Update of /home/cvsd/slony1/slony1-engine/src/backend
In directory main.slony.info:/tmp/cvs-serv20468

Modified Files:
      Tag: REL_1_2_STABLE
	slony1_funcs.sql 
Log Message:
Backport automatic listen path generator from CVS HEAD...

Tests done thus far:
- I added a "testlistenpath" test to the set of tests, which is working
  fine

- JP Fletcher did some testing of cases where he saw things break, and
  this change addressed those cases


Index: slony1_funcs.sql
===================================================================
RCS file: /home/cvsd/slony1/slony1-engine/src/backend/slony1_funcs.sql,v
retrieving revision 1.98.2.23
retrieving revision 1.98.2.24
diff -C2 -d -r1.98.2.23 -r1.98.2.24
*** slony1_funcs.sql	13 Sep 2007 14:20:29 -0000	1.98.2.23
--- slony1_funcs.sql	25 Sep 2007 18:33:38 -0000	1.98.2.24
***************
*** 5138,5173 ****
  as '
  declare
! 	v_receiver record ;
! 	v_provider record ;
! 	v_origin record ;
! 	v_reachable int4[] ;
  begin
  	-- First remove the entire configuration
  	delete from @NAMESPACE at .sl_listen;
  
! 	-- Loop over every possible pair of receiver and provider
! 	for v_receiver in select no_id from @NAMESPACE at .sl_node loop
! 		for v_provider in select pa_server as no_id from @NAMESPACE at .sl_path where pa_client = v_receiver.no_id loop
  
! 			-- Find all nodes that v_provider.no_id can receiver events from without using v_receiver.no_id			
! 			for v_origin in select * from @NAMESPACE at .ReachableFromNode(v_provider.no_id, array[v_receiver.no_id]) as r(no_id) loop
  
! 				-- If v_receiver.no_id subscribes a set from v_provider.no_id, events have to travel the same
! 				-- path as the data. Ignore possible sl_listen that would break that rule.
! 				perform 1 from @NAMESPACE at .sl_subscribe
! 					join @NAMESPACE at .sl_set on sl_set.set_id = sl_subscribe.sub_set
! 		 			where
! 						sub_receiver = v_receiver.no_id and
! 						sub_provider != v_provider.no_id and
! 						set_origin = v_origin.no_id ;
! 				if not found then
! 					insert into @NAMESPACE at .sl_listen (li_receiver, li_provider, li_origin)
! 						values (v_receiver.no_id, v_provider.no_id, v_origin.no_id) ;
! 				end if ;
  
  
! 			end loop ;
  
- 		end loop ;
  	end loop ;
  
--- 5138,5219 ----
  as '
  declare
! 	v_row	record;
  begin
  	-- First remove the entire configuration
  	delete from @NAMESPACE at .sl_listen;
  
! 	-- Second populate the sl_listen configuration with a full
! 	-- network of all possible paths.
! 	insert into @NAMESPACE at .sl_listen
! 				(li_origin, li_provider, li_receiver)
! 			select pa_server, pa_server, pa_client from @NAMESPACE at .sl_path;
! 	while true loop
! 		insert into @NAMESPACE at .sl_listen
! 					(li_origin, li_provider, li_receiver)
! 			select distinct li_origin, pa_server, pa_client
! 				from @NAMESPACE at .sl_listen, @NAMESPACE at .sl_path
! 				where li_receiver = pa_server
! 				  and li_origin <> pa_client
! 			except
! 			select li_origin, li_provider, li_receiver
! 				from @NAMESPACE at .sl_listen;
  
! 		if not found then
! 			exit;
! 		end if;
! 	end loop;
  
! 	-- We now replace specific event-origin,receiver combinations
! 	-- with a configuration that tries to avoid events arriving at
! 	-- a node before the data provider actually has the data ready.
  
+ 	-- Loop over every possible pair of receiver and event origin
+ 	for v_row in select N1.no_id as receiver, N2.no_id as origin
+ 			from @NAMESPACE at .sl_node as N1, @NAMESPACE at .sl_node as N2
+ 			where N1.no_id <> N2.no_id
+ 	loop
+ 		-- 1st choice:
+ 		-- If we use the event origin as a data provider for any
+ 		-- set that originates on that very node, we are a direct
+ 		-- subscriber to that origin and listen there only.
+ 		if exists (select true from @NAMESPACE at .sl_set, @NAMESPACE at .sl_subscribe
+ 				where set_origin = v_row.origin
+ 				  and sub_set = set_id
+ 				  and sub_provider = v_row.origin
+ 				  and sub_receiver = v_row.receiver
+ 				  and sub_active)
+ 		then
+ 			delete from @NAMESPACE at .sl_listen
+ 				where li_origin = v_row.origin
+ 				  and li_receiver = v_row.receiver;
+ 			insert into @NAMESPACE at .sl_listen (li_origin, li_provider, li_receiver)
+ 				values (v_row.origin, v_row.origin, v_row.receiver);
+ 			continue;
+ 		end if;
  
! 		-- 2nd choice:
! 		-- If we are subscribed to any set originating on this
! 		-- event origin, we want to listen on all data providers
! 		-- we use for this origin. We are a cascaded subscriber
! 		-- for sets from this node.
! 		if exists (select true from @NAMESPACE at .sl_set, @NAMESPACE at .sl_subscribe
! 						where set_origin = v_row.origin
! 						  and sub_set = set_id
! 						  and sub_receiver = v_row.receiver
! 						  and sub_active)
! 		then
! 			delete from @NAMESPACE at .sl_listen
! 					where li_origin = v_row.origin
! 					  and li_receiver = v_row.receiver;
! 			insert into @NAMESPACE at .sl_listen (li_origin, li_provider, li_receiver)
! 					select distinct set_origin, sub_provider, v_row.receiver
! 						from @NAMESPACE at .sl_set, @NAMESPACE at .sl_subscribe
! 						where set_origin = v_row.origin
! 						  and sub_set = set_id
! 						  and sub_receiver = v_row.receiver
! 						  and sub_active;
! 			continue;
! 		end if;
  
  	end loop ;