+1
Penghui On Jul 28, 2022, 20:14 +0800, lordcheng10 <1572139...@qq.com.invalid>, wrote: > Nice feature! > > > > > ------------------ Original ------------------ > From: "Yunze Xu"<y...@streamnative.io.INVALID>; > Date: 2022Äê7ÔÂ15ÈÕ(ÐÇÆÚÎå) ÍíÉÏ6:04 > To: "dev"<dev@pulsar.apache.org>; > Subject: [DISCUSS] User-friendly acknowledgeCumulative API on a partitioned > topic or multi-topics > > > > Hi all, > > Long days ago I opened a PR to support cumulative acknowledgement > for C++ client, but it's controversial about whether should a > partitioned consumer acknowledge a message ID cumulatively. > > See https://github.com/apache/pulsar/pull/6796 for discussion. > > Currently, the Java client acknowledges the specific partition of the > message ID, while the C++ client just fails when calling > `acknowledgeCumulative` on a partitioned topic. However, even if the > Java client doesn't fail, it's not user friendly. > > Assuming users called `acknowledgeCumulative` periodically, there is a > chance that some messages of the specific partition has never been > passed to the method. > > For example, a consumer received: > > P0-M0, P1-M0, P0-M1, P1-M1, P0-M2, P1-M2... > > And the user acknowledged every two messages, i.e. > > P0-M0, P0-M1, P0-M2 > > Eventually, partition 1 has never been acknowledged. > > User must maintain its own `Map<String, MessageId>` cache for a > partitioned topic or multi-topics consumer with the existing > `acknowledgeCumulative` API. > > Should we make it more friendly for users? For example, we can make > `acknowledgeCumulative` accept the map to remind users to maintain > the map from topic name to message ID: > > ```java > // the key is the partitioned topic name like my-topic-partition-0 > void acknowledgeCumulative(Map<String, MessageId> topicToMessageId); > ``` > > For those who don't want to maintain the map by themselves, maybe we > can provide a simpler API like: > > ```java > // acknowlegde all latest received messages > void acknowledgeCumulative(); > ``` > > and provide an option to enable this behavior. > > Do you have any suggestion on this idea? I will prepare a proposal if > there is no disagreement. > > Thanks, > Yunze
