MAPREDUCE-6678. Allow ShuffleHandler readahead without drop-behind. Contributed by Nathan Roberts.

(cherry picked from commit cd35b692de88e3afe7f41405da635c3fbd9b4650)
This commit is contained in:
Eric Payne 2016-05-10 15:45:01 +00:00
parent e0d6a9632d
commit 77d147e0ec

View File

@ -74,7 +74,7 @@ public FadvisedFileRegion(RandomAccessFile file, long position, long count,
@Override @Override
public long transferTo(WritableByteChannel target, long position) public long transferTo(WritableByteChannel target, long position)
throws IOException { throws IOException {
if (manageOsCache && readaheadPool != null) { if (readaheadPool != null && readaheadLength > 0) {
readaheadRequest = readaheadPool.readaheadStream(identifier, fd, readaheadRequest = readaheadPool.readaheadStream(identifier, fd,
getPosition() + position, readaheadLength, getPosition() + position, readaheadLength,
getPosition() + getCount(), readaheadRequest); getPosition() + getCount(), readaheadRequest);