Databases Reference
In-Depth Information
Chapter 5
Managing Control Files,
Online Redo Logs, and Archiving
An Oracle database consists of three types of mandatory files: data files, control files, and online redo logs.
Chapter 4 focused on tablespaces and data files. This chapter looks at managing control files and online redo logs
and implementing archiving (of the online redo logs). The first part of the chapter discusses typical control file
maintenance tasks, such adding, moving, and removing control files. The middle part of the chapter examines DBA
activities related to online redo log files, such as renaming, adding, dropping, and relocating these critical files.
Finally, the architectural aspects of enabling and implementing archiving are covered.
Managing Control Files
A control file is a small binary file that stores the following types of information:
•
Database name
•
Names and locations of data files
•
Names and locations of online redo log files
•
Current online redo log sequence number
•
Checkpoint information
•
Names and locations of RMAN backup files (if using)
You can query much of the information stored in the control file from data dictionary views. This example
displays the types of information stored in the control file by querying
V$CONTROLFILE_RECORD_SECTION
:
SQL> select distinct type from v$controlfile_record_section;
Here is a partial listing of the output:
TYPE
----------------------------
FILENAME
TABLESPACE
RMAN CONFIGURATION
BACKUP CORRUPTION
PROXY COPY
