[no-release-notes] go: nbs,remotesrv: Cleanup and comments for AddTableFilesToManifest ref checks PR.

go/libraries/doltcore/remotesrv/grpc.go

@@ -654,6 +654,11 @@ func (rs *RemoteChunkStore) AddTableFiles(ctx context.Context, req *remotesapi.A
 	return &remotesapi.AddTableFilesResponse{Success: true}, nil
 }
 
+// Returns a |chunks.GetAddrsCurry| for the nbf (NomsBinFormat)
+// corresponding to |version|.
+//
+// Used to implement chunk reference sanity checks when adding table files that have
+// been uploaded by clients to the stores managed by the gRPC server.
 func (rs *RemoteChunkStore) getAddrs(version string) chunks.GetAddrsCurry {
 	fmt, err := types.GetFormatForVersionString(version)
 	if err != nil {

go/store/nbs/journal.go

@@ -195,6 +195,14 @@ func trueUpBackingManifest(ctx context.Context, root hash.Hash, backing *journal
 	if err != nil {
 		return manifestContents{}, err
 	} else if !ok {
+		// If there is no backing manifest yet, we simply
+		// return without any manifest contents. We can open a
+		// newly created (cloned) journal file before the
+		// manifest corresponding to its existence has been
+		// created. |*ChunkJournal.ParseIfExists| forwards
+		// to the backing store in the case that the loaded
+		// manifest is currently empty, so eventually the
+		// manifest will be created.
 		return manifestContents{}, nil
 	}
 

go/store/nbs/table_set.go

@@ -440,6 +440,8 @@ func (ts tableSet) openForAdd(ctx context.Context, files map[hash.Hash]uint32, s
 			source.close()
 		}
 	}
+	// First add clones of all sources that are already present in
+	// ts.novel or ts.upstream.
 	for h := range files {
 		if s, ok := ts.novel[h]; ok {
 			cloned, err := s.clone()
@@ -457,16 +459,24 @@ func (ts tableSet) openForAdd(ctx context.Context, files map[hash.Hash]uint32, s
 			ret[h] = cloned
 		}
 	}
+	// Concurrently open all files that are not already
+	// in |ret|.
 	eg, ctx := errgroup.WithContext(ctx)
 	var mu sync.Mutex
-	for h, c := range files {
+	for fileId, chunkCount := range files {
+		mu.Lock()
+		_, ok := ret[fileId]
+		mu.Unlock()
+		if ok {
+			continue
+		}
 		eg.Go(func() error {
-			cs, err := ts.p.Open(ctx, h, c, stats)
+			cs, err := ts.p.Open(ctx, fileId, chunkCount, stats)
 			if err != nil {
 				return err
 			}
 			mu.Lock()
-			ret[h] = cs
+			ret[fileId] = cs
 			mu.Unlock()
 			return nil
 		})