[SPARK-23524] Big local shuffle blocks should not be checked for corruption.

core/src/main/scala/org/apache/spark/storage/ShuffleBlockFetcherIterator.scala

@@ -90,7 +90,7 @@ final class ShuffleBlockFetcherIterator(
   private[this] val startTime = System.currentTimeMillis
 
   /** Local blocks to fetch, excluding zero-sized blocks. */
-  private[this] val localBlocks = new ArrayBuffer[BlockId]()
+  private[this] val localBlocks = scala.collection.mutable.LinkedHashSet[BlockId]()
 
   /** Remote blocks to fetch, excluding zero-sized blocks. */
   private[this] val remoteBlocks = new HashSet[BlockId]()
@@ -316,6 +316,7 @@ final class ShuffleBlockFetcherIterator(
    * track in-memory are the ManagedBuffer references themselves.
    */
   private[this] def fetchLocalBlocks() {
+    logDebug(s"Start fetching local blocks: ${localBlocks.mkString(", ")}")
     val iter = localBlocks.iterator
     while (iter.hasNext) {
       val blockId = iter.next()
@@ -324,7 +325,8 @@ final class ShuffleBlockFetcherIterator(
         shuffleMetrics.incLocalBlocksFetched(1)
         shuffleMetrics.incLocalBytesRead(buf.size)
         buf.retain()
-        results.put(new SuccessFetchResult(blockId, blockManager.blockManagerId, 0, buf, false))
+        results.put(new SuccessFetchResult(blockId, blockManager.blockManagerId,
+          buf.size(), buf, false))
       } catch {
         case e: Exception =>
           // If we see an exception, stop immediately.
@@ -397,7 +399,9 @@ final class ShuffleBlockFetcherIterator(
             }
             shuffleMetrics.incRemoteBlocksFetched(1)
           }
-          bytesInFlight -= size
+          if (!localBlocks.contains(blockId)) {
+            bytesInFlight -= size
+          }
           if (isNetworkReqDone) {
             reqsInFlight -= 1
             logDebug("Number of requests in flight " + reqsInFlight)
@@ -583,8 +587,8 @@ object ShuffleBlockFetcherIterator {
    * Result of a fetch from a remote block successfully.
    * @param blockId block id
    * @param address BlockManager that the block was fetched from.
-   * @param size estimated size of the block, used to calculate bytesInFlight.
-   *             Note that this is NOT the exact bytes.
+   * @param size estimated size of the block. Note that this is NOT the exact bytes.
+   *             Size of remote block is used to calculate bytesInFlight.
    * @param buf `ManagedBuffer` for the content.
    * @param isNetworkReqDone Is this the last network request for this host in this fetch request.
    */

core/src/test/scala/org/apache/spark/storage/ShuffleBlockFetcherIteratorSuite.scala

@@ -352,6 +352,51 @@ class ShuffleBlockFetcherIteratorSuite extends SparkFunSuite with PrivateMethodT
     intercept[FetchFailedException] { iterator.next() }
   }
 
+  test("big blocks are not checked for corruption") {
+    val corruptStream = mock(classOf[InputStream])
+    when(corruptStream.read(any(), any(), any())).thenThrow(new IOException("corrupt"))
+    val corruptBuffer = mock(classOf[ManagedBuffer])
+    when(corruptBuffer.createInputStream()).thenReturn(corruptStream)
+    doReturn(10000L).when(corruptBuffer).size()
+
+    val blockManager = mock(classOf[BlockManager])
+    val localBmId = BlockManagerId("test-client", "test-client", 1)
+    doReturn(localBmId).when(blockManager).blockManagerId
+    doReturn(corruptBuffer).when(blockManager).getBlockData(ShuffleBlockId(0, 0, 0))
+    val localBlockLengths = Seq[Tuple2[BlockId, Long]](
+      ShuffleBlockId(0, 0, 0) -> corruptBuffer.size()
+    )
+
+    val remoteBmId = BlockManagerId("test-client-1", "test-client-1", 2)
+    val remoteBlockLengths = Seq[Tuple2[BlockId, Long]](
+      ShuffleBlockId(0, 1, 0) -> corruptBuffer.size()
+    )
+
+    val transfer = createMockTransfer(
+      Map(ShuffleBlockId(0, 0, 0) -> corruptBuffer, ShuffleBlockId(0, 1, 0) -> corruptBuffer))
+
+    val blocksByAddress = Seq[(BlockManagerId, Seq[(BlockId, Long)])](
+      (localBmId, localBlockLengths),
+      (remoteBmId, remoteBlockLengths)
+    )
+
+    val taskContext = TaskContext.empty()
+    val iterator = new ShuffleBlockFetcherIterator(
+      taskContext,
+      transfer,
+      blockManager,
+      blocksByAddress,
+      (_, in) => new LimitedInputStream(in, 10000),
+      2048,
+      Int.MaxValue,
+      Int.MaxValue,
+      Int.MaxValue,
+      true)
+    // Blocks should be returned without exceptions.
+    assert(Set(iterator.next()._1, iterator.next()._1) ===
+        Set(ShuffleBlockId(0, 0, 0), ShuffleBlockId(0, 1, 0)))
+  }
+
   test("retry corrupt blocks (disabled)") {
     val blockManager = mock(classOf[BlockManager])
     val localBmId = BlockManagerId("test-client", "test-client", 1)