Gavin Sherry <swm@linuxworld.com.au> writes:
> There have been a few discussions about triggers on system tables in
> the past and the problems with such triggers seem to be:
I think the killer problem is that we couldn't allow triggers on system
tables to do very much. By definition, the database is in an inconsistent
state if we are in the middle of updating system tables. We can't allow
arbitrary bits of SQL to run then.
It might be feasible to allow AFTER triggers on system tables, since
those don't actually fire until end of statement, at which point things
are hopefully consistent again. I don't even want to think about
allowing BEFORE triggers.
regards, tom lane