Sorted list probe icon

Sorted List Probe

The Sorted List Probe icon indicates that the selection criteria that match the key columns used to create the temporary sorted list will be probed to find all of the matching values stored within the sorted list. A sorted list probe is generally considered when determining the implementation for a secondary table of a join when either the join condition uses an operator other than equal or a temporary hash table is not allowed in this query environment. The use of a sorted list probe will allow the optimizer to generate a plan that can take advantage of any non-join selection while creating the temporary sorted list. An additional benefit of using a sorted list probe is that the data structure of the temporary sorted list will usually cause the table data to remain resident within main memory after creation thus reducing paging on the subsequent probe operation. If the icon label is Sorted List Probe Distinct or Sorted List Probe Distinct, Preload, then, for each set of duplicate key entries that would be selected, only one of the entries will be processed.

Also referred to as: Sorted List Probe, Preload; Sorted List Probe Distinct; Sorted List Probe Distinct, Preload