Golang Iterator.RawValue方法代码示例

// Apply implements the Processor interface.
func (p *DeletionProcessor) Apply(sampleIterator leveldb.Iterator, samplesPersistence raw.Persistence, stopAt clientmodel.Timestamp, fingerprint *clientmodel.Fingerprint) (lastCurated clientmodel.Timestamp, err error) {
	var pendingBatch raw.Batch

	defer func() {
		if pendingBatch != nil {
			pendingBatch.Close()
		}
	}()

	sampleKeyDto, _ := p.dtoSampleKeys.Get()
	defer p.dtoSampleKeys.Give(sampleKeyDto)

	sampleKey, _ := p.sampleKeys.Get()
	defer p.sampleKeys.Give(sampleKey)

	if err = sampleIterator.Key(sampleKeyDto); err != nil {
		return
	}
	sampleKey.Load(sampleKeyDto)

	sampleValues := unmarshalValues(sampleIterator.RawValue(), nil)

	pendingMutations := 0

	for lastCurated.Before(stopAt) && sampleKey.Fingerprint.Equal(fingerprint) {
		switch {
		// Furnish a new pending batch operation if none is available.
		case pendingBatch == nil:
			pendingBatch = leveldb.NewBatch()

		// If there are no sample values to extract from the datastore,
		// let's continue extracting more values to use.  We know that
		// the time.Before() block would prevent us from going into
		// unsafe territory.
		case len(sampleValues) == 0:
			if !sampleIterator.Next() {
				return lastCurated, fmt.Errorf("illegal condition: invalid iterator on continuation")
			}

			if err = sampleIterator.Key(sampleKeyDto); err != nil {
				return
			}
			sampleKey.Load(sampleKeyDto)

			sampleValues = unmarshalValues(sampleIterator.RawValue(), nil)

		// If the number of pending mutations exceeds the allowed batch
		// amount, commit to disk and delete the batch.  A new one will
		// be recreated if necessary.
		case pendingMutations >= p.maximumMutationPoolBatch:
			err = samplesPersistence.Commit(pendingBatch)
			if err != nil {
				return
			}

			pendingMutations = 0

			pendingBatch.Close()
			pendingBatch = nil

		case !sampleKey.MayContain(stopAt):
			k := &dto.SampleKey{}
			sampleKey.Dump(k)
			pendingBatch.Drop(k)
			lastCurated = sampleKey.LastTimestamp
			sampleValues = metric.Values{}
			pendingMutations++

		case sampleKey.MayContain(stopAt):
			k := &dto.SampleKey{}
			sampleKey.Dump(k)
			pendingBatch.Drop(k)
			pendingMutations++

			sampleValues = sampleValues.TruncateBefore(stopAt)
			if len(sampleValues) > 0 {
				k := &dto.SampleKey{}
				sampleKey = buildSampleKey(fingerprint, sampleValues)
				sampleKey.Dump(k)
				lastCurated = sampleKey.FirstTimestamp
				v := marshalValues(sampleValues, nil)
				pendingBatch.PutRaw(k, v)
				pendingMutations++
			} else {
				lastCurated = sampleKey.LastTimestamp
			}

		default:
			err = fmt.Errorf("unhandled processing case")
		}
	}

	// This is not deferred due to the off-chance that a pre-existing commit
	// failed.
	if pendingBatch != nil && pendingMutations > 0 {
		err = samplesPersistence.Commit(pendingBatch)
		if err != nil {
			return
		}
//.........这里部分代码省略.........

func (t *TieredStorage) loadChunkAroundTime(
	iterator leveldb.Iterator,
	fingerprint *clientmodel.Fingerprint,
	ts clientmodel.Timestamp,
	firstBlock,
	lastBlock *SampleKey,
) (chunk metric.Values, expired bool) {
	if fingerprint.Less(firstBlock.Fingerprint) {
		return nil, false
	}
	if lastBlock.Fingerprint.Less(fingerprint) {
		return nil, true
	}

	seekingKey, _ := t.sampleKeys.Get()
	defer t.sampleKeys.Give(seekingKey)

	seekingKey.Fingerprint = fingerprint

	if fingerprint.Equal(firstBlock.Fingerprint) && ts.Before(firstBlock.FirstTimestamp) {
		seekingKey.FirstTimestamp = firstBlock.FirstTimestamp
	} else if fingerprint.Equal(lastBlock.Fingerprint) && ts.After(lastBlock.FirstTimestamp) {
		seekingKey.FirstTimestamp = lastBlock.FirstTimestamp
	} else {
		seekingKey.FirstTimestamp = ts
	}

	dto, _ := t.dtoSampleKeys.Get()
	defer t.dtoSampleKeys.Give(dto)

	seekingKey.Dump(dto)
	if !iterator.Seek(dto) {
		return chunk, true
	}

	var foundValues metric.Values

	if err := iterator.Key(dto); err != nil {
		panic(err)
	}
	seekingKey.Load(dto)

	if seekingKey.Fingerprint.Equal(fingerprint) {
		// Figure out if we need to rewind by one block.
		// Imagine the following supertime blocks with time ranges:
		//
		// Block 1: ft 1000 - lt 1009 <data>
		// Block 1: ft 1010 - lt 1019 <data>
		//
		// If we are aiming to find time 1005, we would first seek to the block with
		// supertime 1010, then need to rewind by one block by virtue of LevelDB
		// iterator seek behavior.
		//
		// Only do the rewind if there is another chunk before this one.
		if !seekingKey.MayContain(ts) {
			postValues := unmarshalValues(iterator.RawValue(), nil)
			if !seekingKey.Equal(firstBlock) {
				if !iterator.Previous() {
					panic("This should never return false.")
				}

				if err := iterator.Key(dto); err != nil {
					panic(err)
				}
				seekingKey.Load(dto)

				if !seekingKey.Fingerprint.Equal(fingerprint) {
					return postValues, false
				}

				foundValues = unmarshalValues(iterator.RawValue(), nil)
				foundValues = append(foundValues, postValues...)
				return foundValues, false
			}
		}

		foundValues = unmarshalValues(iterator.RawValue(), nil)
		return foundValues, false
	}

	if fingerprint.Less(seekingKey.Fingerprint) {
		if !seekingKey.Equal(firstBlock) {
			if !iterator.Previous() {
				panic("This should never return false.")
			}

			if err := iterator.Key(dto); err != nil {
				panic(err)
			}
			seekingKey.Load(dto)

			if !seekingKey.Fingerprint.Equal(fingerprint) {
				return nil, false
			}

			foundValues = unmarshalValues(iterator.RawValue(), nil)
			return foundValues, false
		}
	}

//.........这里部分代码省略.........