From b0cc058ba2d9003efac19a8e27651b63833a611a Mon Sep 17 00:00:00 2001
From: QuenKar <47681251+QuenKar@users.noreply.github.com>
Date: Tue, 9 Jan 2024 14:22:11 +0800
Subject: [PATCH] chore: cr comment

---
 src/mito2/src/cache/file_cache.rs  | 2 +-
 src/mito2/src/cache/write_cache.rs | 9 +++++++--
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/mito2/src/cache/file_cache.rs b/src/mito2/src/cache/file_cache.rs
index cee5b3dbe08e..94a8518dd1c0 100644
--- a/src/mito2/src/cache/file_cache.rs
+++ b/src/mito2/src/cache/file_cache.rs
@@ -213,7 +213,7 @@ pub(crate) type IndexKey = (RegionId, FileId);
 #[derive(Debug, Clone)]
 pub(crate) struct IndexValue {
     /// Size of the file in bytes.
-    pub file_size: u32,
+    pub(crate) file_size: u32,
 }
 
 /// Generates the path to the cached file.
diff --git a/src/mito2/src/cache/write_cache.rs b/src/mito2/src/cache/write_cache.rs
index e8afdd041bdf..bbb12b4c6483 100644
--- a/src/mito2/src/cache/write_cache.rs
+++ b/src/mito2/src/cache/write_cache.rs
@@ -101,6 +101,11 @@ impl WriteCache {
         timer.stop_and_record();
 
         // Upload sst file to remote object store.
+        if sst_info.is_none() {
+            // No data need to upload.
+            return Ok(None);
+        }
+
         let timer = FLUSH_ELAPSED.with_label_values(&["upload"]).start_timer();
 
         let reader = self
@@ -122,11 +127,11 @@ impl WriteCache {
             .await
             .context(error::UploadSstSnafu { region_id, file_id })?;
 
-        UPLOAD_BYTES_TOTAL.inc_by(bytes_written);
-
         // Must close to upload all data.
         writer.close().await.context(error::OpenDalSnafu)?;
 
+        UPLOAD_BYTES_TOTAL.inc_by(bytes_written);
+
         debug!(
             "Successfully upload file to remote, region: {}, file: {}, upload_path: {}, cost: {:?}s",
             region_id,