The dba startup-mounts the database and issues the flashback database command

Chapter 3 ■ Files

■Caution i’ll say this from time to time throughout the book: please bear in mind that commands that set parameters,

SYS@ORA12CR1> alter database disable block change tracking; Database altered.

Note that this command will erase the block change-tracking file. It does not just disable the feature—it removes the file as well.

permit you to erase a file that has been opened by a previous process (for example, the session process that created the

file). this is harmless; you just need to remove the file yourself later.

The FLASHBACK DATABASE command was introduced to speed up the otherwise slow process of point-in-time database recovery. It can be used in place of a full database restore and a rolling forward using archive logs, and it is primarily designed to speed up the recovery from an “accident.” For example, let’s take a look at what a DBA might do to recover from an accidentally dropped schema, in which the right schema was dropped, just in the wrong database (it was meant to be dropped in the test environment). The DBA immediately recognizes the mistake he has made and shuts down the database right away. Now what?

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3. The DBA would restore all archive redo logs generated since the backup that were not available on the system.

4. Using the archive redo logs (and possibly information in the online redo logs), the DBA would roll the database forward and stop rolling forward at a point in time just before the erroneous DROP USER command. Steps 3 and 4 in this list would typically be initiated with RMAN via RECOVER DATABASE UNTIL <point in time>.

2. The DBA startup-mounts the database and issues the flashback database command, using either an SCN (the Oracle internal clock), a restore point (which is a pointer to an SCN), or a timestamp (wall clock time), which would be accurate to within a couple of seconds.

3. The DBA opens the database with resetlogs.

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