Golang RKey.AsRawKey方法代碼示例

// RangeLookup implements the RangeDescriptorDB interface.
// RangeLookup dispatches a RangeLookup request for the given metadata
// key to the replicas of the given range. Note that we allow
// inconsistent reads when doing range lookups for efficiency. Getting
// stale data is not a correctness problem but instead may
// infrequently result in additional latency as additional range
// lookups may be required. Note also that rangeLookup bypasses the
// DistSender's Send() method, so there is no error inspection and
// retry logic here; this is not an issue since the lookup performs a
// single inconsistent read only.
func (ds *DistSender) RangeLookup(
	ctx context.Context, key roachpb.RKey, desc *roachpb.RangeDescriptor, useReverseScan bool,
) ([]roachpb.RangeDescriptor, []roachpb.RangeDescriptor, *roachpb.Error) {
	ba := roachpb.BatchRequest{}
	ba.ReadConsistency = roachpb.INCONSISTENT
	ba.Add(&roachpb.RangeLookupRequest{
		Span: roachpb.Span{
			// We can interpret the RKey as a Key here since it's a metadata
			// lookup; those are never local.
			Key: key.AsRawKey(),
		},
		MaxRanges: ds.rangeLookupMaxRanges,
		Reverse:   useReverseScan,
	})
	replicas := newReplicaSlice(ds.gossip, desc)
	replicas.Shuffle()
	br, err := ds.sendRPC(ctx, desc.RangeID, replicas, ba)
	if err != nil {
		return nil, nil, roachpb.NewError(err)
	}
	if br.Error != nil {
		return nil, nil, br.Error
	}
	resp := br.Responses[0].GetInner().(*roachpb.RangeLookupResponse)
	return resp.Ranges, resp.PrefetchedRanges, nil
}

// LookupReplica looks up replica by key [range]. Lookups are done
// by consulting each store in turn via Store.LookupReplica(key).
// Returns RangeID and replica on success; RangeKeyMismatch error
// if not found.
// If end is nil, a replica containing start is looked up.
// This is only for testing usage; performance doesn't matter.
func (ls *Stores) LookupReplica(
	start, end roachpb.RKey,
) (roachpb.RangeID, roachpb.ReplicaDescriptor, error) {
	ls.mu.RLock()
	defer ls.mu.RUnlock()
	var rangeID roachpb.RangeID
	var repDesc roachpb.ReplicaDescriptor
	var repDescFound bool
	for _, store := range ls.storeMap {
		replica := store.LookupReplica(start, nil)
		if replica == nil {
			continue
		}

		// Verify that the descriptor contains the entire range.
		if desc := replica.Desc(); !desc.ContainsKeyRange(start, end) {
			ctx := ls.AnnotateCtx(context.TODO())
			log.Warningf(ctx, "range not contained in one range: [%s,%s), but have [%s,%s)",
				start, end, desc.StartKey, desc.EndKey)
			err := roachpb.NewRangeKeyMismatchError(start.AsRawKey(), end.AsRawKey(), desc)
			return 0, roachpb.ReplicaDescriptor{}, err
		}

		rangeID = replica.RangeID

		var err error
		repDesc, err = replica.GetReplicaDescriptor()
		if err != nil {
			if _, ok := err.(*roachpb.RangeNotFoundError); ok {
				// We are not holding a lock across this block; the replica could have
				// been removed from the range (via down-replication) between the
				// LookupReplica and the GetReplicaDescriptor calls. In this case just
				// ignore this replica.
				continue
			}
			return 0, roachpb.ReplicaDescriptor{}, err
		}

		if repDescFound {
			// We already found the range; this should never happen outside of tests.
			err := errors.Errorf("range %+v exists on additional store: %+v", replica, store)
			return 0, roachpb.ReplicaDescriptor{}, err
		}

		repDescFound = true
	}
	if !repDescFound {
		return 0, roachpb.ReplicaDescriptor{}, roachpb.NewRangeNotFoundError(0)
	}
	return rangeID, repDesc, nil
}

// findTimeSeries searches the supplied engine over the supplied key range,
// identifying time series which have stored data in the range, along with the
// resolutions at which time series data is stored. A unique name/resolution
// pair will only be identified once, even if the range contains keys for that
// name/resolution pair at multiple timestamps or from multiple sources.
//
// An engine snapshot is used, rather than a client, because this function is
// intended to be called by a storage queue which can inspect the local data for
// a single range without the need for expensive network calls.
func findTimeSeries(
	snapshot engine.Reader, startKey, endKey roachpb.RKey, now hlc.Timestamp,
) ([]timeSeriesResolutionInfo, error) {
	var results []timeSeriesResolutionInfo

	iter := snapshot.NewIterator(false)
	defer iter.Close()

	// Set start boundary for the search, which is the lesser of the range start
	// key and the beginning of time series data.
	start := engine.MakeMVCCMetadataKey(startKey.AsRawKey())
	next := engine.MakeMVCCMetadataKey(keys.TimeseriesPrefix)
	if next.Less(start) {
		next = start
	}

	// Set end boundary for the search, which is the lesser of the range end key
	// and the end of time series data.
	end := engine.MakeMVCCMetadataKey(endKey.AsRawKey())
	lastTS := engine.MakeMVCCMetadataKey(keys.TimeseriesPrefix.PrefixEnd())
	if lastTS.Less(end) {
		end = lastTS
	}

	thresholds := computeThresholds(now.WallTime)

	for iter.Seek(next); iter.Valid() && iter.Less(end); iter.Seek(next) {
		foundKey := iter.Key().Key

