Processing of data chunks using a database calculation engine

• US 10,255,316 B2
• Filed: 11/18/2015
• Issued: 04/09/2019
• Est. Priority Date: 11/18/2015
• Status: Active Grant

• Current Assignee: SAP SE
• Original Assignee: SAP SE
• Inventors: Weyerhaeuser, Christoph, Bakulina, Alena, Mindnich, Tobias, Merx, Johannes, Schwing, Julian
• Primary Examiner(s): Bibbee, Jared M
• Application Number:
  US14/945,339
• Publication Number:
  US 20170139982A1
• Time in Patent Office: 1,238 Days
• CPC Class Codes: G06F 16/2425 Iterative querying; Query formulation based on the results of a preceding query
• CPC Class Codes: G06F 16/25 Integrating or interfacing systems involving database management systems

Abstract

A database server receives a request to perform a primary query on a table of a database. A first table query can be generated and can include a starting row identifier, ROW A, and a number of rows, n, for generating a data chunk from the table of the database. Multiple table queries can be performed each having a different starting row identifier and each defining the number of rows forming a data chunk. The primary query can be extended with the first table query in preparation for performing the primary query on the first data chunk.

Claims

1. A method to be performed on one or more data processors comprising at least part of a computer system, the method comprising:

receiving, at the one or more data processors, a request to perform a primary query on a table stored in a database;

determining, in response to the request, that the table exceeds a size limit of a main memory of a database management system associated with the database; and

in response to the determination that the table exceeds the size limit of the main memory of the database management system,

generating, by the one or more data processors, a first table query and a second table query, the first table query defining, based at least on a first starting row identifier and a first number of rows, a first data chunk from the table of the database, and the second table query defining, based at least on a second starting row identifier and a second number of rows, a second data chunk from the table of the database,

executing the first table query to at least load, into the main memory, the first data chunk,

performing the primary query on the first data chunk in the main memory, the primary query being performed on the first data chunk prior to executing the second table query to at least load, into the main memory, the second data chunk and performing the primary query on the second data chunk in the main memory, the loading of the second data chunk into the main memory overwriting the first data chunk in the main memory, and

in response to the table including additional data in excess of the first data chunk and the second data chunk, generating and executing a third table query to at least load, into the main memory, a third data chunk including the additional data, and executing the primary query on the third data chunk in the main memory.

2. The method of claim 1, further comprising:

presenting, to one or more clients of the database management system, a result of the primary query being performed on the first data chunk and/or the second data chunk.

3. The method of claim 1, wherein the response to the determination that the table exceeds the size limit of the main memory of the database management system further comprises:

upon executing the primary query on the first data chunk in the main memory, executing the second table query to at least load, into the main memory, the second data chunk; and

performing the primary query the second data chunk in the main memory.

4. The method of claim 3, wherein the table comprises a plurality of rows, and wherein each of the plurality of rows is associated with a unique row identifier.

5. The method of claim 3, wherein the first starting row, the first number of rows, the second starting row, and the second number of rows are selected to ensure that the first data chunk and the second data chunk include different rows from the table.

6. The method of claim 1, further comprising:

preventing, by the one or more data processors, data in the table of the database from being modified during the execution of the first table query to load the first data chunk into the main memory.

7. The method of claim 3, wherein the primary query defines a calculation scenario that comprises one or more calculation nodes, wherein the one or more calculation scenario specifies a plurality of attributes, and wherein the primary query require a subset of the plurality of attributes comprising the first data chunk and/or the second data chunk.

8. The method of claim 7, further comprising:

determining, by the one or more data processors, a size of the first data chunk and/or the second data chunk.

9. The method of claim 8, wherein the size of the first data chunk and/or the second data chunk is determined based on the subset of the plurality of attributes.

10. The method of claim 9, wherein determining the size of the first data chunk and/or the second data chunk is further determined based on the size limit of the main memory of the database management system.

21. The method of claim 1, further comprising:

determining, in response to the request, that the table includes data not required by the primary query; and

in response to the determination that the table includes data not required by the primary query, preventing a fourth data chunk from being loaded into the main memory of the database management system, the fourth data chunk including the data not required by the primary query.

