Patterned based query optimization

A computer-implemented method of optimizing execution of a query, comprising:

• receiving the query;
• determining if the query fits within an established group of queries;
• and
• in response to determining the query fits within an established group of queries,
• selecting, from a group of ore-existing access plans used for prior executions of queries within the established group, an access plan for use in executing the query, and
• executing the query according to the selected access plan.

A tangible computer readable medium containing a program which, when executed, performs operations for optimizing execution of a query comprising:

• receiving the query;
• selecting, from a set of one or more pre-existing access plans used for prior executions of one of the query and a similar query, an access plan for use in executing the query;
• and
• executing the query according to the selected access plan.

A database system, comprising:

• a processor, a memory and a storage device;
• a query optimizer residing in the memory and executable by the processor;
• one or more records on the storage device, each containing a set of pre-existing access plans used in prior executions of one of the query and a similar query;
• and
• a query execution component configured to receive a query and execute the query against a database according to a pre-existing access plan selected from one of the records or an access plan generated by the query optimizer, wherein the query execution component executes the access plan generated by the optimizer only after determining that the pre-existing access plans contained in the one or more of the records fail to satisfy predetermined criteria.