A few other function and state questions. When there is existing data
in a topic:
1. Does a newly-deployed function start consuming from the start of a
topic, or the end? (Or is this selectable?)
2. Can a newly-deployed function be told to consume the compacted
version of a topic?
3. Is it possible to "rewind" the subscription of a deployed function to
a previous point in time?
3b. If so, will this also reset stored state to how it was at that point
in time?
4. From the command line, can I wipe *all* the state stored for a function?
5. Can I list the stored state keys, so I can iterate over them? (Aside:
I looked in the REST API documentation, but it doesn't seem to cover
administering functions at all)
AFAICS, functions have subscription(s) to their input topic(s); indeed I
can see them in the output of "pulsar-admin topics subscriptions
<topicname>"
So for (3) I guess it's possible to use "reset-cursor" on the
subscription - but I'm not sure if that's safe/recommended with pulsar
functions. It surely wouldn't update state though (3b).
The reason for question (3b) is I wonder if it's possible to change the
logic in a function (e.g. make a logic fix) and re-run it over the last
hour/day/whatever, with the state back as it was then. That avoids
having to re-run from the beginning of time.
Thanks,
Brian.
