pgsql-bugs(at)postgresql(dot)org writes:
> Following is the example of sql script that crashes server if you
> remove marked comments (this is not real code, just test one).
> May be i am doing something wrong???
Changing the trigger set on a relation from within a trigger on that
same relation is not a good plan. When you return from the trigger,
the trigger-calling code is now holding a dangling pointer to
no-longer-valid trigger data. Instant core dump.
I'm not clear on why you feel you need to do that, but I'd suggest
finding another way. Perhaps a rule instead of a trigger? Or redesign
your table structure to make the problem go away in the first place?
regards, tom lane