Re: CREATE FUNCTION ... SEARCH { DEFAULT | SYSTEM | SESSION }

On Sat, 2023-08-12 at 09:15 -0400, Joe Conway wrote:
> It isn't clear to me what is the precise difference between  DEFAULT
> and 
> SESSION

The the current patch, SESSION always gets the search path from the
session, while DEFAULT is controlled by the GUC
safe_function_search_path. If the GUC is false (the default) then
DEFAULT and SESSION are the same. If the GUC is true, then DEFAULT and
SYSTEM are the same.

There are alternatives to using a GUC to differentiate them. The main
point of this patch is to capture what the user intends in a convenient
and forward-compatible way. If the user specifies nothing at all, they
get DEFAULT, and we could treat that specially in various ways to move
toward safety while minimizing breakage.

> 
> Personally I think having pg_temp in the SYSTEM search path makes
> sense 
> for temp tables

The patch doesn't change this behavior -- SYSTEM (without any other
SET) gives you "pg_catalog, pg_temp" and there's no way to exclude
pg_temp entirely.

My point was that by capturing the user's intent with SEARCH SYSTEM, it
gives us a bit more freedom to have these kinds of discussions later.
And it's certainly easier for the user to specify SEARCH SYSTEM than
"SET search_path = pg_catalog, pg_temp".

Regards,
	Jeff Davis