> * Do we need to disable sort-path for tables clustered on a gist index?
Yes; as I said in a previous mail, only plain btree indexes (that is, not
custom expression indexes) would have that option (at least in a first
version...)
> * I'd prefer to separate cost calculation routines from create_index_path()
> and cost_sort(), rather than using a dummy planner.
How? Copy&paste (removing unnecessary code) of the existing
create_index_path() and cost_sort()?
Leonardo