Say the product backlog has 90 stories and about 30 stories which make part of functionality of the application is developed and delivered during previous sprints. The PO choose to release this delivered functionality and put it in production.
Currently, I am at sprint 6 and the sprint duration is 3 weeks. The sprint has started with about 5 stories as it's sprint backlog items and by now one week of the sprint has passed.
Now the PO discovers a production bug or an important functionality that needs to be added on the production application on top priority. The estimate for this fix or functionality is just few story points that can be delivered in few hours based on teams velocity.
By now hopefully you see the situation the PO is in. Even if the development team (as only DT can modify the sprint backlog not the PO) is willing to take this fix/functionality in to there sprint backlog, the delivery of it will take another 2 weeks (as only one week of the 3 weeks of sprint has passed) and the PO can not wait that long.
What can the PO do in this situation.
1) Can he initiate another new Sprint that lasts only few hours or at most for a day (I would like to call this micro sprints). So here part of the question - Can sprints last for few hours or for a day or two at most. (from what i have read any where, the shortest sprint duration's I have read or heard is of 1 week) So I have this doubt, is it possible to have short sprints of few hours or a day and are they valid and acceptable in scrum.
2) what do you suggestion on how the PO should handle this top priority and urgent fix/functionality that needs immediate delivery.
Note: every thing on the project should be done through a formal scrum process only.