What is the difference between undo and redo? What is the difference between undo and redo?

What is the difference between undo and redo?

The undo perform is used to reverse a mistake, similar to deleting the fallacious phrase in a sentence. The redo perform restores any actions that had been beforehand undone utilizing an undo. For instance, when you typed a phrase, and then deleted it utilizing an undo, the redo perform would restore the phrase you deleted (“undid”).

What is redo log in MySQL?

The redo log is a disk-based knowledge construction used throughout crash restoration to appropriate knowledge written by incomplete transactions. By default, the redo log is bodily represented on disk by two information named ib_logfile0 and ib_logfile1 . MySQL writes to the redo log information in a round style.

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The place is Oracle redo log file?

The redo log information are initially specified inside the CREATE DATABASE command. CREATE DATABASE . . . LOGFILE ‘/t02/oradata/MYDB/redo1.

How do I view MySQL transaction logs?

In case you’re utilizing MySql on Home windows, there’s a file situated in C:Program FilesMySQLMySQL Server 5.0data (assuming a C: drive for the set up goal and MySql model 5.0), that is known as %COMPUTERNAME%. log that comprises the instructions which were executed.

How do I discover my archive log checklist?

The next instructions can be utilized to find the Oracle archive logs:

  1. Difficulty the archive log checklist command: SQL> archive log checklist.
  2. Difficulty the present parameter command: SQL> present parameter db_recovery_file_dest.
  3. Question the v$archive_dest view: SQL> choose dest_name, standing, vacation spot from v$archive_dest;

How do I modify archive log mode?

Process

  1. Log in as person oracle and enter the following instructions: $ export ORACLE_SID=
  2. To allow ARCHIVELOG mode standing, enter the following SQL instructions: SQL> Shutdown SQL> Startup mount SQL> Alter database archivelog; SQL> alter database open;
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How do I disable archive log?

Disabling ARCHIVELOG mode

  1. Log in as OS person, oracle and enter the following instructions: $ export ORACLE_SID=
  2. To allow ARCHIVELOG mode standing, enter the following SQL instructions: SQL> Shutdown SQL> Startup mount SQL> Alter database noarchivelog; SQL> alter database open;

How do I modify the archive log in Oracle?

Utilizing EM to Change the Database Archiving Mode To alter the archiving mode from NOARCHIVELOG to ARCHIVELOG utilizing Enterprise Supervisor, comply with the steps under. Notice: Oracle Enterprise Supervisor 9.2 was utilized in the examples. 1. Choose START > Packages > Oracle > OraHome92 > Enterprise Supervisor Console.

How do I learn a redo log in Oracle?

LogMiner retrieves info from these redo log information and returns it by means of the V$LOGMNR_CONTENTS view. You’ll be able to then use SQL to question the V$LOGMNR_CONTENTS view, as you’ll another view. Every choose operation that you just carry out towards the V$LOGMNR_CONTENTS view causes the redo log information to be learn sequentially.

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What is Noarchivelog mode?

9.2. In NOARCHIVELOG mode, the stuffed redo log teams that turn out to be inactive will be reused. In ARCHIVELOG mode, stuffed teams of redo logs are archived. This mode protects the database from each occasion and media failure, however could require extra {hardware} assets.

How is block change monitoring enabled?

Once you allow block change monitoring in Oracle 11g, Oracle tracks the bodily location of all database modifications for incremental backups. RMAN mechanically makes use of the change monitoring file to find out which blocks should be learn throughout an incremental backup, and immediately accesses these blocks to again them up.

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