Ticket #3461. The column cache and result set alias cache mechanisms are
prone to this kind of error and need to be refactored. This check-in should
be considered a temporary fix in advance of a more general redesign of the
whole mechanism. (CVS 5841)
FossilOrigin-Name: 1fa3bbd8220ce073e91935ea362b6f5d5d6d2859
