diff --git a/Cargo.lock b/Cargo.lock
index d42e699cbb..6fcfb0d990 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3822,7 +3822,7 @@ checksum = "d2fabcfbdc87f4758337ca535fb41a6d701b65693ce38287d856d1674551ec9b"
 [[package]]
 name = "greptime-proto"
 version = "0.1.0"
-source = "git+https://github.com/GreptimeTeam/greptime-proto.git?rev=e8abf8241c908448dce595399e89c89a40d048bd#e8abf8241c908448dce595399e89c89a40d048bd"
+source = "git+https://github.com/GreptimeTeam/greptime-proto.git?rev=1552a21e77752f1baf8062b937584b80de84e0b3#1552a21e77752f1baf8062b937584b80de84e0b3"
 dependencies = [
  "prost",
  "tonic 0.9.2",
diff --git a/src/api/Cargo.toml b/src/api/Cargo.toml
index b4b0523959..d8e718b73e 100644
--- a/src/api/Cargo.toml
+++ b/src/api/Cargo.toml
@@ -10,7 +10,7 @@ common-base = { path = "../common/base" }
 common-error = { path = "../common/error" }
 common-time = { path = "../common/time" }
 datatypes = { path = "../datatypes" }
-greptime-proto = { git = "https://github.com/GreptimeTeam/greptime-proto.git", rev = "e8abf8241c908448dce595399e89c89a40d048bd" }
+greptime-proto = { git = "https://github.com/GreptimeTeam/greptime-proto.git", rev = "1552a21e77752f1baf8062b937584b80de84e0b3" }
 prost.workspace = true
 snafu = { version = "0.7", features = ["backtraces"] }
 tonic.workspace = true
diff --git a/src/meta-srv/src/handler.rs b/src/meta-srv/src/handler.rs
index 98fbca803d..a0b0c38e52 100644
--- a/src/meta-srv/src/handler.rs
+++ b/src/meta-srv/src/handler.rs
@@ -73,9 +73,9 @@ pub struct HeartbeatAccumulator {
 }
 
 impl HeartbeatAccumulator {
-    pub fn into_mailbox_messages(self) -> Vec<MailboxMessage> {
+    pub fn into_mailbox_message(self) -> Option<MailboxMessage> {
         // TODO(jiachun): to HeartbeatResponse payload
-        vec![]
+        None
     }
 }
 
@@ -173,7 +173,7 @@ impl HeartbeatHandlerGroup {
         let header = std::mem::take(&mut acc.header);
         let res = HeartbeatResponse {
             header,
-            mailbox_messages: acc.into_mailbox_messages(),
+            mailbox_message: acc.into_mailbox_message(),
         };
         Ok(res)
     }
@@ -275,7 +275,7 @@ impl Mailbox for HeartbeatMailbox {
         msg.id = message_id;
         let res = HeartbeatResponse {
             header: Some(header),
-            mailbox_messages: vec![msg],
+            mailbox_message: Some(msg),
         };
 
         pusher.push(res).await?;
@@ -376,8 +376,9 @@ mod tests {
             .unwrap();
 
         let recv_obj = pusher_rx.recv().await.unwrap().unwrap();
-        assert_eq!(recv_obj.mailbox_messages[0].timestamp_millis, 123);
-        assert_eq!(recv_obj.mailbox_messages[0].subject, "req-test".to_string());
+        let message = recv_obj.mailbox_message.unwrap();
+        assert_eq!(message.timestamp_millis, 123);
+        assert_eq!(message.subject, "req-test".to_string());
 
         (mailbox, receiver)
     }
diff --git a/src/meta-srv/src/handler/mailbox_handler.rs b/src/meta-srv/src/handler/mailbox_handler.rs
index 6bcc0ff4c8..973e869411 100644
--- a/src/meta-srv/src/handler/mailbox_handler.rs
+++ b/src/meta-srv/src/handler/mailbox_handler.rs
@@ -33,13 +33,8 @@ impl HeartbeatHandler for MailboxHandler {
         ctx: &mut Context,
         _acc: &mut HeartbeatAccumulator,
     ) -> Result<()> {
-        if req.mailbox_messages.is_empty() {
-            return Ok(());
-        }
-
-        let mailbox_messages = req.mailbox_messages.clone();
-        for msg in mailbox_messages {
-            ctx.mailbox.on_recv(msg.id, Ok(msg)).await?;
+        if let Some(message) = &req.mailbox_message {
+            ctx.mailbox.on_recv(message.id, Ok(message.clone())).await?;
         }
 
         Ok(())
diff --git a/src/meta-srv/src/handler/response_header_handler.rs b/src/meta-srv/src/handler/response_header_handler.rs
index 733c086129..28fffa3c29 100644
--- a/src/meta-srv/src/handler/response_header_handler.rs
+++ b/src/meta-srv/src/handler/response_header_handler.rs
@@ -90,7 +90,7 @@ mod tests {
         let header = std::mem::take(&mut acc.header);
         let res = HeartbeatResponse {
             header,
-            mailbox_messages: acc.into_mailbox_messages(),
+            mailbox_message: acc.into_mailbox_message(),
         };
         assert_eq!(1, res.header.unwrap().cluster_id);
     }