attilapiros commented on a change in pull request #23602:
[SPARK-26674][CORE]Consolidate CompositeByteBuf when reading large frame
URL: https://github.com/apache/spark/pull/23602#discussion_r257186965
##########
File path:
common/network-common/src/main/java/org/apache/spark/network/util/TransportFrameDecoder.java
##########
@@ -123,30 +140,54 @@ private long decodeFrameSize() {
private ByteBuf decodeNext() {
long frameSize = decodeFrameSize();
- if (frameSize == UNKNOWN_FRAME_SIZE || totalSize < frameSize) {
+ if (frameSize == UNKNOWN_FRAME_SIZE) {
return null;
}
- // Reset size for next frame.
- nextFrameSize = UNKNOWN_FRAME_SIZE;
-
- Preconditions.checkArgument(frameSize < MAX_FRAME_SIZE, "Too large frame:
%s", frameSize);
- Preconditions.checkArgument(frameSize > 0, "Frame length should be
positive: %s", frameSize);
+ if (frameBuf == null) {
+ Preconditions.checkArgument(frameSize < MAX_FRAME_SIZE,
+ "Too large frame: %s", frameSize);
+ Preconditions.checkArgument(frameSize > 0,
+ "Frame length should be positive: %s", frameSize);
+ frameRemainingBytes = (int) frameSize;
- // If the first buffer holds the entire frame, return it.
- int remaining = (int) frameSize;
- if (buffers.getFirst().readableBytes() >= remaining) {
- return nextBufferForFrame(remaining);
+ // If buffers is empty, then return immediately for more input data.
+ if (buffers.isEmpty()) {
+ return null;
+ }
+ // Otherwise, if the first buffer holds the entire frame, we attempt to
+ // build frame with it and return.
+ if (buffers.getFirst().readableBytes() >= frameRemainingBytes) {
+ // Reset buf and size for next frame.
+ frameBuf = null;
+ nextFrameSize = UNKNOWN_FRAME_SIZE;
+ return nextBufferForFrame(frameRemainingBytes);
+ }
+ // Other cases, create a composite buffer to manage all the buffers.
+ frameBuf = buffers.getFirst().alloc().compositeBuffer(Integer.MAX_VALUE);
}
- // Otherwise, create a composite buffer.
- CompositeByteBuf frame =
buffers.getFirst().alloc().compositeBuffer(Integer.MAX_VALUE);
- while (remaining > 0) {
- ByteBuf next = nextBufferForFrame(remaining);
- remaining -= next.readableBytes();
- frame.addComponent(next).writerIndex(frame.writerIndex() +
next.readableBytes());
+ while (frameRemainingBytes > 0 && !buffers.isEmpty()) {
+ ByteBuf next = nextBufferForFrame(frameRemainingBytes);
+ frameRemainingBytes -= next.readableBytes();
+ frameBuf.addComponent(true, next);
}
- assert remaining == 0;
+ // If the delta size of frameBuf exceeds the threshold, then we do
consolidation
+ // to reduce memory consumption.
+ if (frameBuf.capacity() - consolidatedFrameBufSize > consolidateThreshold)
{
+ int newNumComponents = frameBuf.numComponents() -
consolidatedNumComponents;
+ frameBuf.consolidate(consolidatedNumComponents, newNumComponents);
+ consolidatedFrameBufSize = frameBuf.capacity();
+ consolidatedNumComponents = frameBuf.numComponents();
+ }
+ if (frameRemainingBytes > 0) {
+ return null;
+ }
+
+ // Reset buf and size for next frame.
+ ByteBuf frame = frameBuf;
+ frameBuf = null;
+ nextFrameSize = UNKNOWN_FRAME_SIZE;
Review comment:
You have to reset `consolidatedFrameBufSize` and `consolidatedNumComponents`
back to 0 for the next frame buffer.
Otherwise after a very huge frame all the smaller but still quite huge
frames are not consolidated at all.
And when consolidation starts as a frame which bigger then the maximum up to
this then only the components are consolidated which are after the previous
maximum.
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