diff --git a/be/src/io/fs/buffered_reader.cpp b/be/src/io/fs/buffered_reader.cpp
index e7f2cc9533..1c016a6b22 100644
--- a/be/src/io/fs/buffered_reader.cpp
+++ b/be/src/io/fs/buffered_reader.cpp
@@ -441,8 +441,6 @@ void PrefetchBuffer::prefetch_buffer() {
         _buffer_status = BufferStatus::PENDING;
         _prefetched.notify_all();
     }
-    _len = 0;
-    Status s;
 
     int read_range_index = search_read_range(_offset);
     size_t buf_size;
@@ -453,11 +451,14 @@ void PrefetchBuffer::prefetch_buffer() {
         buf_size = merge_small_ranges(_offset, read_range_index);
     }
 
+    _len = 0;
+    Status s;
+
     {
         SCOPED_RAW_TIMER(&_statis.read_time);
         s = _reader->read_at(_offset, Slice {_buf.get(), buf_size}, &_len, _io_ctx);
     }
-    if (UNLIKELY(buf_size != _len)) {
+    if (UNLIKELY(s.ok() && buf_size != _len)) {
         // This indicates that the data size returned by S3 object storage is smaller than what we requested,
         // which seems to be a violation of the S3 protocol since our request range was valid.
         // We currently consider this situation a bug and will treat this task as a failure.
diff --git a/be/src/io/fs/buffered_reader.h b/be/src/io/fs/buffered_reader.h
index 8e5d87fcc2..01422cacac 100644
--- a/be/src/io/fs/buffered_reader.h
+++ b/be/src/io/fs/buffered_reader.h
@@ -170,9 +170,7 @@ public:
     }
 
     ~MergeRangeFileReader() override {
-        if (_read_slice != nullptr) {
-            delete[] _read_slice;
-        }
+        delete[] _read_slice;
         for (char* box : _boxes) {
             delete[] box;
         }
@@ -289,7 +287,7 @@ struct PrefetchBuffer : std::enable_shared_from_this<PrefetchBuffer> {
               _reader(reader),
               _io_ctx(io_ctx),
               _buf(new char[buffer_size]),
-              _sync_profile(sync_profile) {}
+              _sync_profile(std::move(sync_profile)) {}
 
     PrefetchBuffer(PrefetchBuffer&& other)
             : _offset(other._offset),
@@ -391,8 +389,8 @@ public:
 
     void set_random_access_ranges(const std::vector<PrefetchRange>* random_access_ranges) {
         _random_access_ranges = random_access_ranges;
-        for (int i = 0; i < _pre_buffers.size(); i++) {
-            _pre_buffers[i]->set_random_access_ranges(random_access_ranges);
+        for (auto& _pre_buffer : _pre_buffers) {
+            _pre_buffer->set_random_access_ranges(random_access_ranges);
         }
     }