oracle中truncate、drop等ddl语句都产生redo 和undo信息
sys@ORCL> select m.value,s.name from v$mystat m join v$statname s on m.statistic#=s.statistic# where s.name in ('undo change vector size', 'redo size');
VALUE NAME
---------- ----------------------------------------------------------------
0 redo size
0 undo change vector size
sys@ORCL> truncate table hn.emp;
Table truncated.
sys@ORCL> select * from hn.emp;
no rows selected
sys@ORCL> select m.value,s.name from v$mystat m join v$statname s on m.statistic#=s.statistic# where s.name in ('undo change vector size', 'redo size');
VALUE NAME
---------- ----------------------------------------------------------------
7028 redo size
2108 undo change vector size
sys@ORCL>
证明：truncate产生redo和undo信息
sys@ORCL> select m.value,s.name from v$mystat m join v$statname s on m.statistic#=s.statistic# where s.name in ('undo change vector size', 'redo size');
VALUE NAME
---------- ----------------------------------------------------------------
7028 redo size
2108 undo change vector size
sys@ORCL> drop table hn.emp;
Table dropped.
sys@ORCL> select m.value,s.name from v$mystat m join v$statname s on m.statistic#=s.statistic# where s.name in ('undo change vector size', 'redo size');
VALUE NAME
---------- ----------------------------------------------------------------
14080 redo size
4172 undo change vector size
证明：drop语句也产生redo和undo信息
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