diff --git a/internal/datanode/compaction/clustering_compactor.go b/internal/datanode/compaction/clustering_compactor.go
index b92902f4a1..6071aaf5a1 100644
--- a/internal/datanode/compaction/clustering_compactor.go
+++ b/internal/datanode/compaction/clustering_compactor.go
@@ -714,8 +714,8 @@ func (t *clusteringCompactionTask) backgroundFlush(ctx context.Context) {
 			if signal.done {
 				t.doneChan <- struct{}{}
 			} else if signal.writer == nil {
-				err = t.flushLargestBuffers(ctx)
 				t.hasSignal.Store(false)
+				err = t.flushLargestBuffers(ctx)
 			} else {
 				future := t.flushPool.Submit(func() (any, error) {
 					err := t.flushBinlog(ctx, t.clusterBuffers[signal.id], signal.writer, signal.pack)