On 2013-07-22 17:04:06 -0400, Alvaro Herrera wrote: > Pavan Deolasee escribió: > > Hello, > > > > While doing some tests, I observed that expression indexes can malfunction > > if the underlying expression changes. > > [...] > > > Perhaps this is a known behaviour/limitation, but I could not find that in > > the documentation. But I wonder if it makes sense to check for dependencies > > during function alteration and complain. Or there are other reasons why we > > can't do that and its a much larger problem than what I'm imagining ? > > This is a tough problem. The dependency mechanism has no way to keep > track of this kind of dependency; all it does is prevent the function > from being dropped altogether, but preventing it from acquiring a > conflicting definition is outside its charter. > > One way to attack this would be registering dependencies of a new kind > on functions used by index expressions. Then CREATE OR REPLACE function > could reject alteration for such functions. I don't know if we care > enough about this case.
I think changing the results of a immutable function violates the contract enough to make this the user's fault. Also the other solutions seem hard to achieve ;) Greetings, Andres Freund -- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
