SAP SE
Robustness metrics for optimization of query execution plans

Abstract:

A method may include responding to a query to retrieve data from a database by identifying a plurality of query execution plans. An overall robustness value may be determined for each query execution plan. The overall robustness value of a query execution plan may correspond to a sum of individual robustness values for each operator included in the query execution plan. Each operator may have an individual robustness value that corresponds to a first change in a total cost of a query execution plan including the operator relative to a second change in an output cardinality of the operator. One of the plurality of query execution plans may be selected based on the overall robustness value of each of the plurality of query execution plans. The query may be executed by performing a sequence of operators included in the selected one of the plurality of query execution plan.