I have considered this issue, but it may increase the user's consumption delay. However, it is not appropriate to make modifications in the ack timeout. Yubiao and I have just discussed this issue, and we should handle it in the AcknowledgementsGroupingTracker to automatically retry failed ack requests.
Thanks, On Wed, Mar 27, 2024 at 5:37 PM ZhangJian He <shoot...@gmail.com> wrote: > > Hi, Xiangying. Have you ever considered the `isAckReceiptEnabled` param? > > Thanks > ZhangJian He > > > On Wed, Mar 27, 2024 at 3:33 PM Xiangying Meng <xiangy...@apache.org> wrote: > > > Dear Pulsar Community, > > > > I would like to initiate a discussion regarding the optimization of > > the acktimeout mechanism on the client side. As we all know, the > > Pulsar consumer has a configuration for ack timeout that automatically > > redelivers unacknowledged messages after a certain period. The > > workflow is approximately as follows: > > > > 1. Record a message when it is received. > > 2. Remove the message from the record when the consumer begins to > > acknowledge it. > > 3. A timed task checks whether the messages from the record have > > reached the ack timeout and triggers redelivery for those messages. > > > > This workflow has a potential shortcoming: it does not wait for the > > ack response before removing the message from the record. If an ack > > request is lost during transmission to the broker - due to issues with > > proxy processing or buffer overflow after reaching the broker, for > > instance - then the ack timeout will not be resent, leading to an ack > > hole. While this situation is quite extreme and the likelihood of > > occurrence is extremely low, it is nonetheless a possibility. Another, > > more common scenario is when the broker fails to process or persist > > the ack request. > > > > In such cases, users who are highly sensitive to ack holes may prefer > > the message to be removed only after receiving the ack response. > > Perhaps we could add a parameter to the acktimeout to determine > > whether to wait for the ack response before removing the message. > > > > I am interested in hearing your thoughts on this issue and look > > forward to your responses and valuable suggestions. > > > > Best Regards, > > Xiangying > >
