Hello,
We are facing a behavior where subscribers' Pending Queue Size
increases, it seems that no ACKs are dispatched and flow ratio decreases
almost to zero.
Our topology is somehow peculiar:
We have several places, each one containing multiple machines.
Each machine has a local broker with a producer and two consumers.
Each local broker has a multicast enabled (transport connector and its
network connector), and a unidirectional (no duplex) network connector
against a central broker.
One producer and one consumer are connected using the VM, while the
other consumer is connected to a central broker.
TTL for the multicast network connector is 1, while the network
connector for the central broker has a TTL of 3.
The local brokers on each machine are using Virtual Destinations, but
they are not excluding queues for the Consumers (
Consumer.*.VirtualTopic.>).
From the central broker point of view, there are lots of duplicate
messages, which may be normal and the central broker rejects them, but
the Pending Queue Size increases until flow control marks them as slow
consumers.
From the local broker point of view, pending messages to send increase
and also does the message ACK waiting queue
(MessageCountAwaitingAcknowledge).
We'd like to avoid to change the application, so we have focused on any
parameter in the central broker that may stop this behavior.
Our mitigation plan is to delete the Kaha database on a daily basis to
remove the Pending Queue and let local brokers flow their messages.
Thanks