11. A system comprising:

at least one data processor; and

,

a memory coupled to the at least one data processor, the memory storing instructions, which, when executed, cause the at least one data processor to perform operations comprising;

receiving, at the one or more data processors, a request to perform a primary query on a table stored in a database;

determining, in response to the request, that the table exceeds a size limit of a main memory of a database management system associated with the database; and

in response to the determination that the table exceeds the size limit of the main memory of the database management system,

generating, by the one or more data processors, a first table query and a second table query, the first table query defining, based at least on a first starting row identifier and a first number of rows, a first data chunk from the table of the database, and the second table query defining, based at least on a second starting row identifier and a second number of rows, a second data chunk from the table of the database,

executing the first table query to at least load, into the main memory, the first data chunk,

performing the primary query on the first data chunk in the main memory, the primary query being performed on the first data chunk prior to executing the second table query to at least load, into the main memory, the second data chunk and performing the primary query on the second data chunk in the main memory, the loading of the second data chunk into the main memory overwriting the first data chunk in the main memory, and

in response to the table including additional data in excess of the first data chunk and the second data chunk, generating and executing a third table query to at least load, into the main memory, a third data chunk including the additional data, and executing the primary query on the third data chunk in the main memory.

12. The system of claim 11, wherein the operations further comprise:

presenting, to one or more clients of the database management system, a result of the primary query being performed on the first data chunk and/or the second data chunk.

13. The system of claim 11, wherein the response to the determination that the table exceeds the size limit of the main memory of the database management system further comprises:

upon executing the primary query on the first data chunk in the main memory, executing the second table query to at least load, into the main memory, the second data chunk; and

performing the primary query the second data chunk in the main memory.

14. The system of claim 13, wherein the table comprises a plurality of rows, and wherein each of the plurality of rows is associated with a unique row identifier.

15. The system of claim 13, wherein the first starting row, the first number of rows, the second starting row, and the second number of rows are selected to ensure that the first data chunk and the second data chunk include different rows from the table.

16. The system of claim 11, wherein the operations further comprise:

preventing, by the one or more data processors, data in the table of the database from being modified during the execution of the first table query to load the first data chunk into the main memory.

17. The system of claim 13, wherein the primary query defines a calculation scenario that comprises one or more calculation nodes, wherein the one or more calculation scenario specifies a plurality of attributes, and wherein the primary query require a subset of the plurality of attributes comprising the first data chunk and/or the second data chunk.

18. The system of claim 17, wherein the operations further comprise:

determining, by the one or more data processors, a size of the first data chunk and/or the second data chunk.

19. The system of claim 18, wherein the size of the first data chunk and/or the second data chunk is determined based on the subset of the plurality of attributes.

20. The system of claim 19, wherein determining the size of the first data chunk and/or the second data chunk is further determined based on the size limit of the main memory of the database management system.

22. A non-transitory computer-readable medium storing instructions, which when executed by at least one data processor, result in operations comprising:

receiving, at the one or more data processors, a request to perform a primary query on a table stored in a database;

determining, in response to the request, that the table exceeds a size limit of a main memory of a database management system associated with the database; and

in response to the determination that the table exceeds the size limit of the main memory of the database management system,

generating, by the one or more data processors, a first table query and a second table query, the first table query defining, based at least on a first starting row identifier and a first number of rows, a first data chunk from the table of the database, and the second table query defining, based at least on a second starting row identifier and a second number of rows, a second data chunk from the table of the database,

executing the first table query to at least load, into the main memory, the first data chunk,

performing the primary query on the first data chunk in the main memory, the primary query being performed on the first data chunk prior to executing the second table query to at least load, into the main memory, the second data chunk and performing the primary query on the second data chunk in the main memory, the loading of the second data chunk into the main memory overwriting the first data chunk in the main memory, and

in response to the table including additional data in excess of the first data chunk and the second data chunk, generating and executing a third table query to at least load, into the main memory, a third data chunk including the additional data, and executing the primary query on the third data chunk in the main memory.