1.79. mergeset( integer, integer )

Function Properties

Language: PLPGSQL

Return Type: bigint

Generate MERGE_SET event to request that sets be merged together. Both sets must exist, and originate on the same node. They must be subscribed by the same set of nodes.

declare
	p_set_id			alias for $1;
	p_add_id			alias for $2;
	v_origin			int4;
begin
	-- ----
	-- Grab the central configuration lock
	-- ----
	lock table sl_config_lock;
	
	-- ----
	-- Check that both sets exist and originate here
	-- ----
	if p_set_id = p_add_id then
		raise exception 'Slony-I: merged set ids cannot be identical';
	end if;
	select set_origin into v_origin from sl_set
			where set_id = p_set_id;
	if not found then
		raise exception 'Slony-I: set % not found', p_set_id;
	end if;
	if v_origin != getLocalNodeId('_schemadoc') then
		raise exception 'Slony-I: set % does not originate on local node',
				p_set_id;
	end if;

	select set_origin into v_origin from sl_set
			where set_id = p_add_id;
	if not found then
		raise exception 'Slony-I: set % not found', p_add_id;
	end if;
	if v_origin != getLocalNodeId('_schemadoc') then
		raise exception 'Slony-I: set % does not originate on local node',
				p_add_id;
	end if;

	-- ----
	-- Check that both sets are subscribed by the same set of nodes
	-- ----
	if exists (select true from sl_subscribe SUB1
				where SUB1.sub_set = p_set_id
				and SUB1.sub_receiver not in (select SUB2.sub_receiver
						from sl_subscribe SUB2
						where SUB2.sub_set = p_add_id))
	then
		raise exception 'Slony-I: subscriber lists of set % and % are different',
				p_set_id, p_add_id;
	end if;

	if exists (select true from sl_subscribe SUB1
				where SUB1.sub_set = p_add_id
				and SUB1.sub_receiver not in (select SUB2.sub_receiver
						from sl_subscribe SUB2
						where SUB2.sub_set = p_set_id))
	then
		raise exception 'Slony-I: subscriber lists of set % and % are different',
				p_add_id, p_set_id;
	end if;

	-- ----
	-- Check that all ENABLE_SUBSCRIPTION events for the set are confirmed
	-- ----
	if exists (select true from sl_event
			where ev_type = 'ENABLE_SUBSCRIPTION'
			and ev_data1 = p_add_id::text
			and ev_seqno > (select max(con_seqno) from sl_confirm
					where con_origin = ev_origin
					and con_received::text = ev_data3))
	then
		raise exception 'Slony-I: set % has subscriptions in progress - cannot merge',
				p_add_id;
	end if;
			  

	-- ----
	-- Create a SYNC event, merge the sets, create a MERGE_SET event
	-- ----
	perform createEvent('_schemadoc', 'SYNC', NULL);
	perform mergeSet_int(p_set_id, p_add_id);
	return  createEvent('_schemadoc', 'MERGE_SET', 
			p_set_id::text, p_add_id::text);
end;