Background Checkpoint (BGChkpntRate)
The BGChkpntRate parameter reports the number of checkpoints per hour over the previous interval. If checkpoints are occurring too frequently then run time performance can be reduced and wait states caused. If checkpoints are too widely spaced in time then recovery time may be increased. Normally checkpoints only happen when a redo log switch occurs or the instance is subjected to a shutdown normal.
Recommendations
Use the following approaches:
- To reduce the number of checkpoints, increase the init.ora log_checkpoint_interval parameter. If the log_checkpoint_interval size is greater than the redo log file size, checkpoints occur only when switching logs. If it is set to a small value, checkpoints occur often and instance recovery is fast.
- If the Log Writer process (LGWR) performance is poor during checkpoints, enable the Checkpoint process (CKPT).
- CKPT updates file headers when a checkpoint occurs, leaving the LGWR free to write redo entries.
- To enable CKPT, set the value of the init.ora checkpoint_processes parameter to TRUE. Before enabling CKPT, verify whether your operating system can support an additional process; you may need to increase the value of the init.ora processes parameter.
Thresholds for alarms and warnings
Item | Default threshold | State |
|---|---|---|
Border range | undefined | undefined |
Alarm1 range | 3-50 | WARN |
Alarm2 range | undefined | undefined |
BMC PATROL properties
Attribute | Default value |
|---|---|
Application class | ORACLE_PERFORMANCE |
Command type | Not applicable |
Platform | All |
Icon style | Graph |
Unit | Checkpoints per hour |
Border range | Undefined |
Alarm1 range | 3-50 WARN |
Alarm2 range | Undefined |
Scheduling(poll time) | Poll time of collector |
Active at installation | Yes |
Parameter type | Consumer |
Value set by | CollPerformance |
BMC ProactiveNet Performance Management properties
Property | Default value |
|---|---|
| Monitor type | Oracle Database Performance |
| Key Performance Indicator | No |
| Monitor for abnormalities | Yes |
| Graph by default | No |
| Availability | No |
| Response time | No |
| Normal distribution | Yes |
| Statistical | Yes |
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