etcdserver: set sort ASCEND for empty sort order

when target is not key
etcd-io · Oct 18, 2016 · e1fde10 · e1fde10
1 parent 20bdb31
commit e1fde10
Showing 1 changed file with 10 additions and 4 deletions.
diff --git a/etcdserver/apply.go b/etcdserver/apply.go
@@ -304,7 +304,14 @@ func (a *applierV3backend) Range(txnID int64, r *pb.RangeRequest) (*pb.RangeResp
 		pruneKVs(rr, f)
 	}
 
-	if r.SortOrder != pb.RangeRequest_NONE {
+	sortOrder := r.SortOrder
+	if r.SortTarget != pb.RangeRequest_KEY && sortOrder == pb.RangeRequest_NONE {
+		// Since current mvcc.Range implementation returns results
+		// sorted by keys in lexiographically ascending order,
+		// sort ASCEND by default only when target is not 'KEY'
+		sortOrder = pb.RangeRequest_ASCEND
+	}
+	if sortOrder != pb.RangeRequest_NONE {
 		var sorter sort.Interface
 		switch {
 		case r.SortTarget == pb.RangeRequest_KEY:
@@ -319,13 +326,12 @@ func (a *applierV3backend) Range(txnID int64, r *pb.RangeRequest) (*pb.RangeResp
 			sorter = &kvSortByValue{&kvSort{rr.KVs}}
 		}
 		switch {
-		case r.SortOrder == pb.RangeRequest_ASCEND:
+		case sortOrder == pb.RangeRequest_ASCEND:
 			sort.Sort(sorter)
-		case r.SortOrder == pb.RangeRequest_DESCEND:
+		case sortOrder == pb.RangeRequest_DESCEND:
 			sort.Sort(sort.Reverse(sorter))
 		}
 	}
-
 	if r.Limit > 0 && len(rr.KVs) > int(r.Limit) {
 		rr.KVs = rr.KVs[:r.Limit]
 		resp.More = true