I have created a FDW for a storage backend and it is working well, and now I would like to overlap processing with I/O by performing read-ahead. I started by using a thread to do background I/O and this worked, but problems started to arise when I tried to do predicate filtering in the thread.
In particular, it seems as though `check_stack_depth` is built to assume a single threaded environment (`stack_base_ptr` is global).
I'm wondering if there is a solution to this problem, or if there are examples of overlapping tuple I/O and predicate filtering using non-multithreading techniques?
