如何启动block change tracking

 

  block change tracking记录上一次备份变化的数据块,并将这些信息记录在日志文件中,rman增量备份的时候就直接扫描这些日志文件
去判断需要备份的增量数据块,这极大提高了备份的性能.

1.尝试启用block change tracking
SQL> alter database enable block change tracking;
alter database enable block change tracking
*
ERROR at line 1:
ORA-19773: must specify change tracking file name

2.设置 db_create_file_dest
SQL> alter system set DB_CREATE_FILE_DEST='d:\oracle' scope=both;

System altered.

3.再次执行
SQL> alter database enable block change tracking;

Database altered.

 

4.查看变化的数据块
SQL> column status format a8;
SQL> column filename format a50;
SQL> column bytes format 99999999;
SQL> select status,filename,bytes from v$block_change_tracking;

STATUS   FILENAME                                               BYTES
-------- -------------------------------------------------- ---------
ENABLED  D:\ORACLE\HXL\CHANGETRACKING\O1_MF_89RS6R01_.CHG    11599872

5.停止block change tracking
alter database disable block change tracking;

备注:
若是没有设置DB_CREATE_FILE_DEST,也可以使用如下命令指定日志文件
alter database enable block change tracking usingfile 'd:\rman\trace.log';

 

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