Re: [PATCH] Add session_preload_libraries configuration parameter

Peter Eisentraut <peter_e@gmx.net> writes:
> local_preload_libraries allows unprivileged users to preload whitelisted
> libraries.  session_preload_libraries allows superusers to preload any
> library.  It's hard to see how to consolidate those, at least without
> adding another setting that whitelists the libraries somehow, at which
> point you haven't really gained anything in terms of complexity.

Good point.

> I don't know of any actual legitimate uses of local_preload_libraries.
> I recall that the plpgsql debugger was meant to use it, but doesn't
> anymore.  So it's hard to judge what to do about this, without any
> actual use cases.

Well there's my preprepare thing at 
 https://github.com/dimitri/preprepare

I don't think that the whitelisting is actually used in a way to allow
for non superusers to load modules in the field, because the only way to
do that with local_preload_libraries that I know of is to edit the
postgresql.conf file and reload.
 alter role dim set local_preload_libraries = 'auto_explain'; ERROR:  55P02: parameter "local_preload_libraries" cannot
beset after connection start
 

That said, I think we could go with your current patch and revise the
local_preload_libraries down the road in the 9.4 development cycle.
Having both for a while is a good way to better understand if they are
useful to have together.

Going to mark your patch ready for commiter, thanks!

Regards,
-- 
Dimitri Fontaine
http://2ndQuadrant.fr     PostgreSQL : Expertise, Formation et Support