In my test-case I had my consumers set up with stomp (I wrote it in typescript), and used the CLIENT_INDIVIDUAL mode ( https://stomp.github.io/stomp-specification-1.2.html#SUBSCRIBE_ack_Header ). So I thought that might delay messages from a specific queue until the current one was acked, but with my consumers waiting 500ms until acking, they still received new messages from the queues immediately.
And in that test-case I also tried consumerWindowSize=0 as a query-param on the connection string, and also as a default address setting for all queues. ons. 8. jul. 2020 kl. 17:01 skrev Tim Bain <[email protected]>: > Would CLIENT_ACKNOWLEDGE (or INDIVIDUAL_ACKNOWLEDGE, though I don't think > it buys you anything over CLIENT_ACKNOWLEDGE) delivery modes address your > use case, by allowing your clients control over when messages are acked? > > Tim > > On Wed, Jul 8, 2020, 5:57 AM Domenico Francesco Bruscino < > [email protected]> wrote: > > > Hi Kristinn, > > > > the prefetch limit is for consumers and the current implementation of the > > activemq-client 5 automatically sends a delivery acknowledgement when the > > unacknowledged messages are more than the half of the prefetch limit, so > I > > don't think it can help. > > > > Regards, > > Domenico > > > > Il giorno mar 7 lug 2020 alle ore 10:11 Kristinn Thor Johannsson < > > [email protected]> ha scritto: > > > > > The use case can be explained like this: > > > > > > We are doing some work based on git commits, and for each target > (either > > > commit or user defined branch name) we only want to be handling the > first > > > workload before starting the next. > > > So we're probably going to have a high number of topics (each unique > > > commit), but within each of those topics there might only be 1-3 > messages > > > to be handled (with the exception of the user defined branch named > > > targets). > > > > > > So we were thinking that a mq might be able to help us do this in a > > > performant way, where our consumers are only informed of messages that > > are > > > ready and valid to start (no active workload for that specific > > > commit/branch name and it's the next within that topic). > > > > > > I've read the doc page you linked to about prefetch limit, could I use > > the > > > prefetch limit set to 1 for topics to achieve this? > > > > > > man. 6. jul. 2020 kl. 18:14 skrev Domenico Francesco Bruscino < > > > [email protected]>: > > > > > > > Hi Kristinn, > > > > > > > > the acknowledgements confirm the successful consumption of a message > to > > > the > > > > server and generally it doesn't control directly the flow of data > > between > > > > the server and the client[1]. > > > > > > > > Using the messaging group suitably, only one consumer will receive > the > > > > messages of a queue and if your consumer is slow you could > > > > set consumerWindowSize to 0 (for no buffer at all)[2] to limit the > > > > redeliveries on disconnection. > > > > So using the messaging group and setting consumerWindowSize to 0, the > > > > server sends all the messages of a queue to one consumer and the > > consumer > > > > doesn't receive the next message before invoking the `receive()` > method > > > or > > > > asynchronously via a message listener. > > > > > > > > If this solution doesn't match your requirements, the > activemq-client 5 > > > > offers a way to control the delivery with the acknowledgements using > > > > prefetch limit [3]. > > > > Why do you need to lock the delivery of the next message until > > > > the acknowledgement of the previous one? > > > > > > > > [1] > > > > > > > > > > > > > > https://activemq.apache.org/components/artemis/documentation/latest/flow-control.html > > > > [2] > > > > > > > > > > > > > > https://activemq.apache.org/components/artemis/documentation/latest/flow-control.html#slow-consumers > > > > [3] https://activemq.apache.org/what-is-the-prefetch-limit-for > > > > > > > > Regards, > > > > Domenico > > > > > > > > Il giorno lun 6 lug 2020 alle ore 09:50 Kristinn Thor Johannsson < > > > > [email protected]> ha scritto: > > > > > > > > > Thanks a lot for the response Domenico. > > > > > > > > > > I see what I failed to mention in my original question is that each > > > > > consumer might need a while to process a message from each queue > it's > > > > > handling. > > > > > In your example, you had auto-acknowledge, making each message > being > > > > > instantly handled by the consumer. > > > > > > > > > > Is your example modifiable to make it so that a message takes > about 1 > > > > > second to be handled and acknowledged, and the consumer doesn't > > receive > > > > the > > > > > next message for the same queue before that happens? > > > > > If so, I'm certain our use case can be handled by artemis. > > > > > > > > > > > > > > > fre. 3. jul. 2020 kl. 13:02 skrev Domenico Francesco Bruscino < > > > > > [email protected]>: > > > > > > > > > > > Hi Kristinn, > > > > > > > > > > > > I have just answered the same question on stackoverflow: > > > > > > > > > > > > > > > > > > > > > > > > > > > https://stackoverflow.com/questions/62701025/activemq-artemis-handle-messages-sequentially/62705413#62705413 > > > > > > > > > > > > Regards, > > > > > > Domenico > > > > > > > > > > > > Il giorno gio 18 giu 2020 alle ore 10:51 Kristinn Thor > Johannsson < > > > > > > [email protected]> ha scritto: > > > > > > > > > > > > > Hi, I've tried to ensure that a consumer on a queue (with > message > > > > > > grouping) > > > > > > > will only receive one message at a time from each queue it's > > > > handling, > > > > > > > until the consumer acknowledges said message. > > > > > > > > > > > > > > For a test I've set up ActiveMQ Artemis and have 3 consumers > on a > > > > > > wildcard > > > > > > > EXAMPLE.* , and one publisher posting 10 messages to each of 5 > > > > queues: > > > > > > > EXAMPLE.1 - EXAMPLE.5 . What I'm seeing is that each of the > > > consumers > > > > > > > receive messages from the queues immediately. I've tried using > > the > > > > > > consumer > > > > > > > window size setting (as 0) as I thought that would help me only > > > > deliver > > > > > > one > > > > > > > message at a time from each queue, but that doesn't seem to > work. > > > > Have > > > > > I > > > > > > > misunderstood that setting? If so, are there any other > settings I > > > > > should > > > > > > be > > > > > > > looking at to help me get this working? > > > > > > > > > > > > > > The particular use case I'm trying to achieve is that I'll > > possibly > > > > > have > > > > > > > many queues and a couple of consumers. And it's important that > > > > messages > > > > > > in > > > > > > > each of the queues are handled sequentially, but all queues can > > be > > > > > > handled > > > > > > > in parallell > > > > > > > > > > > > > > -- > > > > > > > -Kristinn Thor > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > > -Kristinn Thor > > > > > > > > > > > > > > > > > > -- > > > -Kristinn Thor > > > > > > -- -Kristinn Thor