		// Extract the name and resolution from the discovered key.
		name, _, res, tsNanos, err := DecodeDataKey(foundKey)
		if err != nil {
			return nil, err
		}
		// Skip this time series if there's nothing to prune. We check the
		// oldest (first) time series record's timestamp against the
		// pruning threshold.
		if threshold, ok := thresholds[res]; !ok || threshold > tsNanos {
			results = append(results, timeSeriesResolutionInfo{
				Name:       name,
				Resolution: res,
			})
		}

		// Set 'next' is initialized to the next possible time series key
		// which could belong to a previously undiscovered time series.
		next = engine.MakeMVCCMetadataKey(makeDataKeySeriesPrefix(name, res).PrefixEnd())
	}

	return results, nil
}

// findTimeSeries searches the supplied engine over the supplied key range,
// identifying time series which have stored data in the range, along with the
// resolutions at which time series data is stored. A unique name/resolution
// pair will only be identified once, even if the range contains keys for that
// name/resolution pair at multiple timestamps or from multiple sources.
//
// An engine snapshot is used, rather than a client, because this function is
// intended to be called by a storage queue which can inspect the local data for
// a single range without the need for expensive network calls.
func findTimeSeries(
	snapshot engine.Reader, startKey, endKey roachpb.RKey,
) ([]timeSeriesResolutionInfo, error) {
	var results []timeSeriesResolutionInfo

	iter := snapshot.NewIterator(false)
	defer iter.Close()

	// Set start boundary for the search, which is the lesser of the range start
	// key and the beginning of time series data.
	start := engine.MakeMVCCMetadataKey(startKey.AsRawKey())
	next := engine.MakeMVCCMetadataKey(keys.TimeseriesPrefix)
	if next.Less(start) {
		next = start
	}

	// Set end boundary for the search, which is the lesser of the range end key
	// and the end of time series data.
	end := engine.MakeMVCCMetadataKey(endKey.AsRawKey())
	lastTS := engine.MakeMVCCMetadataKey(keys.TimeseriesPrefix.PrefixEnd())
	if lastTS.Less(end) {
		end = lastTS
	}

	for iter.Seek(next); iter.Valid() && iter.Less(end); iter.Seek(next) {
		foundKey := iter.Key().Key

		// Extract the name and resolution from the discovered key.
		name, _, res, _, err := DecodeDataKey(foundKey)
		if err != nil {
			return nil, err
		}
		results = append(results, timeSeriesResolutionInfo{
			Name:       name,
			Resolution: res,
		})

		// Set 'next' is initialized to the next possible time series key
		// which could belong to a previously undiscovered time series.
		next = engine.MakeMVCCMetadataKey(makeDataKeySeriesPrefix(name, res).PrefixEnd())
	}

	return results, nil
}

// fillSkippedResponses after meeting the batch key max limit for range
// requests.
func fillSkippedResponses(ba roachpb.BatchRequest, br *roachpb.BatchResponse, nextKey roachpb.RKey) {
	// Some requests might have NoopResponses; we must replace them with empty
	// responses of the proper type.
	for i, req := range ba.Requests {
		if _, ok := br.Responses[i].GetInner().(*roachpb.NoopResponse); !ok {
			continue
		}
		var reply roachpb.Response
		switch t := req.GetInner().(type) {
		case *roachpb.ScanRequest:
			reply = &roachpb.ScanResponse{}

		case *roachpb.ReverseScanRequest:
			reply = &roachpb.ReverseScanResponse{}

		case *roachpb.DeleteRangeRequest:
			reply = &roachpb.DeleteRangeResponse{}

		case *roachpb.BeginTransactionRequest, *roachpb.EndTransactionRequest:
			continue

		default:
			panic(fmt.Sprintf("bad type %T", t))
		}
		union := roachpb.ResponseUnion{}
		union.MustSetInner(reply)
		br.Responses[i] = union
	}
	// Set the ResumeSpan for future batch requests.
	isReverse := ba.IsReverse()
	for i, resp := range br.Responses {
		req := ba.Requests[i].GetInner()
		if !roachpb.IsRange(req) {
			continue
		}
		hdr := resp.GetInner().Header()
		origSpan := req.Header()
		if isReverse {
			if hdr.ResumeSpan != nil {
				// The ResumeSpan.Key might be set to the StartKey of a range;
				// correctly set it to the Key of the original request span.
				hdr.ResumeSpan.Key = origSpan.Key
			} else if roachpb.RKey(origSpan.Key).Less(nextKey) {
				// Some keys have yet to be processed.
				hdr.ResumeSpan = &origSpan
				if nextKey.Less(roachpb.RKey(origSpan.EndKey)) {
					// The original span has been partially processed.
					hdr.ResumeSpan.EndKey = nextKey.AsRawKey()
				}
			}
		} else {
			if hdr.ResumeSpan != nil {
				// The ResumeSpan.EndKey might be set to the EndKey of a
				// range; correctly set it to the EndKey of the original
				// request span.
				hdr.ResumeSpan.EndKey = origSpan.EndKey
			} else if nextKey.Less(roachpb.RKey(origSpan.EndKey)) {
				// Some keys have yet to be processed.
				hdr.ResumeSpan = &origSpan
				if roachpb.RKey(origSpan.Key).Less(nextKey) {
					// The original span has been partially processed.
					hdr.ResumeSpan.Key = nextKey.AsRawKey()
				}
			}
		}
		br.Responses[i].GetInner().SetHeader(hdr)
	}
}