Patent ID: 8938644
Filing Date: 2015-01-20
Classification: G06F

Abstract:
1. A computer-implemented method for error recovery during execution of database queries in a computer system, comprising: generating, in the computer system, a query execution plan for a request, wherein the query execution plan accesses data from a database stored on the computer system; executing, in the computer system, the query execution plan to access the data in the database; detecting occurrence of an error, a problem or a failure in the execution of the query execution plan: in response to the detection of the error, problem, or failure, identifying a plurality of workarounds to avoid the detected occurrence of the error, problem, or failure, wherein each workaround includes deactivating or activating components, features or code paths of the query execution plan, and wherein each workaround has an associated predetermined ranking with respect to one another; determining a maximum number of retry attempts based on a current workload of the computer system and at least one classification rule associated with the query execution plan; revising the query execution plan according to a workaround having a highest predetermined ranking; submitting the revised query execution plan for execution in the computer system; and repeating the revising and submitting of the query execution plan for each detected occurrence of the error, problem or occurrence associated with execution of a revision of the revised query execution plan until execution of the revised query execution plan is completed or until the maximum number of retry attempts is reached, wherein each revision of the revised query execution plan is based on a different workaround in an order of highest to lowest predetermined ranking.