Pending Queue Size does not flush

[Andreas Calvo Gómez <an...@scytl.com>]

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