// 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)
}
}
