naming

tsdb/engine/tsm1/engine.go

@@ -1563,7 +1563,7 @@ func (e *Engine) CreateIterator(measurement string, opt query.IteratorOptions) (
 				if err != nil {
 					return nil, err
 				}
-				return newMergeGuardIterator(itrs, opt)
+				return newMergeFinalizerIterator(itrs, opt)
 			}
 		}
 
@@ -1573,14 +1573,14 @@ func (e *Engine) CreateIterator(measurement string, opt query.IteratorOptions) (
 		} else if len(inputs) == 0 {
 			return nil, nil
 		}
-		return newMergeGuardIterator(inputs, opt)
+		return newMergeFinalizerIterator(inputs, opt)
 	}
 
 	itrs, err := e.createVarRefIterator(measurement, opt)
 	if err != nil {
 		return nil, err
 	}
-	return newMergeGuardIterator(itrs, opt)
+	return newMergeFinalizerIterator(itrs, opt)
 }
 
 func (e *Engine) createCallIterator(measurement string, call *influxql.Call, opt query.IteratorOptions) ([]query.Iterator, error) {

tsdb/engine/tsm1/iterator.go

@@ -149,9 +149,10 @@ func (c cursorsAt) close() {
 	}
 }
 
-// newMergeGuardIterator creates a new Merge iterator from the inputs. If Merge returns an error,
-// the inputs will be closed
-func newMergeGuardIterator(inputs []query.Iterator, opt query.IteratorOptions) (query.Iterator, error) {
+// newMergeFinalizerIterator creates a new Merge iterator from the inputs. If the call to Merge succeeds,
+// the resulting Iterator will be wrapped in a finalizer iterator.
+// If Merge returns an error, the inputs will be closed.
+func newMergeFinalizerIterator(inputs []query.Iterator, opt query.IteratorOptions) (query.Iterator, error) {
 	itr, err := query.Iterators(inputs).Merge(opt)
 	if err != nil {
 		query.Iterators(inputs).Close()