Andres Freund <andres@2ndquadrant.com> writes:
> 3b) Add catcache 'filter' that ensures the cache stays unique and use
> that for the mapping
> I slightly prefer 3b) because it's smaller, what's your opinions?
This is just another variation on the theme of kluging the catcache to
do something it shouldn't. You're still building a catcache on a
non-unique index, and that is going to lead to trouble.
(I'm a bit surprised that there is no Assert in catcache.c checking
that the index nominated to support a catcache is unique ...)
regards, tom lane