Re: Configurable location for extension .control files

Oliver Charles <ollie@ocharles.org.uk> writes:
> I am working with the NixOS Linux Distribution [nixos], which has a 
> fairly radical approach to package management. If you aren't familiar 
> with it, essentially all packages are installed in isolation - such that 
> packages cannot interfere with each other.

Maybe you need to rethink that concept.  Surely there are many other
cases where package A extends package B and needs to be installed
somewhere where B is expecting to look for extensions.

> This is causing a bit of a problem with PostgreSQL extensions that are 
> usually installed via CREATE EXTENSION. For extensions to be used, a 
> .control file must be placed in SHAREDIR/extension, but this is not 
> possible under NixOS as once PostgreSQL is installed that directory is 
> essentially immutable.

> What wolud work best for us is to allow this path to be configurable, 
> ideally through either an environment variable, command line switch, or 
> (and this is the least desirable) a postgresql.conf option.

Basically, none of those are likely to get accepted because of security
concerns.  We *don't* want this path to be run-time adjustable.
        regards, tom lane