Optimizing access plan for queries with a nested loop join

摘要

A method, computing system and computer program product are provided. A nested loop join access plan for a query is executed and processed records of a most outer table of a nested loop join that satisfy local predicates are counted. When a count of the processed records is not less than a threshold value, a cost to complete execution of the nested loop join access plan and a cost of executing a new access plan based on recalculated filter factors for local predicates of the query are compared. When the cost to complete is less, execution of the nested loop join access plan is resumed to complete running of the query. When the cost of executing the new access plan is less, the new access plan is executed to rerun the query. A result of the query is provided.