The Sort Overflows alarm becomes active when the percentage of sort at the database or partition exceeds the overflow threshold limits. Sort heap is controlled by the SHEAPTHRES database manager configuration parameter, which sets the sort heap threshold for the entire instance and by the SORTHEAP database configuration parameter, which sets the sort heap size. Sort overflows are sorts that run out of sort heap and require disk space for temporary storage.
The thresholds are predefined as follows:
Threshold 1—The zero to 69 percent range. The percent of sort overflows is very low. No alarms are raised.
Threshold 2—The 70 to 79 percent range. This raises a Low severity alarm stating, The percent of sort overflows is moderate.
Threshold 3—The 80 to 89 percent range. This raises a Medium severity alarm stating, The percent of sort overflows is high.
Threshold 4—The 90 to 100 percent range. This raises a High severity alarm stating, The percent of sort overflows is very high.
The underlying metricsfor this alarm can be adjusted to suit your environment by using the Metric Editor.
If the percentage of overflowed sorts is high, increase the sort heap.
If there were any post-threshold sorts, increase the SHEAPTHRES configuration parameters. To determine if there were any post threshold sorts, click the Overflows component to open the Databases drilldown. This drilldown provides details about all the active databases in the DB2 instance. You can select any database to view details about that database, including sort activity and sort heap usage statistics.