Prépare l'exécution du script DDL sur l'origine.

declare
        p_set_id                        alias for $1;
        p_only_on_node          alias for $2;
        v_set_origin            int4;
begin
        -- ----
        -- Grab the central configuration lock
        -- ----
        lock table sl_config_lock;

        
        -- ----
        -- Check that the set exists and originates here
        -- unless only_on_node was specified (then it can be applied to
        -- that node because that is what the user wanted)
        -- ----
        select set_origin into v_set_origin
                        from sl_set
                        where set_id = p_set_id
                        for update;
        if not found then
                raise exception 'Slony-I: set % not found', p_set_id;
        end if;

        if p_only_on_node = -1 then
                if v_set_origin <> getLocalNodeId('_schemadoc') then
                        raise exception 'Slony-I: set % does not originate on local node',
                                p_set_id;
                end if;
                -- ----
                -- Create a SYNC event, run the script and generate the DDL_SCRIPT event
                -- ----
                perform createEvent('_schemadoc', 'SYNC', NULL);
                perform alterTableRestore(tab_id) from sl_table where tab_set in (select set_id from sl_set where set_origin = getLocalNodeId('_schemadoc'));
        else
                -- ----
                -- If doing "only on one node" - restore ALL tables irrespective of set
                -- ----
                perform alterTableRestore(tab_id) from sl_table;
        end if;
        return 1;
end;