Github user zsxwing commented on a diff in the pull request:

    https://github.com/apache/spark/pull/18317#discussion_r138189593
  
    --- Diff: 
core/src/main/java/org/apache/spark/util/collection/unsafe/sort/UnsafeSorterSpillReader.java
 ---
    @@ -72,10 +72,15 @@ public UnsafeSorterSpillReader(
           bufferSizeBytes = DEFAULT_BUFFER_SIZE_BYTES;
         }
     
    +    final Double readAheadFraction =
    +        SparkEnv.get() == null ? 0.5 :
    +             
SparkEnv.get().conf().getDouble("spark.unsafe.sorter.spill.read.ahead.fraction",
 0.5);
    +
         final InputStream bs =
             new NioBufferedFileInputStream(file, (int) bufferSizeBytes);
         try {
    -      this.in = serializerManager.wrapStream(blockId, bs);
    +      this.in = new 
ReadAheadInputStream(serializerManager.wrapStream(blockId, bs),
    --- End diff --
    
    Could you add an internal conf to disable it? It will allow the user to 
disable it when the new feature causes a regression.


---

---------------------------------------------------------------------
To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org
For additional commands, e-mail: reviews-h...@spark.apache.org

Reply via email to