diff --git a/proto/greptime/v1/region/server.proto b/proto/greptime/v1/region/server.proto
index 75965253..eab6b09b 100644
--- a/proto/greptime/v1/region/server.proto
+++ b/proto/greptime/v1/region/server.proto
@@ -106,7 +106,13 @@ message CreateRequest {
 // Same as CreateRequests, but for dropping regions.
 message DropRequests { repeated DropRequest requests = 1; }
 
-message DropRequest { uint64 region_id = 1; }
+message DropRequest { 
+  uint64 region_id = 1;
+  // Only used by Metric Engine, for fast path drop.
+  // It only works for Metric Engine, and will be ignored by other engines.
+  // If true, the Metric Engine will delete logical tables in memory, and drop the physical region eventually.
+  bool fast_path = 2;
+}
 
 message OpenRequest {
   uint64 region_id = 1;