime = time.Unix(0, modTimeNano)
		}
	}
	if chunkDescsOffset, hs.err = binary.ReadVarint(hs.r); hs.err != nil {
		return false
	}
	if savedFirstTime, hs.err = binary.ReadVarint(hs.r); hs.err != nil {
		return false
	}

	if numChunkDescs, hs.err = binary.ReadVarint(hs.r); hs.err != nil {
		return false
	}
	chunkDescs := make([]*chunk.Desc, numChunkDescs)
	if hs.version == headsFormatLegacyVersion {
		if headChunkPersisted {
			persistWatermark = numChunkDescs
		} else {
			persistWatermark = numChunkDescs - 1
		}
	}
	headChunkClosed := true // Initial assumption.
	for i := int64(0); i < numChunkDescs; i++ {
		if i < persistWatermark {
			if firstTime, hs.err = binary.ReadVarint(hs.r); hs.err != nil {
				return false
			}
			if lastTime, hs.err = binary.ReadVarint(hs.r); hs.err != nil {
				return false
			}
			chunkDescs[i] = &chunk.Desc{
				ChunkFirstTime: model.Time(firstTime),
				ChunkLastTime:  model.Time(lastTime),
			}
			chunk.NumMemDescs.Inc()
		} else {
			// Non-persisted chunk.
			// If there are non-persisted chunks at all, we consider
			// the head chunk not to be closed yet.
			headChunkClosed = false
			if encoding, hs.err = hs.r.ReadByte(); hs.err != nil {
				return false
			}
			if ch, hs.err = chunk.NewForEncoding(chunk.Encoding(encoding)); hs.err != nil {
				return false
			}
			if hs.err = ch.Unmarshal(hs.r); hs.err != nil {
				return false
			}
			cd := chunk.NewDesc(ch, ch.FirstTime())
			if i < numChunkDescs-1 {
				// This is NOT the head chunk. So it's a chunk
				// to be persisted, and we need to populate lastTime.
				hs.chunksToPersistTotal++
				cd.MaybePopulateLastTime()
			}
			chunkDescs[i] = cd
		}
	}

	if lastTimeHead, hs.err = chunkDescs[len(chunkDescs)-1].LastTime(); hs.err != nil {
		return false
	}

	hs.series = &memorySeries{
		metric:           model.Metric(metric),
		chunkDescs:       chunkDescs,
		persistWatermark: int(persistWatermark),
		modTime:          modTime,
		chunkDescsOffset: int(chunkDescsOffset),
		savedFirstTime:   model.Time(savedFirstTime),
		lastTime:         lastTimeHead,
		headChunkClosed:  headChunkClosed,
	}
	hs.seriesCurrent++
	return true
}