Thomas Hallgren <thomas(at)tada(dot)se> writes:
> Is there a difference in how the executor treat a C function and a
> function using a call handler that can cause this behavior?
Can't think of one. You'd better take a closer look at your call
handler.
gdb'ing with a watchpoint on writes to CurrentMemoryContext might be
helpful at seeing whether the context is changing unexpectedly.
regards, tom lane