Slony-I 2.2.11 Documentation
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# 8.127. subscribeset(p_omit_copy integer, p_sub_forward integer, p_sub_receiver integer, p_sub_provider boolean, p_sub_set boolean)

Function Properties

Language: PLPGSQL

Return Type: bigint

subscribeSet (sub_set, sub_provider, sub_receiver, sub_forward, omit_copy) Makes sure that the receiver is not the provider, then stores the subscription, and publishes the SUBSCRIBE_SET event to other nodes. If omit_copy is true, then no data copy will be done.

    declare
    	v_set_origin		int4;
    	v_ev_seqno			int8;
    	v_ev_seqno2			int8;
    	v_rec			record;
    begin
    	-- ----
    	-- Grab the central configuration lock
    	-- ----
    	lock table sl_config_lock;

    	--
    	-- Check that the receiver exists
    	--
    	if not exists (select no_id from sl_node where no_id=
    	       	      p_sub_receiver) then
    		      raise exception 'Slony-I: subscribeSet() receiver % does not exist' , p_sub_receiver;
    	end if;

    	--
    	-- Check that the provider exists
    	--
    	if not exists (select no_id from sl_node where no_id=
    	       	      p_sub_provider) then
    		      raise exception 'Slony-I: subscribeSet() provider % does not exist' , p_sub_provider;
    	end if;

    	-- ----
    	-- Check that the origin and provider of the set are remote
    	-- ----
    	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(): set % not found', p_sub_set;
    	end if;
    	if v_set_origin = p_sub_receiver then
    		raise exception
    				'Slony-I: subscribeSet(): set origin and receiver cannot be identical';
    	end if;
    	if p_sub_receiver = p_sub_provider then
    		raise exception
    				'Slony-I: subscribeSet(): set provider and receiver cannot be identical';
    	end if;
    	-- ----
    	-- Check that this is called on the origin node
    	-- ----
    	if v_set_origin != getLocalNodeId('_schemadoc') then
    		raise exception 'Slony-I: subscribeSet() must be called on origin';
    	end if;

    	-- ---
    	-- Verify that the provider is either the origin or an active subscriber
    	-- Bug report #1362
    	-- ---
    	if v_set_origin <> p_sub_provider then
    		if not exists (select 1 from sl_subscribe
    			where sub_set = p_sub_set and
                                  sub_receiver = p_sub_provider and
    			      sub_forward and sub_active) then
    			raise exception 'Slony-I: subscribeSet(): provider % is not an active forwarding node for replication set %', p_sub_provider, p_sub_set;
    		end if;
    	end if;

    	-- ---
    	-- Enforce that all sets from one origin are subscribed
    	-- using the same data provider per receiver.
    	-- ----
    	if not exists (select 1 from sl_subscribe
    			where sub_set = p_sub_set and sub_receiver = p_sub_receiver) then
    		--
    		-- New subscription - error out if we have any other subscription
    		-- from that origin with a different data provider.
    		--
    		for v_rec in select sub_provider from sl_subscribe
    				join sl_set on set_id = sub_set
    				where set_origin = v_set_origin and sub_receiver = p_sub_receiver
    		loop
    			if v_rec.sub_provider <> p_sub_provider then
    				raise exception 'Slony-I: subscribeSet(): wrong provider % - existing subscription from origin % users provider %',
    					p_sub_provider, v_set_origin, v_rec.sub_provider;
    			end if;
    		end loop;
    	else
    		--
    		-- Existing subscription - in case the data provider changes and
    		-- there are other subscriptions, warn here. subscribeSet_int()
    		-- will currently change the data provider for those sets as well.
    		--
    		for v_rec in select set_id, sub_provider from sl_subscribe
    				join sl_set on set_id = sub_set
    				where set_origin = v_set_origin and sub_receiver = p_sub_receiver
    				and set_id <> p_sub_set
    		loop
    			if v_rec.sub_provider <> p_sub_provider then
    				raise exception 'Slony-I: subscribeSet(): also data provider for set % use resubscribe instead',
    					v_rec.set_id;
    			end if;
    		end loop;
    	end if;

    	-- ----
    	-- Create the SUBSCRIBE_SET event
    	-- ----
    	v_ev_seqno :=  createEvent('_schemadoc', 'SUBSCRIBE_SET',
    			p_sub_set::text, p_sub_provider::text, p_sub_receiver::text,
    			case p_sub_forward when true then 't' else 'f' end,
    			case p_omit_copy when true then 't' else 'f' end
                            );

    	-- ----
    	-- Call the internal procedure to store the subscription
    	-- ----
    	v_ev_seqno2:=subscribeSet_int(p_sub_set, p_sub_provider,
    			p_sub_receiver, p_sub_forward, p_omit_copy);

    	if v_ev_seqno2 is not null then
    	   v_ev_seqno:=v_ev_seqno2;
    	 end if;

    	return v_ev_seqno;
    end;

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