ARCHIVE LOG

Purpose

Starts or stops automatic archiving of online redo log files, manually (explicitly) archives specified redo log files, or displays information about redo log files.

Syntax

ARCHIVE LOG {LIST|STOP}|{START|NEXT|ALL|integer} [TO destination]

Terms and Clauses

Refer to the following list for a description of each term or clause:

LIST

Requests a display that shows the range of redo log files to be archived, the current log file group's sequence number, and the current archive destination (specified by either the optional command text or by the initialization parameter LOG_ARCHIVE_DEST).

If you are using both ARCHIVELOG mode and automatic archiving, the display might appear like:

SQL> ARCHIVE LOG LIST

Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            /vobs/oracle/dbs/arch
Oldest online log sequence     221
Next log sequence to archive   222
Current log sequence           222

Since the log sequence number of the current log group and the next log group to archive are the same, automatic archival has archived all log groups up to the current one.

If you are using ARCHIVELOG but have disabled automatic archiving, the last three lines might look like:

Oldest online log sequence            222
Next log sequence to archive          222
Current log sequence                  225

If you are using NOARCHIVELOG mode, the "next log sequence to archive" line is suppressed.

The log sequence increments every time the Log Writer begins to write to another redo log file group; it does not indicate the number of logs being used. Every time an online redo log file group is reused, the contents are assigned a new log sequence number.

STOP

Disables automatic archival. If the instance is still in ARCHIVELOG mode and all redo log file groups fill, database operation is suspended until a redo log file is archived (for example, until you enter the command ARCHIVE LOG NEXT or ARCHIVE LOG ALL).

START

Enables automatic archiving. Starts the background process ARCH, which performs automatic archiving as required. If ARCH is started and a filename is supplied, the filename becomes the new default archive destination.

ARCH automatically starts on instance startup if the initialization parameter LOG_ARCHIVE_START is set to TRUE.

NEXT

Manually archives the next online redo log file group that has been filled, but not yet archived.

ALL

Manually archives all filled, but not yet archived, online log file groups.

integer

Causes archival of the online redo log file group with log sequence number n. You can specify any redo log file group that is still online. An error occurs if the log file cannot be found online or the sequence number is not valid. This option can be used to rearchive a log file group.

destination

Specifies the destination device or directory in an operating system. Specification of archive destination devices is installation-specific; see your platform-specific Oracle documentation for examples of specifying archive destinations. On many operating systems, multiple log files can be spooled to the same tape.

If not specified in the command line, the archive destination is derived from the initialization parameter LOG_ARCHIVE_DEST. The command ARCHIVE LOG START destination causes the specified device or directory to become the new default archive destination for all future automatic or manual archives. A destination specified with any other option is a temporary destination that is in effect only for the current (manual) archive. It does not change the default archive destination for subsequent automatic archives.

For information about specifying archive destinations, see your platform-specific Oracle documentation.

Usage Notes

You must be connected to an open Oracle database as SYSOPER, or SYSDBA. For information about connecting to the database, see the CONNECT command.

If an online redo log file group fills and none are available for reuse, database operation is suspended. The condition can be resolved by archiving a log file group.

For information about specifying archive destinations, see your platform-specific Oracle documentation.

Examples

To start up the archiver process and begin automatic archiving, using the archive destination specified in LOG_ARCHIVE_DEST, enter

SQL> ARCHIVE LOG START

To stop automatic archiving, enter

SQL> ARCHIVE LOG STOP 

To archive the log file group with the sequence number 1001 to the destination specified, enter

SQL> ARCHIVE LOG 1001 '/vobs/oracle/dbs/arch' 

'arch' specifies the prefix of the filename on the destination device; the remainder of the filename is dependent on the initialization parameter LOG_ARCHIVE_FORMAT, which specifies the filename format for archived redo log files.