Abstract: A query is received. The query comprises a plural number of efficiency expressions. A key is generated for the query indicating a first selectivity region in multi-dimensional selectivity space comprising an array of selectivity regions arranged according to a grid with a number of dimensions equal to the plural number. The generated key is used to look up a stored query plan among a plurality of stored query plans. A stored query plan is executed for the query that is associated with a stored key determined to match the generated key.

Abstract: A query is received. The query comprises a plural number of efficiency expressions. A key is generated for the query indicating a first selectivity region in multi-dimensional selectivity space comprising an array of selectivity regions arranged according to a grid with a number of dimensions equal to the plural number. The generated key is used to look up a stored query plan among a plurality of stored query plans. A stored query plan is executed for the query that is associated with a stored key determined to match the generated key.

Abstract: A query configured according to a query template is received. The query includes values for a plurality of parameters. A key is generated for the query that indicates a selectivity region in a selectivity space determined for the included parameter values. Whether the generated key matches any key of a plurality of keys is determined. Each key of the plurality of keys is associated with a corresponding query plan. If the generated key is determined to not match any of the keys, the query is compiled to generate a new query plan, and the generated query plan is executed with respect to the query. If the key is determined to match any key of the plurality of keys, a query plan associated with the matched key is selected, and the query plan associated with the matched key is executed with respect to the query.

Abstract: A query configured according to a query template is received. The query includes values for a plurality of parameters. A key is generated for the query that indicates a selectivity region in a selectivity space determined for the included parameter values. Whether the generated key matches any key of a plurality of keys is determined. Each key of the plurality of keys is associated with a corresponding query plan. If the generated key is determined to not match any of the keys, the query is compiled to generate a new query plan, and the generated query plan is executed with respect to the query. If the key is determined to match any key of the plurality of keys, a query plan associated with the matched key is selected, and the query plan associated with the matched key is executed with respect to the query.