DECLARE 	   
  timer_id TIMER;  
  do_log BOOLEAN;  
  n_date date;
  NOT_CONN EXCEPTION;
  PRAGMA EXCEPTION_INIT(NOT_CONN,-1089); 
  NOT_CONN1 EXCEPTION;
  PRAGMA EXCEPTION_INIT(NOT_CONN1,-3113);   
BEGIN
    UN := SUBSTR(Get_Application_Property(USERNAME),1,32); 
    PW := SUBSTR(Get_Application_Property(PASSWORD),1,32);
    PW1 := SUBSTR(Get_Application_Property(PASSWORD),1,32);
    CS := ltrim(rtrim(SUBSTR(Get_Application_Property(CONNECT_STRING),1,30)));
    IF cs IS NOT NULL THEN
      PW := PW||'@'||CS;
    END IF;  	
.....
      timer_id := FIND_TIMER ('LOAD_TIMER');
      IF Id_Null(Timer_id) THEN
         Timer_id := Create_timer('LOAD_TIMER', 6000, NO_REPEAT);
      ELSE
        SET_TIMER(timer_id, 6000, NO_REPEAT);
      END IF;    	
 execute_query;
EXCEPTION WHEN 	NOT_CONN or NOT_CONN1  
	THEN
	 do_log:=false;	 
	 While do_log =false Loop
          n_date := to_date(:System.Current_Datetime,'DD-MON-YYYY HH24:MI:SS')+0.002; 
          While to_date(:System.Current_Datetime,'DD-MON-YYYY HH24:MI:SS')<n_date Loop
        	null;
         end loop;
	    do_log:=get_connection(un,pw1,cs); 	    
	 End Loop;  

        logout;
     LOGON(un,pw);
-- 	 в это месте говорит ALREADY LOGGED ON. Must logout before changing connections

	 timer_id := FIND_TIMER ('LOAD_TIMER');
   IF Id_Null(Timer_id) THEN
      Timer_id := Create_timer('LOAD_TIMER', 6000, NO_REPEAT);
   ELSE
       SET_TIMER(timer_id, 6000, NO_REPEAT);
   END IF;	 
END;

Функция
FUNCTION GET_CONNECTION ( 
  v_userName IN VARCHAR2 DEFAULT NULL,
  v_password IN VARCHAR2 DEFAULT NULL,
  v_datasource IN VARCHAR2 DEFAULT NULL
) RETURN BOOLEAN IS
  c_attempts CONSTANT INTEGER := 3;
  un VARCHAR2(80);
  pw VARCHAR2(80);
  cn VARCHAR2(80);
  tmpConInfo VARCHAR2(255);
  tmpConHandle EXEC_SQL.ConnType;
  logonSuccessful BOOLEAN := FALSE;
BEGIN 
--	message('get_con') ; pause;  
      un := v_username;
      pw := v_password;
      cn := v_datasource;    
    IF ((un is null) and (pw is null) and (cn is null)) THEN      
      logonSuccessful:=false;
    END IF;
    BEGIN
      tmpConHandle := EXEC_SQL.OPEN_CONNECTION(un, pw, cn);
    EXCEPTION
    WHEN EXEC_SQL.PACKAGE_ERROR THEN     
      logonSuccessful:=false;
    END;
    IF EXEC_SQL.VALID_CONNECTION(tmpConHandle) THEN
      logonSuccessful := TRUE;
      EXEC_SQL.CLOSE_CONNECTION(tmpConHandle);
    END IF;
  IF logonSuccessful THEN
    RETURN TRUE;
  ELSE
    RETURN FALSE;
  END IF;  
END;