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From Apache <ralph.go...@dslextreme.com>
Subject Re: Experimenting with NIO
Date Sun, 26 Feb 2017 03:12:30 GMT
I tried using a FileChannel for the FileAppender a week or so ago to see if passing the ByteBuffer
to the FileChannel would improve performance since it doesn’t have to be synchronized. I
didn’t see any improvement though and I ended up reverting it. But I might have done something
wrong.

Ralph

> On Feb 25, 2017, at 4:19 PM, Matt Sicker <boards@gmail.com> wrote:
> 
> We already use a bit of NIO (ByteBuffer for layouts and appenders/managers, MappedByteBuffer
for mmap'd files, FileLock for locking files, etc.), and I've been playing around with the
NIO API lately. I have some sample code here <https://github.com/jvz/nio-logger <https://github.com/jvz/nio-logger>>
to show some trivial use case of AsynchronousFileChannel. In Java 7, there is also AsynchronousSocketChannel
which could theoretically be used instead of adding Netty for a faster socket appender. In
that regard, I'm curious as to how useful it would be to have similar appenders as the OutputStream
ones, but instead using WritableByteChannel, GatheringByteChannel (possible parallelization
of file writing?), and the async channels (there's an AsynchronousByteChannel class, but I
think they screwed this one up as only one of the three async channel classes implements it).
> 
> Another related issue I've seen is that in a message-oriented appender (e.g., the Kafka
one), being able to stream directly to a ByteBuffer is not the right way to go about encoding
log messages into the appender. Instead, I was thinking that a pool of reusable ByteBuffers
could be used here where a ByteBuffer is borrowed on write and returned on completion (via
a CompletionHandler callback). The Kafka client uses a similar strategy for producing messages
by dynamically allocating a pool of ByteBuffers based on available memory.
> 
> Also, I don't have much experience with this, but if we had a pool of reusable ByteBuffers,
could we use direct allocation to get off-heap buffers? That seems like an interesting use
case.
> 
> -- 
> Matt Sicker <boards@gmail.com <mailto:boards@gmail.com>>


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