Performing Oracle User-Managed Database Recoveries - OCP: Oracle Database 12c Administrator Certified Professional - page 85

exeRCiSe 2.3 (continued)

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Performing Other Types of Recoveries

You will need to be prepared for other types of user-managed recoveries when taking your
OCP exam or just in the course of managing your Oracle Database. In the following sections,
we will talk about the following types of user-managed recoveries:

Loss of a tempfile

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Loss of an online redo log group

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Loss of the control file

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Loss of the password file

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Loss of everything

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Recovering from the Loss of a Tempfile

Tempfiles are used with temporary tablespaces. As discussed in Chapter 1, you do not need to
back up a tempfile. Because of its temporary nature, the contents of a tempfile are not needed
during a recovery. You will need to recreate the tempfile after any recovery that includes the
temporary tablespace. This is done by using the ALTER TABLESPACE ADD TEMPFILE command
as shown in this example, where we add a tempfile to the TEMP tablespace:

ALTER TABLESPACE TEMP ADD TEMPFILE '/oracle01/oradata/orcl/temp01.dbf'
SIZE 200m REUSE AUTOEXTEND ON;

Recovering from the Loss of an Online Redo Log Group

Loss of the online redo logs comes in four different flavors:
■ Loss of a redo log file group member
■ Loss of an inactive online redo log group
■ Loss of an active but not current online redo log group
■ Loss of the current online redo log group
Any loss of an entire online redo log group makes for a very bad day. Loss of the last
two categories (loss of an active or current online redo log) is often a disaster.