Re: another idea for changing global configuration settings from SQL

On 11/15/12 12:53 PM, Peter Eisentraut wrote:
> We already have the ability to store in pg_db_role_setting configuration
> settings for
>
> specific user, specific database
> specific user, any database
> any user, specific database
>
> The existing infrastructure would also support
>
> any user, any database (= all the time)
>
> All you'd need is to add
>
> ApplySetting(InvalidOid, InvalidOid, relsetting, PGC_S_$SOMETHING);
>
> in postinit.c, and have some SQL command to modify this setting.

Here is a patch for that.

The internals are straightforward. Actually, we might want to refactor
this a bit later, unifying the AlterRoleSet and AlterDatabaseSet parse
nodes and the functions that do the work, because it's really all the same.

The SQL level interface is a bit odd. The existing facilities are

ALTER ROLE / SET
ALTER DATABASE / SET
ALTER ROLE / IN DATABASE / SET

Since the original design somehow considered roles to be superior to
databases in this regard, I added the global setting as ALTER ROLE ALL
SET ..., but that's obviously arbitrary. Most other variants would
probably be much more invasive, though.