ankuriitg commented on a change in pull request #23453: [SPARK-26089][CORE]
Handle corruption in large shuffle blocks
URL: https://github.com/apache/spark/pull/23453#discussion_r264317097
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File path:
core/src/main/scala/org/apache/spark/storage/ShuffleBlockFetcherIterator.scala
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@@ -466,16 +469,19 @@ final class ShuffleBlockFetcherIterator(
var isStreamCopied: Boolean = false
try {
input = streamWrapper(blockId, in)
- // Only copy the stream if it's wrapped by compression or
encryption, also the size of
- // block is small (the decompressed block is smaller than
maxBytesInFlight)
- if (detectCorrupt && !input.eq(in) && size < maxBytesInFlight / 3)
{
+ // Only copy the stream if it's wrapped by compression or
encryption upto a size of
+ // maxBytesInFlight/3. If stream is longer, then corruption will
be caught while reading
+ // the stream.
+ streamCompressedOrEncrypted = !input.eq(in)
+ if (streamCompressedOrEncrypted && detectCorruptUseExtraMemory) {
isStreamCopied = true
- val out = new ChunkedByteBufferOutputStream(64 * 1024,
ByteBuffer.allocate)
- // Decompress the whole block at once to detect any corruption,
which could increase
- // the memory usage tne potential increase the chance of OOM.
+ // Decompress the block upto maxBytesInFlight/3 at once to
detect any corruption which
+ // could increase the memory usage and potentially increase the
chance of OOM.
// TODO: manage the memory used here, and spill it into disk in
case of OOM.
- Utils.copyStream(input, out, closeStreams = true)
- input = out.toChunkedByteBuffer.toInputStream(dispose = true)
+ val (fullyCopied: Boolean, mergedStream: InputStream) =
Utils.copyStreamUpTo(
+ input, maxBytesInFlight / 3)
Review comment:
I think in.close() is needed if there is an exception while creating a
wrapped stream. The first time I saw `isStreamCopied`, I was also confused and
by looking at it more closely now, I realize that it is not doing what it is
supposed to do.
I have removed `isStreamCopied` and instead used another condition to close
the stream. Please check and let me know if it makes sense.
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