Tuesday, August 23, 2016

JGroups 4.0.0.Alpha1 released

Howdy folks,

I just released a first alpha of JGroups 4.0.0 to SourceForge and maven. There are 12+ issues left, and I expect a final release in October.

The major version number was incremented because there are a lot of API changes and removal of deprecated classes/methods.

I'd be happy to get feedback on the API; there's still time to make a few API changes until the final release.

Major API changes

New features 


Deliver message batches

Ability to handle message batches in addition to individual messages: receive(MessageBatch) was added to ReceiverAdapter: https://issues.jboss.org/browse/JGRP-2003

Encryption and authentication

ENCRYPT was removed and replaced by SYM_ENCRYPT (keystore-based) and ASYM_ENCRYPT (asymmetric key exchange): https://issues.jboss.org/browse/JGRP-2021.

ENCRYPT had a couple of security flaws, and since the code hasn't been touched for almost a decade, I took this chance and completely refactored it into the 2 protocols above.

The code is now much more readable and maintainable.



Removal of Java serialization

JGroups marshalling falls back to Java serialization if a class is not primitive or implements Streamable. This was completely removed for JGroups-internal classes:  https://issues.jboss.org/browse/JGRP-2033

MessageBundler improvements

The performance of existing bundlers has been improved, and new bundlers (RingBufferBundler, NoBundler) have been added. Since the shared transport feature was removed, SingletonAddress used as key into a bundler's hashmap could also be removed.

For instance, TransferQueueBundler now removes chunks of message from the queue, rather than one-by-one: https://issues.jboss.org/browse/JGRP-2076.

I also added the ability to switch bundlers at runtime (via (e.g.) probe.sh op=TCP.bundler["rb"]): https://issues.jboss.org/browse/JGRP-2057 / https://issues.jboss.org/browse/JGRP-2058

Reduction of event creation

For every message sent up or down, a new Event (wrapping the message) had to be created. Adding 2 separate up(Message) and down(Message) callbacks removed that unneeded creation: https://issues.jboss.org/browse/JGRP-2067

Faster header marshalling and creation

Headers used to do a hashmap lookup to get their magic-id when getting marshalled. Now they carry the magic ID directly in the header. This saves a hashmap lookup per header (usually we have 3-4 headers per message): https://issues.jboss.org/browse/JGRP-2042.

Header creation was getting the class using a lookup with the magic ID, and then creating an instance. This was replaced by each header class implementing a create() method, resulting in header creation getting from 300ns down to 25ns.

Bug fixes

MFC and UFC headers getting mixed up

This is a regression that led to premature exhaustion of credits, slowing things down:



The manual has not been changed yet, so browse the source code or javadocs for details.

Enjoy! and feedback via the mailing list, please!


Bela Ban

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