Actions internes pour abonner le récepteur sub_receiver à l'ensemble sub_set.

declare
        p_sub_set                       alias for $1;
        p_sub_provider          alias for $2;
        p_sub_receiver          alias for $3;
        p_sub_forward           alias for $4;
        v_set_origin            int4;
        v_sub_row                       record;
begin
        -- ----
        -- Grab the central configuration lock
        -- ----
        lock table sl_config_lock;

        -- ----
        -- Provider change is only allowed for active sets
        -- ----
        if p_sub_receiver = getLocalNodeId('_schemadoc') then
                select sub_active into v_sub_row from sl_subscribe
                                where sub_set = p_sub_set
                                and sub_receiver = p_sub_receiver;
                if found then
                        if not v_sub_row.sub_active then
                                raise exception 'Slony-I: subscribeSet_int(): set % is not active, cannot change provider',
                                                p_sub_set;
                        end if;
                end if;
        end if;

        -- ----
        -- Try to change provider and/or forward for an existing subscription
        -- ----
        update sl_subscribe
                        set sub_provider = p_sub_provider,
                                sub_forward = p_sub_forward
                        where sub_set = p_sub_set
                        and sub_receiver = p_sub_receiver;
        if found then
                -- ----
                -- Rewrite sl_listen table
                -- ----
                perform RebuildListenEntries();

                return p_sub_set;
        end if;

        -- ----
        -- Not found, insert a new one
        -- ----
        if not exists (select true from sl_path
                        where pa_server = p_sub_provider
                        and pa_client = p_sub_receiver)
        then
                insert into sl_path
                                (pa_server, pa_client, pa_conninfo, pa_connretry)
                                values 
                                (p_sub_provider, p_sub_receiver, 
                                '<event pending>', 10);
        end if;
        insert into sl_subscribe
                        (sub_set, sub_provider, sub_receiver, sub_forward, sub_active)
                        values (p_sub_set, p_sub_provider, p_sub_receiver,
                                p_sub_forward, false);

        -- ----
        -- If the set origin is here, then enable the subscription
        -- ----
        select set_origin into v_set_origin
                        from sl_set
                        where set_id = p_sub_set;
        if not found then
                raise exception 'Slony-I: subscribeSet_int(): set % not found', p_sub_set;
        end if;

        if v_set_origin = getLocalNodeId('_schemadoc') then
                perform createEvent('_schemadoc', 'ENABLE_SUBSCRIPTION', 
                                p_sub_set, p_sub_provider, p_sub_receiver, 
                                case p_sub_forward when true then 't' else 'f' end);
                perform enableSubscription(p_sub_set, 
                                p_sub_provider, p_sub_receiver);
        end if;

        -- ----
        -- Rewrite sl_listen table
        -- ----
        perform RebuildListenEntries();

        return p_sub_set;
end;