1.73. logswitch_finish( )

    DECLARE
    	v_current_status	int4;
    	v_dummy				record;
    BEGIN
    	-- ----
    	-- Grab the central configuration lock to prevent race conditions
    	-- while changing the sl_log_status sequence value.
    	-- ----
    	lock table sl_config_lock;
    
    	-- ----
    	-- Get the current log status.
    	-- ----
    	select last_value into v_current_status from sl_log_status;
    
    	-- ----
    	-- status value 0 or 1 means that there is no log switch in progress
    	-- ----
    	if v_current_status = 0 or v_current_status = 1 then
    		return 0;
    	end if;
    
    	-- ----
    	-- status = 2: sl_log_1 active, cleanup sl_log_2
    	-- ----
    	if v_current_status = 2 then
    		-- ----
    		-- The cleanup thread calls us after it did the delete and
    		-- vacuum of both log tables. If sl_log_2 is empty now, we
    		-- can truncate it and the log switch is done.
    		-- ----
    		for v_dummy in select 1 from sl_log_2 loop
    			-- ----
    			-- Found a row ... log switch is still in progress.
    			-- ----
    			raise notice 'Slony-I: log switch to sl_log_1 still in progress - sl_log_2 not truncated';
    			return -1;
    		end loop;
    
    		raise notice 'Slony-I: log switch to sl_log_1 complete - truncate sl_log_2';
    		truncate sl_log_2;
    		perform "pg_catalog".setval('sl_log_status', 0);
    		-- Run addPartialLogIndices() to try to add indices to unused sl_log_? table
    		perform addPartialLogIndices();
    
    		return 1;
    	end if;
    
    	-- ----
    	-- status = 3: sl_log_2 active, cleanup sl_log_1
    	-- ----
    	if v_current_status = 3 then
    		-- ----
    		-- The cleanup thread calls us after it did the delete and
    		-- vacuum of both log tables. If sl_log_2 is empty now, we
    		-- can truncate it and the log switch is done.
    		-- ----
    		for v_dummy in select 1 from sl_log_1 loop
    			-- ----
    			-- Found a row ... log switch is still in progress.
    			-- ----
    			raise notice 'Slony-I: log switch to sl_log_2 still in progress - sl_log_1 not truncated';
    			return -1;
    		end loop;
    
    		raise notice 'Slony-I: log switch to sl_log_2 complete - truncate sl_log_1';
    		truncate sl_log_1;
    		perform "pg_catalog".setval('sl_log_status', 1);
    		-- Run addPartialLogIndices() to try to add indices to unused sl_log_? table
    		perform addPartialLogIndices();
    		return 2;
    	end if;
    END;