Simon Riggs <simon@2ndQuadrant.com> writes:
> Avoiding a scan before running pg_upgrade is just a performance
> optimisation. I don't think we should be optimising an upgrade in this
> way, especially since sane people do database backups before upgrade
> anyway. The optimisation is misplaced. The fact that we are actively
> planning to have code in the server that only gets executed if
> pg_upgrade screws up scares the hell out of me. If someone else
> suggested it you'd give them both barrels.
If we were putting in new, never tested, code of that description I'd be
scared of it too. Code that's been there since the previous century,
however, is not even remotely the same type of case. Arguably, there is
bigger risk in removing it from tqual.c than not doing so --- it is not
impossible to screw up the removal ...
regards, tom lane