Question about redo size in dump file and view

I have a question about redo size generated by insert statement.

Here I want to get redo size of insert/update statement, but the size from redo dump is different from view.

Below is my test case.

1. create test table create table t4 ( a number) tablespace users;
2. insert into one row alter system switch logfile; insert into t4 values (1); commit; alter system switch logfile;
3. dump redo file alter system dump logfile 'C:\APP\LCM\ORADATA\ORCL\REDO03.LOG'
4. get redo size from one session SELECT n.name, s.value FROM v$sesstat s, v$statname n WHERE s.statistic# = n.statistic# AND n.name = 'redo size' and s.sid = 139; NAME VALUE

   ---

   ---

   redo size 0
5. in same session, run insert statement insert into t4 values (1); commit;
6. get redo size of the session in step 5/6 from another session SELECT n.name, s.value FROM v$sesstat s, v$statname n WHERE s.statistic# = n.statistic# AND n.name = 'redo size' and s.sid = 139; NAME VALUE

   ---

   ---

   redo size 140 redo size for lost write detection 0
7. get length of redo in step 4. The length is 488. REDO RECORD - Thread:1 RBA: 0x000142.00000002.0010 LEN: 0x01e8 VLD: 0x0d SCN: 0x0000.004cdff3 SUBSCN: 1 06/07/2009 18:59:50
8. conclusion, the length from redo dump is different from view.

Thanks at first
Jacky Received on Sun Jun 07 2009 - 06:38:49 CDT