On 2014-06-20 17:29:33 -0400, Tom Lane wrote:
> Andres Freund <andres@2ndquadrant.com> writes:
> > On 2014-06-20 16:50:15 -0400, Alvaro Herrera wrote:
> >> Non-unique indexes in indexing.h
> >> already bear a standard comment that they are not used for syscache.
> >> The only exception was added recently in f01d1ae3a104019:
> >> DECLARE_INDEX(pg_class_tblspc_relfilenode_index, 3455, on pg_class using btree(reltablespace oid_ops, relfilenode
oid_ops));
>
> > There's no NULLs in here. It can have duplicates, but in that it's far
> > from alone.
>
> I think Alvaro was complaining that it's alone in lacking this comment:
> /* This following index is not used for a cache and is not unique */
>
> But TBH, I don't think those comments are worth much. I'd rather get
> rid of them all and instead add an Assert to the cache code enforcing
> that any index underlying a catcache is unique. It looks like the
> easiest place to do that is InitCatCachePhase2 --- that's the only place
> in catcache.c that actually opens the underlying index directly.
>
> I'd like to also have an Assert in there that the index columns are
> marked NOT NULL, but not sure if they actually all are marked that
> way today.
Sounds sensible. If they aren't marking them as such hopefully isn't
problematic...
Greetings,
Andres Freund
-- Andres Freund http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
Services
