remove another implementation detail

delivery/overview.mdx

@@ -139,13 +139,9 @@ There are two primary batching strategies:
 - **Batching based on rollover interval**:
     For batching based on the time interval, RisingWave checks the threshold each time a chunk is about to be written (`sink_writer.write_batch()`) and when a barrier is encountered (`sink_writer.barrier()`).
 
-The batching condition is relatively coarse-grained. Setting a specific number of rows for batching does not guarantee that the output file will contain exactly that many rows.
+The condition for batching is relatively coarse-grained. Setting a specific number of rows for batching does not guarantee that the output file will contain exactly that many rows.
 
-### Sink decoupling with batching strategy
-
-With the batching strategy for file sink, file writing is no longer dependent on the arrival of barriers.  `BatchingLogSinkOf` determines when to truncate the log store. Once a file is written, it will be truncated. However, if batching occurs across barriers and no writing has occurred by the time a barrier arrives, the barrier will not trigger truncation. 
-
-If no batching strategy is defined, the previous logic will still apply, meaning that a file will be forcefully written upon the arrival of a checkpoint barrier.
+If no conditions for batch collection are set, RisingWave will apply a default batching strategy to ensure proper file writing and data consistency.
 
 ### File naming rule