For example, when users create a regex consumer that subscribes to
topics ("tp0", "tp1", ..., "tpN") and seek to the earliest, they might
expect to consume messages from these topics. However, if they used a
wrong regex like "tp*" (it should be "tp.*), then they might find no
messages are available even if they're sure there is at least one
non-empty topic whose name starts at "tp" from the topic stats.Thanks, Yunze On Wed, May 29, 2024 at 7:32 PM Enrico Olivelli <eolive...@gmail.com> wrote: > > Il giorno mer 29 mag 2024 alle ore 11:10 Baodi Shi <ba...@apache.org> ha > scritto: > > > +1 > > > > > > Thanks, > > Baodi Shi > > > > > > On May 29, 2024 at 14:50:12, Yunze Xu <x...@apache.org> wrote: > > > > > Hi community, > > > > > > Recently I found the behavior of seeking a multi-topics consumer is > > > intuitive. If there are no internal consumers, the `seek` call will > > > just succeed silently. > > > > > > > > > > If a consumer subscribes with a regex and no topics are found, users > > > might think the seek operation succeeds while no topics are sought. > > > > > > I suggest throwing an exception in this case to notify users that the > > > consumer to seek is a multi-topics consumer that contains no topics. > > > It's a breaking change so I'd like to hear more voices in the mail > > > > What happens if it subscribed to a regex which "currently" doesn't not > match any topics ? > Maybe this is intentional in the application design as maybe you have > dynamic topics > > Giving an error or failing silently doesn't fix the problem. > If the application is sure that you must have at least N topics then we > should make this configurable somewhere. > The difference between "zero topics" or "one topic" is very small, if your > application expects to subscribe to 100 topics. > > > Enrico > > > > > > list. > > > > > > For now, I report an error for the C++ client [1], which might also > > > affect the Python and Node.js clients. But the behavior of the Java > > > client does not change. > > > > > > [1] https://github.com/apache/pulsar-client-cpp/pull/426 > > > > > > Thanks, > > > Yunze > > > > >
