- Implement “semantic” slicing for datatypes that support slicing into TOAST tables. These datatypes will be the Text, Array, JSON/JSONb and XML data types.
That looks too much comprehensive GSoC project for me. I would recommend you to focus on more local task. For instance, providing better slicing for jsonb with support of all relevant functions/operators looks pretty enough work amount for GSoC project.
Remember, that the major target of GSoC project is to get it complete. I.e. to produce patch in committable shape, not just a prototype. That's quite ambitious, because this project also assumes some research. Thus, there could be various approaches for slicing jsonb with different advantages and disadvantages. So, I advice you to thought out approaches you're going to try, and specify them in proposal. Schedule should include prototyping each of these approaches, then testing and benchmarking to selecting between them, then work on bringing selected approach to committable shape.
