Basil Bourque <basil(dot)list(at)me(dot)com> writes:
> When a trigger calls a function, that function can determine if it is being called from within a trigger by testing for a value in the special variable "TG_OP".
Uh, no, not really. TG_OP is a local variable in the trigger function;
it's not visible from elsewhere.
> But what if a trigger calls a function that calls a 2nd function via the "PERFORM" command? Can that 2nd function tell if it is being run in a trigger?
No. Doesn't really matter whether you use PERFORM or not.
regards, tom lane