Databases Reference
In-Depth Information
The last query of this recipe helps us to obtain
RECOVERY_ESTIMATED_IOS
. This is an
estimate of the number of data blocks to be processed during recovery.
ESTIMATED_MTTR
indicates the estimated recovery time, based on the current system load.
TARGET_MTTR
is based on the value of the
FAST_START_MTTR_TARGET
parameter and on the system
performance and limitations.
LOG_FILE_SIZE_REDO_BLKS
is the number of redo blocks
required to make sure that a log switch doesn't occur before the checkpoint completes.
The value for
LOG_CHKPT_INTERVAL_REDO_BLKS
and
LOG_CHKPT_TIMEOUT_REDO_BLKS
indicates the number of redo blocks that will be processed during recovery to satisfy the
LOG_CHECKPOINT_INTERVAL
and
LOG_CHECKPOINT_TIMEOUT
parameters, respectively.
See also
F
The
Tuning redo logs
recipe that follows
Tuning redo logs
In this recipe, we will see how to monitor redo logs.
How to do it...
The following steps will demonstrate monitoring of redo logs:
1.
Connect to the database as
SYSDBA
:
CONNECT / AS SYSDBA
2.
Verify possible problems by inspecting the
V$SYSTEM_EVENT
dynamic
performance view:
SELECT EVENT, TOTAL_WAITS, TIME_WAITED FROM V$SYSTEM_EVENT
WHERE EVENT LIKE 'log file%';
3. Query the data dictionary about the redo log files:
COL MEMBER FOR A40
SELECT * FROM V$LOGFILE;
CLEAR COL
4.
Query the data dictionary about redo log details:
SELECT * FROM V$LOG;
5.
Query the historical log switch data:
SELECT * FROM V$LOG_HISTORY ORDER BY RECID;
