What is Fast_start_mttr_target?
What is Fast_start_mttr_target?
FAST_START_MTTR_TARGET enables you to specify the number of seconds the database takes to perform crash recovery of a single instance. When specified, FAST_START_MTTR_TARGET is overridden by LOG_CHECKPOINT_INTERVAL .
What happens during Oracle instance recovery?
Instance recovery refers to the case where a surviving instance recovers a failed instance in an Oracle Real Application Clusters database. The goal of crash and instance recovery is to restore the data block changes located in the cache of the dead instance and to close the redo thread that was left open.
How will reduce the checkpoint frequency?
To reduce the checkpoint frequency and optimize runtime performance, you can do the following:
- Size your online redo log files according to the amount of redo your system generates.
- Set the value of the LOG_CHECKPOINT_INTERVAL initialization parameter (in multiples of physical block size) to zero.
What parameter controls how often the database checkpoints and also tries to reduce the time that instance recovery will take?
The FAST_START_MTTR_RECOVERY parameter is used to indicate to the Oracle database how much time to allow for instance recovery. Based on this parameter, the Database Writer process will write to the database data files at a rate that will try to match this target.
What is Archive_lag_target?
ARCHIVE_LAG_TARGET limits the amount of data that can be lost and effectively increases the availability of the standby database by forcing a log switch after the specified amount of time elapses. A 0 value disables the time-based thread advance feature; otherwise, the value represents the number of seconds.
How do I backup my Oracle controls?
You have two options:
- Back up the control file to a binary file (duplicate of existing control file) using the following statement: ALTER DATABASE BACKUP CONTROLFILE TO ‘/oracle/backup/control. bkp’;
- Produce SQL statements that can later be used to re-create your control file: ALTER DATABASE BACKUP CONTROLFILE TO TRACE;
What is complete recovery in Oracle?
Complete recovery involves using redo data or incremental backups combined with a backup of a database, tablespace, or datafile to update it to the most current point in time. It is called complete because Oracle applies all of the redo changes contained in the archived and online logs to the backup.
What is an Oracle checkpoint?
A checkpoint occurs when Oracle moves new or updated blocks (called dirty blocks) from the RAM buffer cache to the database datafiles. A checkpoint keeps the database buffer cache and the database datafiles synchronized.
What is dirty buffer in Oracle?
A dirty buffer is a modified buffer in the database buffer cache that no longer matches the corresponding block on the disk. When DBWR writes dirty buffers to the disk, the status of dirty buffers changes to free buffers.
What is database recovery?
Recovery is the rebuilding of a database or table space after a problem such as media or storage failure, power interruption, or application failure. If you have backed up your database, or individual table spaces, you can rebuild them should they become damaged or corrupted in some way.
What is recovery model in SQL?
A recovery model is a database property that controls how transactions are logged, whether the transaction log requires (and allows) backing up, and what kinds of restore operations are available. Three recovery models exist: simple, full, and bulk-logged.