Hi Asanka, +1. Seems we need to consider all clients w:r:t a queue. In previous model also we had a property to count number of times a message was delivered and a delivery rule to evaluate but it was channel-wise (per subscriber).
So if a queue or a shared durable topic subscriber has more than one subscriber, we should consider deliveries to all consumers of that queue/internal queue of durable topic subscriber. Let us go with that approach. Thanks On Fri, Jan 12, 2018 at 10:55 AM, Asanka Abeyweera <asank...@wso2.com> wrote: > In the previous MB versions, we were counting the redelivery count > independently for each consumer. But according to the spec, this is counted > independently of the delivered consumer. > > The server SHOULD track the number of times a message has been delivered >> to *clients* and when a message is redelivered a certain number of times >> e.g. 5 times without being acknowledged, the server SHOULD consider the >> message to be unprocessable (possibly causing client applications to >> abort), and move the message to a dead letter queue. >> > > Therefore we are planning to keep the redelivery count independent of the > consumer and publish the message to DLX when the count exceeds the > configured limit. > > > On Fri, Jan 12, 2018 at 10:15 AM, Asanka Abeyweera <asank...@wso2.com> > wrote: > >> Hi all, >> >> For message brokers, we need to provide a location to dump undeliverable >> messages. Messages can be undeliverable due to following reasons. >> >> 1. Message redelivery count exceeds a configured limit. >> 2. The queue length limit is exceeded. >> >> In previous versions of MB, we were using a dedicated queue (DLC) to >> persist those undeliverable messages. This was adding some complexity in >> handling permission and different policies with DLC. In MB4 we are planning >> to implement a Dead Letter Exchange (DLX) instead. >> In the first iteration of the implementation, we planning to have an >> inbuilt DLX which is used to publish undeliverable messages. Type of the >> DLX is of type direct. We will also create a default dead letter queue and >> have a binding added to the DLX for the default dead letter queue. This >> will be the default path of any undeliverable message. >> >> In a later iteration, we can add the capability to define custom queues >> and exchanges for routing undeliverable messages. This will make it easy ti >> define different policies for different dead letter scenarios. >> >> WDYT? >> -- >> Asanka Abeyweera >> Associate Technical Lead >> WSO2 Inc. >> >> Phone: +94 712228648 <+94%2071%20222%208648> >> Blog: a5anka.github.io >> >> <https://wso2.com/signature> >> > > > > -- > Asanka Abeyweera > Associate Technical Lead > WSO2 Inc. > > Phone: +94 712228648 > Blog: a5anka.github.io > > <https://wso2.com/signature> > -- *Hasitha Abeykoon* Associate Technical Lead; WSO2, Inc.; http://wso2.com *cell:* *+94 719363063* *blog: **abeykoon.blogspot.com* <http://abeykoon.blogspot.com>
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