Merge remote-tracking branch 'upstream/master' into metrics-add-names…

…pace-label

# Conflicts:
#	cdc/contextutil/ctx.go
#	cdc/entry/mounter.go
#	cdc/kv/client.go
#	cdc/kv/region_worker.go
#	cdc/kv/token_region.go
#	cdc/model/changefeed.go
#	cdc/owner/changefeed.go
#	cdc/owner/owner.go
#	cdc/processor/pipeline/sorter.go
#	cdc/processor/processor.go
#	cdc/puller/puller.go
#	cdc/redo/writer/file.go
#	cdc/redo/writer/file_test.go
#	cdc/redo/writer/writer.go
#	cdc/sink/buffer_sink.go
#	cdc/sink/metrics/statistics.go
#	cdc/sink/mq/producer/kafka/metrics.go
#	cdc/sink/mysql/mysql.go
#	cdc/sink/sink_manager.go
#	cdc/sorter/leveldb/sorter.go
#	cdc/sorter/memory/entry_sorter.go
#	cdc/sorter/unified/heap_sorter.go
#	cdc/sorter/unified/merger.go
#	cdc/sorter/unified/unified_sorter.go

cdc/contextutil/ctx.go

@@ -110,7 +110,7 @@ func IsOwnerFromCtx(ctx context.Context) bool {
 }
 
 // ChangefeedIDFromCtx returns a changefeedID stored in the specified context.
-// It returns an empty model.changefeedID if there's not a changefeedID.
+// It returns an empty model.changefeedID if there's no changefeedID found.
 func ChangefeedIDFromCtx(ctx context.Context) model.ChangeFeedID {
 	changefeedID, ok := ctx.Value(ctxKeyChangefeedID).(model.ChangeFeedID)
 	if !ok {

cdc/model/changefeed.go

@@ -37,6 +37,8 @@ const DefaultNamespace = "default"
 
 // ChangeFeedID is the type for change feed ID
 type ChangeFeedID struct {
+	// Namespace and ID pair is unique in one ticdc cluster
+	// the default value of Namespace is "default"
 	Namespace string
 	ID        string
 }