2. UPDATE (IN-PLACE) 对应于未修改主键索引列,并且所修改的列长度未发生变化(btr_cur_update_in_place)。注意对于变长的数据类型(e.g varchar),只要数据的实际长度发生变化,都不属于 inplace update(row_upd_changes_field_size_or_external 会返回 true) 原记录的
(4) Analyze data as of an earlierpoint in time by using Oracle Flashback Query (5) Recover from logicalcorruptions using Oracle Flashback features Whena ROLLBACK statement is issued, undo records are used to undo changesthat were made to the database by the uncommitted transaction. During dat...
arbitrarily large) number of changes to our single row of data, but we clearlycan’t record an infinite number of undo records without growing the data filesof the undo tablespace, nor can we record an infinite number of changes in theredo log without constantly adding more...
VERSION_OPERATION :这条记录执行的操作(Insert/Update/Delete)SELECTUNDO_SQLFROMFLASHBACK_TRANSACTION_QUERYWHEREXID='000A000D00000029'; 闪回事务查询。 闪回事务查询有别于闪回查询的特点有以下3个: (1)其正常工作不但需要利用撤销数据,还需要事先启用最小补充日志。 (2)返回的结果不是以前的“旧”数据,而是...
SQL> create table chf.t_xifenfei(a varchar2(4000)); Table created. SQL> insert into chf.t_xifenfei values (lpad('www.xifenfei.com',4000,'a')); 1 row created. SQL> insert into chf.t_xifenfei values (lpad('www.xifenfei.com',4000,'b')); ...
Analyze data as of an earlier point in time by using Oracle Flashback Query 5 使用Oracle Flashback功能从逻辑损坏中恢复 Recover from logical corruptions using Oracle Flashback features When a ROLLBACK statement is issued, undo records are used to undo changes that were made to the database by...
(4) Analyze data as of an earlierpoint in time by using Oracle Flashback Query (5) Recover from logicalcorruptions using Oracle Flashback features Whena ROLLBACK statement is issued, undo records are used to undo changesthat were made to the database by the uncommitted transaction. During dat...
After transactions are completed, the purge system frees the rollback segments in the undo tablespace, the undo tablespace is truncated to its initial size, and the undo tablespace state changes from inactive to empty. Note When an ALTER UNDO TABLESPACE tablespace_name SET INACTIVE statement ...
but in my opinion the single most important feature of Oracle is one that first appeared in version 6: the change vector, a mechanism for describing changes to data blocks, the heart of redo and undo. 一Basic Data Change基础数据改变
permitted to finish, as are any transactions started before those transactions are completed. After transactions are completed, the purge system frees the rollback segments in the undo tablespace, the undo tablespace is truncated to its initial size, and the undo tablespace state changes frominactive...