[
https://issues.apache.org/jira/browse/DIRMINA-845?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13072932#comment-13072932
]
Emmanuel Lecharny commented on DIRMINA-845:
-------------------------------------------
Still puzzled...
If the chunks are written in the CLQ in the right order, there is no reason for
those chunks to be send in another order, as the queue is read sequentially in
the flush() method.
The only reason you might send those message in the wrong order is that they
are read from the queue by two different threads, which should not be the
case...
Am I missing something ?
> ProtocolEncoderOutputImpl isn't thread-safe
> -------------------------------------------
>
> Key: DIRMINA-845
> URL: https://issues.apache.org/jira/browse/DIRMINA-845
> Project: MINA
> Issue Type: Bug
> Components: Filter
> Affects Versions: 2.0.4
> Reporter: Ilya Ivanov
>
> ProtocolEncoderOutputImpl uses ConcurrentLinkedQueue and at first look it
> seems to be thread-safe. But really concurrent execution of flush method
> isn't thread-safe (and write-mergeAll also).
> E.g. in RTMP several channels multiplexed in single connection. According
> protocol specification it's possible to write to different channels
> concurrently. But it doesn't work with MINA.
> I've synchronized channel writing, but it doesn't prevent concurrent run of
> flushing (in 2.0.4 it's done directly in ProtocolCodecFilter.filterWrite, but
> ProtocolEncoderOutputImpl.flush has the same problem).
> Here the fragment of flushing code:
> while (!bufferQueue.isEmpty()) {
> Object encodedMessage = bufferQueue.poll();
>
> if (encodedMessage == null) {
> break;
> }
> // Flush only when the buffer has remaining.
> if (!(encodedMessage instanceof IoBuffer) || ((IoBuffer)
> encodedMessage).hasRemaining()) {
> SocketAddress destination = writeRequest.getDestination();
> WriteRequest encodedWriteRequest = new
> EncodedWriteRequest(encodedMessage, null, destination);
> nextFilter.filterWrite(session, encodedWriteRequest);
> }
> }
> Suppose original packets sequence is A, B, ...
> Concurrent run of flushing may proceed as following:
> thread-1: Object encodedMessage = bufferQueue.poll(); // gets A packet
> thread-2: Object encodedMessage = bufferQueue.poll(); // gets B packet
> ...
> thread-2: nextFilter.filterWrite(...); // writes B packet
> thread-1: nextFilter.filterWrite(...); // writes A packet
> so, resulting sequence will B, A
> It's quite confusing result especially when documentation doesn't contain any
> explanation about such behavior.
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
