I wrote:
> But even if we can't make that work, it's not grounds for reserving
> PERSISTENT. Instead I'd be inclined to forget about "RESET PERSISTENT"
> syntax and use, say, SET PERSISTENT var_name TO DEFAULT to mean that.
> (BTW, I wonder what behavior that syntax has now in your patch.)
In fact, rereading this, I wonder why you think "RESET PERSISTENT"
is a good idea even if there were no bison issues with it. We don't
write RESET LOCAL or RESET SESSION, so it seems asymmetric to have
RESET PERSISTENT.
regards, tom lane