On Mon, Nov 10, 2014 at 6:55 AM, Amit Kapila <amit.kapil...@gmail.com> wrote: > I thought that in general if user has the API to register the custom path > methods, it should have some way to unregister them and also user might > need to register some different custom path methods after unregistering > the previous one's. I think we should see what Robert or others have to > say about this point before trying to provide such an API.
I wouldn't bother. As KaiGai says, if you want to shut the functionality off, the provider itself can provide a GUC. Also, we really have made no effort to ensure that loadable modules can be safely unloaded, or hooked functions safely-unhooked. ExecutorRun_hook is a good example. Typical of hook installation is this: prev_ExecutorRun = ExecutorRun_hook; ExecutorRun_hook = pgss_ExecutorRun; Well, if multiple extensions use this hook, then there's no hope of unloading them exception in reverse order of installation. We essentially end up creating a singly-linked list of hook users, but with the next-pointers stored in arbitrarily-named, likely-static variables owned by the individual extensions, so that nobody can actually traverse it. This might be worth fixing as part of a concerted campaign to make UNLOAD work, but unless somebody's really going to do that I see little reason to hold this to a higher standard than we apply elsewhere. The ability to remove extensions from this hook won't be valuable by itself. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers