What are Oracle archive logs?

Asked By: Vanuza Lutscher | Last Updated: 28th February, 2020
Category: technology and computing databases
4/5 (166 Views . 37 Votes)
Oracle 12c's archive log files are simply copies of redo log files. They're no different from redo log files except that they get a new name when they're created. Most archive log files have the extension .

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Moreover, what is archive log file in Oracle?

Oracle Database lets you save filled groups of redo log files to one or more offline destinations, known collectively as the archived redo log, or more simply the archive log. The process of turning redo log files into archived redo log files is called archiving.

Secondly, what happens when archive log is full in Oracle? What happens if a archive log destination is filled up in oracle. This is a common problem Oracle DBA's usually face. log destination disk space becomes full, the automatic archiving will stop. Cause: The archiver process received an error while trying to archive a redo log.

Also question is, where are Oracle archive logs stored?

To get started, from the last article, remember that Oracle placed archive logs in a default directory of $ORACLE_HOME/dbs and, if flash recovery was enabled during installation, in the USE_DB_RECOVERY_FILE_DEST, which equated to the init. ora parameter db_recovery_file_dest.

What is the difference between redo log and archive log?

Archive logs are archived redo(online) log files. In redo log files are all changes that happened to your data. If your database is in archivelog mode, than redo logs can't be overwritten, they are archived in some other location when they are full. Redo and archive logs are used in various database recovery scenarios.

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How do I know if my archive log is full?

The following commands can be used to locate the Oracle archive logs:
  1. Issue the archive log list command: SQL> archive log list.
  2. Issue the show parameter command: SQL> show parameter db_recovery_file_dest.
  3. Query the v$archive_dest view: SQL> select dest_name, status, destination from v$archive_dest;

How do I view archive log mode?

Checking ARCHIVELOG mode status
  1. Log in as OS user oracle and enter the following commands: $ export ORACLE_SID=<MYDB> where <MYDB> is the name of the database $ sqlplus /nolog SQL> connect / as sysdba.
  2. To check the ARCHIVELOG mode status, enter the following SQL command: SQL> archive log list;

What is archive log mode?

ARCHIVELOG mode is a mode that you can put the database in for creating a backup of all transactions that have occurred in the database so that you can recover to any point in time. NOARCHIVELOG mode is basically the absence of ARCHIVELOG mode and has the disadvantage of not being able to recover to any point in time.

What archive means?

A. The Gmail app for Android gives its users two choices for discarding a new message: archive or delete. The Archive action removes the message from view in the inbox and puts it in the All Mail area, in case you ever need it again.

How do I change the archive log destination?


Change Archivelog Destination In Oracle
  1. Description:-
  2. Step:-1 Check archivelog location before change.
  3. Check Current Archivelog Location:
  4. SQL> archive log list. Database log mode Archive Mode.
  5. Step:-2 Change archivelog location.
  6. Note:- 1st set the FRA value before changing.
  7. Step:-3 Check the status of archivelog location.
  8. SQL> archive log list.

How do I read a redo log in Oracle?

LogMiner retrieves information from those redo log files and returns it through the V$LOGMNR_CONTENTS view. You can then use SQL to query the V$LOGMNR_CONTENTS view, as you would any other view. Each select operation that you perform against the V$LOGMNR_CONTENTS view causes the redo log files to be read sequentially.

What is password file in Oracle?

Oracle password file stores passwords for users with administrative privileges. Any OS user under dba group, can login as SYSDBA. Password file for an Oracle database is called a database password file, and the password file for Oracle ASM is called an Oracle ASM password file.

What is the difference between Archivelog mode and Noarchivelog mode?

ARCHIVELOG mode is a mode that you can put the database in for creating a backup of all transactions that have occurred in the database so that you can recover to any point in time. NOARCHIVELOG mode is basically the absence of ARCHIVELOG mode and has the disadvantage of not being able to recover to any point in time.

How do I delete old archive logs in RMAN?

In order to delete them you can do: RMAN>crosscheck archivelog all; RMAN>delete noprompt expired archivelog all; , you can also include the delete input clause when you back them up, and they will be deleted after they have been backed up (it is up to you).

What is redo logs in Oracle?


Redo Logs consist of two or more pre-allocated files that store all changes made to the database as they occur. Every instance of an Oracle Database has associated online redo logs to protect the database in case of an instance failure. Redo log files are filled with redo records.

How do I list archive logs in RMAN?

RMAN List Command
  1. Database. The LIST command allows the backup data to be listed in the RMAN utility.
  2. Archive Logs. To list all archive logs use: RMAN> LIST ARCHIVELOG ALL;
  3. Backup sets. To list the contents of an individual backup set use: RMAN> LIST BACKUPSET <key>;
  4. Datafile Image Copies.
  5. Controlfile Image Copies.
  6. Tablespaces.
  7. Incarnations.

How do I add database to Archivelog mode?

Putting the database in ARCHIVELOG Mode
Once you have shutdown the database, you will start the database in mount mode with the startup mount command. Then put the database in ARCHIVELOG mode, and finally open the database.

What is log sequence number in Oracle?

log sequence number. A number that uniquely identifies a set of redo records in a redo log file. When Oracle fills one online redo log file and switches to a different one, Oracle automatically assigns the new file a log sequence number.

How do I turn off archive?

Disable an archive mailbox
  1. Go to Recipients > Mailboxes.
  2. Select a mailbox.
  3. In the details pane, under In-Place Archive, click Disable. Note: You can also bulk-disable archives by selecting multiple mailboxes (use the Shift or Ctrl keys). After selecting multiple mailboxes, in the details pane, click More options.

How do you change from Noarchivelog mode to Archivelog mode?


Step to change database from Archivelog mode to Noarchivelog mode
  1. Login by OS User (For windows as Administrator)
  2. Set ORACLE_SID to connect to required database.
  3. Login to Oracle by SYS as SYSDBA.
  4. Confirm connected database.
  5. Check current log_mode i.e. (Archivelog or Noarchivelog) of database (Before change) {output should be ARCHIVELOG}.
  6. Check current archive status.
  7. Shutdown database.

What is Db_recovery_file_dest?

DB_RECOVERY_FILE_DEST specifies the default location for the flash recovery area. The flash recovery area contains multiplexed copies of current control files and online redo logs, as well as archived redo logs, flashback logs, and RMAN backups.

How do Sessions communicate with the database?

When a three-tier session broker application uses server sessions to communicate with the database, clients require a client session to write to the database. Similarly, when you implement a session broker, the client requires a client session broker to write to the database.