diff --git a/core/mvcc/persistent_storage/logical_log.rs b/core/mvcc/persistent_storage/logical_log.rs
index 0bd2ad6e3..0f2cf3fc2 100644
--- a/core/mvcc/persistent_storage/logical_log.rs
+++ b/core/mvcc/persistent_storage/logical_log.rs
@@ -48,8 +48,9 @@ impl LogicalLog {
                 );
             }
         });
+        let buffer_len = buffer.len();
         let c = self.file.pwrite(self.offset, buffer, c)?;
-        self.offset += buffer.len() as u64;
+        self.offset += buffer_len as u64;
         Ok(IOResult::IO(IOCompletions::Single(c)))
     }