The following is a list of predefined alarms for database or database partition home page. To the right of each alarm name is the home page component and metric for which the alarm thresholds are defined. If necessary, you can use the Metric Editor to adjust the thresholds that correspond to these alarms to reflect your DB2 database or database partition environment.
|
Alarm |
Home Page Panel |
Component |
|---|---|---|
|
Buffer Pool |
Overall Hit Rate | |
|
Buffer Pool |
Index Hit Rate | |
|
Buffer Pool |
Package Cache Hit Rate | |
|
Buffer Pool |
Package Cache Hit Rate | |
|
Buffer Pool |
Catalog Cache Hit Rate | |
|
Buffer Pool |
Catalog Cache Hit Rate | |
|
Buffer Pool |
Lock List Utilization | |
|
Buffer Pool |
Pct of Thresholds | |
|
Buffer Pool |
Overflows | |
|
Storage |
DMS graph | |
|
Storage |
DMS Utilization | |
|
Storage |
SMS graph | |
|
Storage |
SMS Utilization | |
|
Active Log |
Active Log graph | |
|
Active Log |
Active Log Utilization |
The Buffer Pool Index Hit Rate alarm becomes active when the buffer pool index hit ratio, expressed as a percentage, for a database is low.
When the buffer pool hit rate is high, many of the index and data pages required to satisfy a query are found in a buffer pool. When the buffer pool hit rate is low, I/O is required to load the required pages from external storage.
Certain applications have low buffer hit rates for various reasons. Applications (such as data warehousing applications) that perform frequent table scans of large tables see little buffer pool improvement even with large buffer pools.
The default thresholds are predefined as follows:
Threshold 1—The zero to 69 percent range. This raises a High severity alarm stating, The buffer pool hit ratio is extremely low.
Threshold 2—The 70 to 79 percent range. This raises a Medium severity alarm stating, The buffer pool hit ratio is low.
Threshold 3—The 80 to 89 percent range. This raises a Low severity alarm stating, The buffer pool hit ratio is moderate.
Threshold 4—The 90 to 100 percent range. The buffer pool hit ratio is high. No alarms are raised.
Note: These hit rate thresholds should take into account the normal buffer pool activity incurred by the types of applications your database supports.
The underlying metrics for this alarm can be adjusted to suit your environment by using the Metric Editor.
Access the Buffer Pools drilldown and the I/O Activity tab on the Databases drilldown for buffer pool details and statistics.
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The Buffer Pool Overall Hit Rate alarm becomes active when the buffer pool hit ratio, expressed as a percentage, for a database is low.
When the buffer pool hit rate is high, many of the index and data pages required to satisfy a query are found in a buffer pool. When the buffer pool hit rate is low, I/O is required to load the required pages from external storage.
Certain applications have low buffer hit rates for various reasons. Applications (such as data warehousing applications) that perform frequent table scans of large tables see little buffer pool improvement even with large buffer pools.
The default thresholds are predefined as follows:
Threshold 1—The zero to 69 percent range. This raises the High severity alarm stating, The buffer pool hit ratio is extremely low.
Threshold 2—The 70 to 79 percent range. This raises the Medium severity alarm stating, The buffer pool hit ratio is low.
Threshold 3—The 80 to 89 percent range. This raises the Low severity alarm stating, The buffer pool hit ratio is moderate.
Threshold 4—The 90 to 100 percent range. The buffer pool hit ratio is high. No alarms are raised.
Note: These hit rate thresholds should take into account the normal buffer pool activity incurred by the types of applications your database supports.
The underlying metricsfor this alarm can be adjusted to suit your environment by using the Metric Editor.
Access the Buffer Pool Summary drilldown and the I/O Activity tab on the Databases drilldown for buffer pool details and statistics.
The Catalog Cache Hit Rate alarm becomes active when the catalog cache hit rate, expressed as a percentage, is low.
The catalog cache is memory that temporarily stores table descriptors—information about tables, views, and aliases in a condensed internal format—found in the database catalog. During SQL statement compilation and dynamic SQL processing, the catalog cache is searched first for descriptors of objects referenced in the SQL statement. If these descriptors are available in cache, the transaction uses descriptor information in cache and avoids having to access the database catalog.
High catalog cache hit rates indicate that the I/O required to compile SQL statements is minimal. When the hit rate is low, catalog cache is not being used efficiently.
The underlying metricsfor this alarm can be adjusted to suit your environment by using the Metric Editor.
Consider increasing the size of the catalog cache using the CATALOGCACHE_SZ database configuration parameter.
Access the Databases drilldown. The Caching tab provides statistics about catalog caching on the database.
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