fix: handle stall metrics

src/mito2/src/worker.rs

@@ -795,12 +795,10 @@ impl<S: LogStore> RegionWorkerLoop<S> {
             let handle_start = Instant::now();
 
             if self.flush_receiver.has_changed().unwrap_or(false) {
-                let start = Instant::now();
                 // Always checks whether we could process stalled requests to avoid a request
                 // hangs too long.
                 // If the channel is closed, do nothing.
                 self.handle_stalled_requests().await;
-                self.metrics.handle_stall_cost = start.elapsed();
             }
 
             // Try to recv more requests from the channel.

src/mito2/src/worker/handle_write.rs

@@ -131,6 +131,7 @@ impl<S: LogStore> RegionWorkerLoop<S> {
 
     /// Handles all stalled write requests.
     pub(crate) async fn handle_stalled_requests(&mut self) {
+        let handle_stall_start = Instant::now();
         if let Some(start) = self.stall_start.take() {
             self.metrics.stall_cost += start.elapsed();
         }
@@ -142,6 +143,7 @@ impl<S: LogStore> RegionWorkerLoop<S> {
             self.metrics.num_stalled_request_processed += requests.len();
             self.handle_write_requests(requests, false).await;
         }
+        self.metrics.handle_stall_cost += handle_stall_start.elapsed();
     }
 
     /// Rejects all stalled requests.