V$LOG

V$LOG displays log file information from the control file.

Column Datatype Description

GROUP#               NUMBER          Log group number
THREAD#              NUMBER          Log thread number
SEQUENCE#            NUMBER          Log sequence number
BYTES                NUMBER          Size of the log (in bytes)
MEMBERS              NUMBER          Number of members in the log group
ARCHIVED             VARCHAR2(3)     Archive status YES or NO)
STATUS               VARCHAR2(16)    Log status:

UNUSED- Online redo log has never been written to. This is the state of a redo log that was just added, or just after a RESETLOGS, when it is not the current redo log.
CURRENT- Current redo log. This implies that the redo log is active. The redo log could be open or closed.
ACTIVE- Log is active but is not the current log. It is needed for crash recovery. It may be in use for block recovery. It may or may not be archived.
CLEARING- Log is being re-created as an empty log after an ALTER DATABASE CLEAR LOGFILE|statement. After the log is cleared, the status changes to UNUSED.
CLEARING_CURRENT- Current log is being cleared of a closed thread. The log can stay in this status if there is some failure in the switch such as an I/O error writing the new log header.
INACTIVE- Log is no longer needed for instance recovery. It may be in use for media recovery. It might or might not be archived.

FIRST_CHANGE# NUMBER Lowest system change number (SCN) in the log
FIRST_TIME DATE Time of the first SCN in the log

V$LOGFILE

This view contains information about redo log files.

Column Datatype Description

GROUP# NUMBER Redo log group identifier number
STATUS VARCHAR2(7) Status of the log member:

INVALID- File is inaccessible
STALE - File's contents are incomplete
DELETED- File is no longer used
NULL - File is in use

TYPE VARCHAR2(7) Type of the logfile:

ONLINE
STANDBY

MEMBER                VARCHAR2(513) Redo log member name
IS_RECOVERY_DEST_FILE VARCHAR2(3)    Indicates whether the file was created in the flash recovery area (YES)
                                     or not (NO)

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v$log详解

V$LOG

V$LOGFILE

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