diff --git a/app/vmselect/netstorage/tmp_blocks_file.go b/app/vmselect/netstorage/tmp_blocks_file.go
index 3667d12b4..9f6f072ed 100644
--- a/app/vmselect/netstorage/tmp_blocks_file.go
+++ b/app/vmselect/netstorage/tmp_blocks_file.go
@@ -36,6 +36,9 @@ func maxInmemoryTmpBlocksFile() int {
 	if maxLen < 64*1024 {
 		return 64 * 1024
 	}
+	if maxLen > 4*1024*1024 {
+		return 4*1024*1024
+	}
 	return maxLen
 }