filer.sync: limit concurrency when fetching file chunks

fix https://github.com/seaweedfs/seaweedfs/issues/3787

weed/replication/sink/filersink/fetch_write.go

@@ -24,15 +24,17 @@ func (fs *FilerSink) replicateChunks(sourceChunks []*filer_pb.FileChunk, path st
 	var wg sync.WaitGroup
 	for chunkIndex, sourceChunk := range sourceChunks {
 		wg.Add(1)
-		go func(chunk *filer_pb.FileChunk, index int) {
-			defer wg.Done()
-			replicatedChunk, e := fs.replicateOneChunk(chunk, path)
-			if e != nil {
-				err = e
-				return
-			}
-			replicatedChunks[index] = replicatedChunk
-		}(sourceChunk, chunkIndex)
+		fs.executor.Execute(func() {
+			func(chunk *filer_pb.FileChunk, index int) {
+				defer wg.Done()
+				replicatedChunk, e := fs.replicateOneChunk(chunk, path)
+				if e != nil {
+					err = e
+					return
+				}
+				replicatedChunks[index] = replicatedChunk
+			}(sourceChunk, chunkIndex)
+		})
 	}
 	wg.Wait()
 

weed/replication/sink/filersink/filer_sink.go

@@ -32,6 +32,7 @@ type FilerSink struct {
 	address           string
 	writeChunkByFiler bool
 	isIncremental     bool
+	executor          *util.LimitedConcurrentExecutor
 }
 
 func init() {
@@ -53,6 +54,7 @@ func (fs *FilerSink) IsIncremental() bool {
 func (fs *FilerSink) Initialize(configuration util.Configuration, prefix string) error {
 	fs.isIncremental = configuration.GetBool(prefix + "is_incremental")
 	fs.dataCenter = configuration.GetString(prefix + "dataCenter")
+	fs.executor = util.NewLimitedConcurrentExecutor(32)
 	return fs.DoInitialize(
 		"",
 		configuration.GetString(prefix+"grpcAddress"),