mridulm commented on a change in pull request #32287:
URL: https://github.com/apache/spark/pull/32287#discussion_r618106484
##########
File path:
core/src/main/scala/org/apache/spark/storage/ShuffleBlockFetcherIterator.scala
##########
@@ -683,7 +694,28 @@ final class ShuffleBlockFetcherIterator(
}
}
- case FailureFetchResult(blockId, mapIndex, address, e) =>
+ // Catching OOM and do something based on it is only a workaround for
handling the
+ // Netty OOM issue, which is not the best way towards memory
management. We can
+ // get rid of it when we find a way to manage Netty's memory precisely.
+ case FailureFetchResult(blockId, mapIndex, address, size,
isNetworkReqDone, e)
+ if e.isInstanceOf[OutOfDirectMemoryError] ||
e.isInstanceOf[NettyOutOfMemoryError] =>
+ assert(address != blockManager.blockManagerId &&
+ !hostLocalBlocks.contains(blockId -> mapIndex),
+ "Netty OOM error should only happen on remote fetch requests")
+ logWarning(s"Failed to fetch block $blockId due to Netty OOM, will
retry", e)
+ NettyUtils.isNettyOOMOnShuffle = true
+ numBlocksInFlightPerAddress(address) =
numBlocksInFlightPerAddress(address) - 1
+ bytesInFlight -= size
+ if (isNetworkReqDone) {
+ reqsInFlight -= 1
+ logDebug("Number of requests in flight " + reqsInFlight)
+ }
+ val defReqQueue =
+ deferredFetchRequests.getOrElseUpdate(address, new
Queue[FetchRequest]())
+ defReqQueue.enqueue(FetchRequest(address,
Array(FetchBlockInfo(blockId, size, mapIndex))))
Review comment:
How many times will we retry ?
##########
File path:
common/network-common/src/main/java/org/apache/spark/network/util/NettyUtils.java
##########
@@ -37,6 +37,14 @@
*/
public class NettyUtils {
+ /**
+ * A flag which indicates whether the Netty OOM error has raised during
shuffle.
+ * If true, unless there's no in-flight fetch requests, all the pending
shuffle
+ * fetch requests will be deferred until the flag is unset (whenever there's
a
+ * complete fetch request).
+ */
+ public static volatile boolean isNettyOOMOnShuffle = false;
Review comment:
super nit: Make it `AtomicBoolean` instead ?
##########
File path:
core/src/main/scala/org/apache/spark/storage/ShuffleBlockFetcherIterator.scala
##########
@@ -801,6 +838,8 @@ private class BufferReleasingInputStream(
if (!closed) {
delegate.close()
iterator.releaseCurrentResultBuffer()
+ // Unset the flag when a remote request finished.
+ if (isNetworkReqDone) NettyUtils.isNettyOOMOnShuffle = false
closed = true
Review comment:
Move this intro try/finally ? close exceptions can get ignored; while
`isNettyOOMOnShuffle` will never get unset
##########
File path:
common/network-common/src/main/java/org/apache/spark/network/util/NettyOutOfMemoryError.java
##########
@@ -0,0 +1,26 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.network.util;
+
+/**
+ * This class is for test only. It's needed because neither the constructor of
Netty's
+ * {@link io.netty.util.internal.OutOfDirectMemoryError} can be accessed nor
be mocked
+ * due to the type is declared as final.
+ */
+public class NettyOutOfMemoryError extends OutOfMemoryError {
Review comment:
Nit: Rename to make it clear this is just for test ?
Thought: Can we use `SparkOutOfMemoryError` instead ? We can move it out to
a module accessible from here as well ?
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