On Aug 8, 2006, at 6:18 AM, Anders Bengtsson wrote:
On a related issue, should AMQ detect message loops? Some
documentation says
that it does, by keeping a list of all visited brokers in each
message,
while other documentation (for network TTL) warns about the risk of
loops
with a high network TTL.
We experienced a few message loops when trying out some more
complex broker
network topologies.
The last I looked into this (late winter, around 4.0-M3 I think)
there were known issues with some network topologies. True loops
seemed to be detected ok, but some common non-loop multiple paths
were not detected. For example if you have a producer to broker A, A
connected to brokers B1 and B2, B1 and B2 connected only to broker C,
and you consume from C, then your consumer would see 2 copies of each
message on a topic.
Since we don't use master/slave and we needed multiple brokers on
each hop for redundancy we use queues on the paths that would give us
troubles. Queues ensure that only one path gets a message. The new
virtual destination functionality will make this kind of setup even
easier.
John
