Slony-I 2.2.10 Documentation
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# 8.66. failoverset_int(p_last_seqno integer, p_backup_node integer, p_failed_node bigint)

Function Properties

Language: PLPGSQL

Return Type: integer

FUNCTION failoverSet_int (failed_node, backup_node, set_id, wait_seqno) Finish failover for one set.

    declare
    	v_row				record;
    	v_last_sync			int8;
    	v_set				int4;
    begin
    	-- ----
    	-- Grab the central configuration lock
    	-- ----
    	lock table sl_config_lock;

    	SELECT max(ev_seqno) into v_last_sync FROM sl_event where
    		   ev_origin=p_failed_node;
    	if v_last_sync > p_last_seqno then
    	   -- this node is ahead of the last sequence number from the
    	   -- failed node that the backup node has.
    	   -- this node must unsubscribe from all sets from the origin.
    	   for v_set in select set_id from sl_set where
    		set_origin=p_failed_node
    		loop
    			raise warning 'Slony is dropping the subscription of set % found sync %s bigger than %s '
    			, v_set, v_last_sync::text, p_last_seqno::text;
    			perform unsubscribeSet(v_set,
    				   getLocalNodeId('_schemadoc'),
    				   true);
    		end loop;
    		delete from sl_event where ev_origin=p_failed_node
    			   and ev_seqno > p_last_seqno;
    	end if;
    	-- ----
    	-- Change the origin of the set now to the backup node.
    	-- On the backup node this includes changing all the
    	-- trigger and protection stuff
    	for v_set in select set_id from sl_set where
    		set_origin=p_failed_node
    	loop
    	-- ----
    	   if p_backup_node = getLocalNodeId('_schemadoc') then
    	   	  	delete from sl_setsync
    				where ssy_setid = v_set;
    			delete from sl_subscribe
    				where sub_set = v_set
    					and sub_receiver = p_backup_node;
    			update sl_set
    				set set_origin = p_backup_node
    				where set_id = v_set;
    			 update sl_subscribe
    						set sub_provider=p_backup_node
    					  	FROM sl_node receive_node
    					   where sub_set = v_set
    					   and sub_provider=p_failed_node
    					   and sub_receiver=receive_node.no_id
    					   and receive_node.no_failed=false;

    			for v_row in select * from sl_table
    				where tab_set = v_set
    				order by tab_id
    			loop
    				perform alterTableConfigureTriggers(v_row.tab_id);
    			end loop;
    	else
    		raise notice 'deleting from sl_subscribe all rows with receiver %',
    		p_backup_node;

    			delete from sl_subscribe
    					  where sub_set = v_set
    					  and sub_receiver = p_backup_node;

    			update sl_subscribe
    				 		set sub_provider=p_backup_node
    						FROM sl_node receive_node
    					   where sub_set = v_set
    					    and sub_provider=p_failed_node
    						 and sub_provider=p_failed_node
    					   and sub_receiver=receive_node.no_id
    					   and receive_node.no_failed=false;
    			update sl_set
    					   set set_origin = p_backup_node
    				where set_id = v_set;
    			-- ----
    			-- If we are a subscriber of the set ourself, change our
    			-- setsync status to reflect the new set origin.
    			-- ----
    			if exists (select true from sl_subscribe
    			   where sub_set = v_set
    			   	and sub_receiver = getLocalNodeId(
    						'_schemadoc'))
    			then
    				delete from sl_setsync
    					   where ssy_setid = v_set;

    				select coalesce(max(ev_seqno), 0) into v_last_sync
    					   from sl_event
    					   where ev_origin = p_backup_node
    					   and ev_type = 'SYNC';
    				if v_last_sync > 0 then
    				   insert into sl_setsync
    					(ssy_setid, ssy_origin, ssy_seqno,
    					ssy_snapshot, ssy_action_list)
    					select v_set, p_backup_node, v_last_sync,
    					ev_snapshot, NULL
    					from sl_event
    					where ev_origin = p_backup_node
    						and ev_seqno = v_last_sync;
    				else
    					insert into sl_setsync
    					(ssy_setid, ssy_origin, ssy_seqno,
    					ssy_snapshot, ssy_action_list)
    					values (v_set, p_backup_node, '0',
    					'1:1:', NULL);
    				end if;
    			end if;
    		end if;
    	end loop;

    	--If there are any subscriptions with
    	--the failed_node being the provider then
    	--we want to redirect those subscriptions
    	--to come from the backup node.
    	--
    	-- The backup node should be a valid
    	-- provider for all subscriptions served
    	-- by the failed node. (otherwise it
    	-- wouldn't be a allowable backup node).
    --	delete from sl_subscribe
    --		   where sub_receiver=p_backup_node;

    	update sl_subscribe
    	       set sub_provider=p_backup_node
    	       from sl_node
    	       where sub_provider=p_failed_node
    	       and sl_node.no_id=sub_receiver
    	       and sl_node.no_failed=false
    		   and sub_receiver<>p_backup_node;

    	update sl_subscribe
    	       set sub_provider=(select set_origin from
    		   	   sl_set where set_id=
    			   sub_set)
    			where sub_provider=p_failed_node
    			and sub_receiver=p_backup_node;

    	update sl_node
    		   set no_active=false WHERE
    		   no_id=p_failed_node;

    	-- Rewrite sl_listen table
    	perform RebuildListenEntries();

    	return p_failed_node;
    end;

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