Initialization Parameters, 48 of 188

FAST_START_IO_TARGET

Parameter type:
Integer

Parameter class:
Dynamic. Scope = ALTER SESSION, ALTER SYSTEM.

Default value:
All the buffers in the cache

Range of values:
1000 to all buffers in the cache. A setting of 0 disables limiting recovery I/Os.

Oracle Parallel Server:
Multiple instances can have different values, and you can change the values at runtime.

FAST_START_IO_TARGET (available only with the Oracle Enterprise Edition) specifies the number of I/Os that should be needed during crash or instance recovery. It gives you more precise control over the duration of recovery than DB_BLOCK_MAX_DIRTY_TARGET.
When you set this parameter, DBWn writes dirty buffers out more aggressively, so that the number of blocks that must be processed during recovery stays below the value specified in the parameter. However, this parameter does not impose a hard limit on the number of recovery I/Os. Under transient workload situations, the number of I/Os needed during recovery may be greater than the value specified in this parameter. In such situations, DBWn will not slow down database activity.

Smaller values for this parameter result in faster recovery times. This improvement in recovery performance is achieved at the expense of additional writing activity during normal processing.
Setting this parameter to 0 disables fast-start checkpointing, which is the mechanism that limits the number of I/Os that need to be performed during recovery. All other writing activity is unaffected.

Note: Recovery I/O can also be limited by setting the LOG_CHECKPOINT_TIMEOUT or LOG_CHECKPOINT_INTERVAL parameter or by the size specified for the smallest redo log. For information on which mechanism is controlling checkpointing behavior, query the V$INSTANCE_RECOVERY view.

See Also:

Oracle8i Designing and Tuning for Performance for more information on setting this parameter.

Oracle8i Backup and Recovery Guide and V$INSTANCE_RECOVERY for information on fast-start checkpointing.

Parameter type:	Integer
Parameter class:	Dynamic. Scope = `ALTER` `SESSION`, `ALTER` `SYSTEM.`
Default value:	All the buffers in the cache
Range of values:	1000 to all buffers in the cache. A setting of 0 disables limiting recovery I/Os.
Oracle Parallel Server:	Multiple instances can have different values, and you can change the values at runtime.
`FAST_START_IO_TARGET` (available only with the Oracle Enterprise Edition) specifies the number of I/Os that should be needed during crash or instance recovery. It gives you more precise control over the duration of recovery than `DB_BLOCK_MAX_DIRTY_TARGET`. When you set this parameter, `DBW``n` writes dirty buffers out more aggressively, so that the number of blocks that must be processed during recovery stays below the value specified in the parameter. However, this parameter does not impose a hard limit on the number of recovery I/Os. Under transient workload situations, the number of I/Os needed during recovery may be greater than the value specified in this parameter. In such situations, `DBW``n` will not slow down database activity.
Smaller values for this parameter result in faster recovery times. This improvement in recovery performance is achieved at the expense of additional writing activity during normal processing. Setting this parameter to 0 disables fast-start checkpointing, which is the mechanism that limits the number of I/Os that need to be performed during recovery. All other writing activity is unaffected.
Note: Recovery I/O can also be limited by setting the `LOG_CHECKPOINT_TIMEOUT` or `LOG_CHECKPOINT_INTERVAL` parameter or by the size specified for the smallest redo log. For information on which mechanism is controlling checkpointing behavior, query the `V$INSTANCE_RECOVERY` view.
See Also: Oracle8i Designing and Tuning for Performance for more information on setting this parameter. Oracle8i Backup and Recovery Guide and V$INSTANCE_RECOVERY for information on fast-start checkpointing.