Snapshot Information Level Database Manager |
API Structure(s) sqlm_db2 |
Monitor Group Basic |
Resettable |
Yes |
|
API Element Name Element Type |
piped_sorts_requested counter |
Description: The number of piped sorts that have been requested.
Usage: Each active sort on the system allocates memory, which may result in sorting taking up too much of the available system memory.
The sort list heap (sortheap) and sort heap threshold (sheapthres) configuration parameters help to control the amount of memory used for sort operations. These parameters are also used to determine whether a sort will be piped.
Since piped sorts may reduce disk I/O, allowing more piped sorts can improve the performance of sort operations and possibly the performance of the overall system. A piped sort is not be accepted if the sort heap threshold will be exceeded when the sot heap is allocated for the sort. See "Piped Sorts Accepted" for more information if you are experiencing piped sort rejections.
The SQL EXPLAIN output will show whether the optimizer requests a piped sort. For more information on piped and non-piped sorts see the Administration Guide.
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