Tom Lane wrote:
So I coded up a patch for this, based on the idea of creating a
quasi-subtransaction that affects only GUC while entering/exiting a
function that has GUC settings attached.  The specified settings are
applied as if by SET LOCAL before starting function execution, and then
they drop out during "subtransaction" exit.  (I'll post the code to
pgsql-patches in a moment.)

But on reflection I realize that there are some interesting properties
to this approach:

* if you do "SET LOCAL foo" when you are in a function that has a
  "SET foo" property, the setting disappears at function exit.  But if
  you do "SET foo" it persists.  This might be OK, but it seems a bit odd.
That seems OK - the same happens inside a BEGIN/EXCEPTION/END block, no?

* in fact, if you do "SET LOCAL foo" when you are in a function that has
  any "SET" property at all, the setting disappears at function exit,
  whether foo was one of the variables SET by the function definition or
  not.
Hm... That is a bit surprising... Maybe all functions should create a
such GUC-only substransaction-like thing. That might create problems
for inlining - but only if you can actually change GUCs from plsql
function, which maybe you cant...

We could perhaps get away with defining that as being the behavior,
but it doubtless will surprise someone sometime.  What *should* these
interactions be like, and has anyone got an idea how to implement their
suggestion?
What will happen if you have two functions, foo and bar, were the search-path
is overridden for foo, and foo calls bar. I guess bar would be executed with
foo's overridden searchpath. Thats seems a bit surprising - I'd make more
sense to me if bar would use the session's search-path, but that seems hard
to do... Especially because bar *should* use foo's searchpath if foo contained
an explicit "SET LOCAL search_path"

Or maybe I'm just crazy, and the current behavior is fine....

greetings, Florian Pflug


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