ORA-01861: literal does not match format string 错误！

SQL> CREATE OR REPLACE PROCEDURE "SGREPORTS"."METRIC_DATA_ROLLUP" (rollup_time DATE)
2 AS
3 default_time DATE := rollup_time;
4 BEGIN
5 begin
6 EXECUTE IMMEDIATE ('ALTER SESSION SET TIME_ZONE = DBTIMEZONE');
7 execute immediate ('alter session set nls_date_format=''YYYY-MM-DD HH24:MI:SS''');
8 execute immediate ('alter session set nls_language=american');
9 IF rollup_time IS NULL
10 THEN
11 default_time := TRUNC (SYSDATE, 'HH24') - 1 / 24;
12 ELSE
13 default_time := TRUNC (default_time, 'HH24');
14 END IF;
15 DELETE FROM metric_data_hourly
16 WHERE datetime = cast(TO_TIMESTAMP_TZ(default_time, 'YYYY-MM-DD HH24:MI:SS') AS TIMESTAMP WITH LO
17 EXCEPTION
18 WHEN OTHERS
19 THEN
20 dbms_output.put_line('syntax error:'||SQLerrm);
21 end;
22 begin
23 INSERT INTO metric_data_hourly SELECT /*+INDEX(A1,PK_METRIC_DATA_HOURLY)*/ *
24 FROM sgreports.metric_data_hourly@RPTS.NILE002A_ZONE01.EAST A1
25 WHERE datetime between cast(TO_TIMESTAMP_TZ(default_time, 'YYYY-MM-DD HH24:MI:SS') AS TIMESTAMP W
26 and cast(TO_TIMESTAMP_TZ(default_time, 'YYYY-MM-DD HH24:MI:SS')+ 3599 / 86400 AS TIMESTAMP WITH LOCA
27 EXCEPTION
28 WHEN OTHERS
29 THEN
30 dbms_output.put_line(SQLerrm);
31 END;
32 end;
33 /

过程已创建。

SQL> exec metric_data_rollup ('2009-04-11 21:00:00');
BEGIN metric_data_rollup ('2009-04-11 21:00:00'); END;

*
第 1 行出现错误:
ORA-01861: literal does not match format string
ORA-06512: at line 1

SQL> alter session set nls_date_format='YYYY-MM-DD HH24:MI:SS';

会话已更改。

SQL> alter session set nls_language=american;

Session altered.

SQL> exec metric_data_rollup ('2009-04-11 21:00:00');