oracle SMON_SCN_TIME(2)

此时SMON_SCN_TIME中的信息如下:

19:45:11 SQL> select * from (select * from smon_scn_time order by time_dp desc)

where rownum <5;

    THREAD    TIME_MP TIME_DP                SCN_WRP    SCN_BAS
---------- ---------- ------------------- ---------- ----------
         1 1134992658 2005-12-19 19:44:18         25      92565
         1 1134992351 2005-12-19 19:39:11         25      92463
         1 1134992042 2005-12-19 19:34:04         25      92256
         1 1134991731 2005-12-19 19:28:53         25      92149

在Oracle10g中，SMON_SCN_TIME表每6秒被更新一次。所以这个Flashback时间被缩小为6秒。

[oracle@danaly ~]$ sqlplus eygle/eygle

SQL*Plus: Release 10.2.0.1.0 - Production on Mon Dec 19 19:37:19 2005

Copyright (c) 1982, 2005, Oracle. All rights reserved.

Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning, Oracle Label Security, OLAP and Data Mining Scoring Engine options

19:37:22 SQL> col myscn for 9999999999999999
19:37:22 SQL> variable myscn number;
19:37:22 SQL> create table eygle (c1 number);

Table created.

19:37:22 SQL> exec :myscn := dbms_flashback.get_system_change_number();

PL/SQL procedure successfully completed.

19:37:22 SQL> print myscn;

            MYSCN
-----------------
      16011230122

19:37:22 SQL> insert into eygle values(1);

1 row created.

19:37:22 SQL> commit;

Commit complete.

19:37:22 SQL> exec :myscn := dbms_flashback.get_system_change_number();

PL/SQL procedure successfully completed.

19:37:22 SQL> print myscn;

            MYSCN
-----------------
      16011230124

19:37:22 SQL> select * from eygle as of scn(:myscn);
select * from eygle as of scn(:myscn)
              *
ERROR at line 1:
ORA-01466: unable to read data - table definition has changed

19:37:22 SQL> select scn_to_timestamp(16011230124) from dual;

SCN_TO_TIMESTAMP(16011230124)
---------------------------------------------------------------------------

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