Merge #51607

51607: kvserver: return destination from AdminScatter r=pbardea a=pbardea

This commit updates the AdminScatter request to return the node of the
leaseholder after the scattering for each range that is scattered in the
request.

Release note: None

Co-authored-by: Paul Bardea <pbardea@gmail.com>

pkg/kv/kvserver/replica_command.go

@@ -2395,14 +2395,23 @@ func (r *Replica) adminScatter(
  }
  }
 
- desc := r.Desc()
+ desc, lease := r.GetDescAndLease(ctx)
  return roachpb.AdminScatterResponse{
- Ranges: []roachpb.AdminScatterResponse_Range{{
- Span: roachpb.Span{
- Key: desc.StartKey.AsRawKey(),
- EndKey: desc.EndKey.AsRawKey(),
+ // TODO(pbardea): This is here for compatibility with 20.1, remove in 21.1.
+ DeprecatedRanges: []roachpb.AdminScatterResponse_Range{
+ {
+ Span: roachpb.Span{
+ Key: desc.StartKey.AsRawKey(),
+ EndKey: desc.EndKey.AsRawKey(),
+ },
+ },
+ },
+ RangeInfos: []roachpb.RangeInfo{
+ {
+ Desc: desc,
+ Lease: lease,
  },
- }},
+ },
  }, nil
 }
 

pkg/roachpb/api.go

@@ -402,11 +402,40 @@ func (r *AdminScatterResponse) combine(c combinable) error {
  if err := r.ResponseHeader.combine(otherR.Header()); err != nil {
  return err
  }
- r.Ranges = append(r.Ranges, otherR.Ranges...)
+
+ // Combined responses will always have only RangeInfo set, rather than
+ // DeprecatedRanges.
+ // TODO(pbardea): Remove in 21.1.
+ r.maybeUpgrade()
+ otherR.maybeUpgrade()
+ r.RangeInfos = append(r.RangeInfos, otherR.RangeInfos...)
  }
  return nil
 }
 
+// maybeUpgrade will upgrade responses from 20.1 clients to look like 20.2
+// responses.
+// It converts the DeprecatedRanges field of the response to the equivalent
+// RangeInfos and nils out DeprecatedRanges. Note that the converted RangeInfos
+// will have an empty lease and only have the start and end key of the range
+// descriptor populated.
+func (r *AdminScatterResponse) maybeUpgrade() {
+ if len(r.RangeInfos) == 0 {
+ r.RangeInfos = make([]RangeInfo, len(r.DeprecatedRanges))
+ for i, respRange := range r.DeprecatedRanges {
+ r.RangeInfos[i] = RangeInfo{
+ // respRange.Span's keys are not local keys. The keys were created with
+ // AsRawKey(), so converting back is safe.
+ Desc: RangeDescriptor{
+ StartKey: RKey(respRange.Span.Key),
+ EndKey: RKey(respRange.Span.EndKey),
+ },
+ }
+ }
+ }
+ r.DeprecatedRanges = nil
+}
+
 var _ combinable = &AdminScatterResponse{}
 
 // Header implements the Request interface.