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US 9,542,445 B2Granted
Using object awareness for a join pruning mechanism
AssigneeHasso-Plattner-Institut Fur Softwaresystemtechnik GmbH
InventorsHasso Plattner, Stephan Mueller, Jens Krueger, Juergen Mueller, Anisoara Nica
Life of this patent
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Abstract
The invention relates to a computer system and a corresponding method and a corresponding computer-readable medium. The computer system is suitable for determining the result of a join. Based on the access pattern of an application, the computer system infers that a particular subjoin is empty. The computer system then excludes the inferred-empty subjoin when performing the join, performing a more efficient and faster database join operation.
Claims18
A computer system for determining a result of a join, the computer system comprising:
- a processing unit;
- a database coupled to the processing unit,
- the database comprising:
- a first table, and
- a second table,
- each of the first table and the second table being partitioned into at least two partitions, including a first partition of the first table, a second partition of the first table, a first partition of the second table, and a second partition of the second table,
- the database being coupled to an application that, in operation, accesses the database according to an access pattern;
- and
- a database engine executable by the processor and communicatively coupled to the database, the database engine being configured for determining a join between the first table and the second table by:
- inferring from the access pattern of the application that at least one of a plurality of subjoins is empty, wherein the plurality of subjoins includes a first subjoin between the first partition of the first table and the first partition of the second table, a second subjoin between the first partition of the first table and the second partition of the second table, a third subjoin between the second partition of the first table and the first partition of the second table, and a fourth subjoin between the second partition of the first table and the second partition of the second table;
- determining a plurality of results for the plurality of subjoins excluding the at least one of the plurality of subjoins that was inferred to be empty;
- and
- combining the plurality of results that exclude the at least one of the plurality of subjoins that was inferred to be empty.
10 more elements
A method for determining a result of a join, the method comprising the following steps:
- providing
- a processing unit;
- a database coupled to the processing unit,
- the database comprising:
- a first table, and
- a second table,
- each of the first table and the second table being partitioned into at least two partitions, including a first partition of the first table, a second partition of the first table, a first partition of the second table, and a second partition of the second table,
- the database being coupled to an application that, in operation, accesses the database according to an access pattern,
- a database engine executable by the processor and communicatively coupled to the database,
- the database engine determining a join between the first table and the second table by:
- inferring from the access pattern of the application that at least one of a plurality of subjoins is empty, wherein the plurality of subjoins includes a first subjoin between the first partition of the first table and the first partition of the second table, a second subjoin between the first partition of the first table and the second partition of the second table, a third subjoin between the second partition of the first table and the first partition of the second table, and a fourth subjoin between the second partition of the first table and the second partition of the second table;
- determining a plurality of results for the plurality of subjoins excluding the at least one of the plurality of subjoins that was inferred to be empty;
- and
- combining the plurality of results that exclude the at least one of the plurality of subjoins that was inferred to be empty.
11 more elements
A non-transitory machine-readable medium storing a computer program that when executed by a computer system implements a method for determining a result of a join, wherein the computer system includes a processor and a memory, the method comprising:
- providing
- a processing unit;
- a database coupled to the processing unit,
- the database comprising:
- a first table, and
- a second table,
- each of the first table and the second table being partitioned into at least two partitions, including a first partition of the first table, a second partition of the first table, a first partition of the second table, and a second partition of the second table,
- the database being coupled to an application that, in operation, accesses the database according to an access pattern,
- a database engine executable by the processor and communicatively coupled to the database,
- the database engine determining a join between the first table and the second table by:
- inferring from the access pattern of the application that at least one of a plurality of subjoins is empty, wherein the plurality of subjoins includes a first subjoin between the first partition of the first table and the first partition of the second table, a second subjoin between the first partition of the first table and the second partition of the second table, a third subjoin between the second partition of the first table and the first partition of the second table, and a fourth subjoin between the second partition of the first table and the second partition of the second table;
- determining a plurality of results for the plurality of subjoins excluding the at least one of the plurality of subjoins that was inferred to be empty;
- and
- combining the plurality of results that exclude the at least one of the plurality of subjoins that was inferred to be empty.
11 more elements
Dependencies are inferred from the claim text.