| Measurement |
Description |
Measurement
Unit |
Interpretation |
| Sort_heap_allocated
|
The sum of sort heap space allocated for all sorts in all active databases in the database manager |
Pages
|
Normal memory estimates do not include sort heap space. If excessive sorting is occurring, the extra memory used for the sort heap should be added to the base memory requirements for running the database manager. Generally, the larger the sort heap, the more efficient the sort. Appropriate use of indexes can reduce the amount of sorting required. You may use the information returned at the database manager level to help you tune the SHEAPTHRES configuration parameter. If the element value is greater than or equal to SHEAPTHRES, it means that the sorts are not getting the full sort heap as defined by the SORTHEAP parameter. |
| Avg_sort_heap_space_used
|
The average sort heap space used by each sort |
Pages
|
If the SORTHEAP configuration parameter is substantially larger than the average sort heap used, you may be able to lower the value of this parameter.
|
| Sort_rate
|
The number of sort operations performed during the last measurement period. |
Sorts/Sec
|
|
| Pct_sort_overflow
|
The percentage of sorts that had to overflow to disk |
Percent
|
Sort overflows are sorts that ran out of sort heap and may have required disk space for temporary storage. When a sort overflows, additional overhead will be incurred because the sort will require a merge phase and can potentially require more I/O, if data needs to be written to disk. If this percentage is high, you may want adjust the database configuration by increasing the value of sortheap.
|
| Avg_sort_time
|
Indicates the average sort time for all sorts performed by all applications connected to a particular database. |
Secs
|
A high value indicates the poor performance of sorting operations. Identify the statements that spend lot of time sorting. You may want to reduce the average sort time for these statements by increasing the sortheap parameter.
|