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https://issues.apache.org/jira/browse/FLINK-11775?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16798922#comment-16798922
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Piotr Nowojski commented on FLINK-11775:
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Sorry for asking maybe stupid question, I'm not very familiar with this code.
Shouldn't we in that case try to optimize the
{{HybridMemorySegment#put(java.io.DataInput, int, int)}} for off heap cases.
For example for cases when {{DataInput}} is backed by array or something that
can be easily wrapped as ByteBuffer or something else that's efficient? Like:
{code:java}
@Override
public final void put(DataInput in, int offset, int length) throws
IOException {
if (address <= addressLimit) {
if (heapMemory != null) {
in.readFully(heapMemory, offset, length);
}
else {
ByteBuffer src = in.wrapAsByteBuffer();
offHeapBuffer.put(src);
}
}
else {
throw new IllegalStateException("segment has been
freed");
}
}
{code}
and provide some efficient implementation of {{wrapAsByteBuffer()}} for
{{DataInputView}} that are wrapping {{MemorySegment}}?
> Introduce MemorySegmentWritable to let DataOutputView direct copy to internal
> bytes
> -----------------------------------------------------------------------------------
>
> Key: FLINK-11775
> URL: https://issues.apache.org/jira/browse/FLINK-11775
> Project: Flink
> Issue Type: New Feature
> Components: Runtime / Operators
> Reporter: Jingsong Lee
> Assignee: Jingsong Lee
> Priority: Major
>
> Blink new binary format is based on MemorySegment.
> Introduce MemorySegmentWritable to let DataOutputView direct copy to internal
> bytes
> {code:java}
> /**
> * Provides the interface for write(Segment).
> */
> public interface MemorySegmentWritable {
> /**
> * Writes {@code len} bytes from memory segment {@code segment} starting at
> offset {@code off}, in order,
> * to the output.
> *
> * @param segment memory segment to copy the bytes from.
> * @param off the start offset in the memory segment.
> * @param len The number of bytes to copy.
> * @throws IOException if an I/O error occurs.
> */
> void write(MemorySegment segment, int off, int len) throws IOException;
> }{code}
>
> If we want to write a Memory Segment to DataOutputView, we need to copy bytes
> to byte[] and then write it in, which is less effective.
> If we let AbstractPagedOutputView have a write(MemorySegment) interface, we
> can copy it directly.
> We need to ensure this in network serialization, batch operator calculation
> serialization, Streaming State serialization to avoid new byte[] and copy.
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