Is it possibile to guarantee a FIFO order of notifications with setting of @Listener(sync = false) ?

[francesco.sclano]

Hi,

I would like to know if is it possible to configure infinispan in order to guarantee a FIFO order of notifications with setting of @Listener(sync = false) ?

In my application I have only one master node able to perform put/remove operations and all other nodes able to perform only get operations.

I would like to have the same order of execution of put/remove operations for corresponding notification, even if I set sync = false in my Listener implementation.

I mean, I would like to avoid a situation such as the one that follows:

                               MASTER NODE           READ NODE

TIMESTAMP T             put data1

TIMESTAMP T+1                                          notify data1

TIMESTAMP T+2         put data2

TIMESTAMP T+3         put data3

TIMESTAMP T+4                                           notify data3

TIMESTAMP T+5                                           notify data2

Thanks

Francesco

[william.burns]

There is no way to guarantee the ordering when the listener is set to async.  If you want something like that you could have the listener be sync but then send the operation to to a single thread executor.

There are a few other points you should know as well.

1. Even with sync listeners there is no way to guarantee ordering of notifications of different keys.  The notification is sent while the lock for that key is held, so if you have different keys they are different locks.
2. What type of cache are you using?  If you are using a Distributed Cache then there is no way to guarantee all the events will go to the same node to be ordered even.  If so you should look at the new Community feature in Infinispan 7 Clustered Listeners http://blog.infinispan.org/2014/03/embedded-cluster-listeners-in.html