Systems and methods for proactive caching utilizing OLAP variants

• US 7,680,776 B2
• Filed: 01/11/2006
• Issued: 03/16/2010
• Est. Priority Date: 03/28/2003
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Petculescu, Cristian, Conlon, Thomas P., Netz, Amir
• Primary Examiner(s): Rone; Charles
• Assistant Examiner(s): Adams; Charles D
• Application Number:
  US11/329,616
• Publication Number:
  US 20060129597A1
• Time in Patent Office: 1,525 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G06F 16/283 Multi-dimensional databases or data warehouses, e.g. MOLAP or ROLAP
• CPC Class Codes: Y10S 707/954 Relational
• CPC Class Codes: Y10S 707/957 Multidimensional
• CPC Class Codes: Y10S 707/99931 Database or file accessing
• CPC Class Codes: Y10S 707/99933 Query processing, i.e. searching

Abstract

The present invention leverages MOLAP performance for ROLAP objects (dimensions, partitions and aggregations) by building, in a background process, a MOLAP equivalent of that object. When the background processing completes, queries are switched from ROLAP queries to MOLAP queries. When changes occur to relevant relational objects (such as tables that define content of OLAP objects), an OLAP object is switched back to a ROLAP mode, and all relevant caches are dropped while, as a background process, a new MOLAP equivalent is created.

Claims

1. A method for proactively caching data of a database utilizing online analytical processing (OLAP) variants, the method being performed by a processor of a computer system having a database, the method comprising:

creating a relational OLAP (ROLAP) object that represents data of the database;

building a multidimensional OLAP (MOLAP) cache equivalent of the ROLAP object such that the MOLAP cache stores the same data of the database that is represented by the ROLAP object, the MOLAP cache and ROLAP object being stored on the computer system;

receiving a first query, at the computer system, for a portion of the data;

accessing the MOLAP cache to resolve the first query;

receiving an indication, at the computer system, that the data of the database represented by the ROLAP object has been updated;

rebuilding the MOLAP cache such that the MOLAP cache contains the updated data;

receiving a second query, at the computer system, for a portion of the data while the MOLAP cache is being rebuilt;

accessing the ROLAP object to resolve the second query while the MOLAP cache is being rebuilt;

receiving a third query, at the computer system, for a portion of the data after the MOLAP cache is rebuilt; and

accessing the MOLAP cache to resolve the third query.

2. The method of claim 1, wherein the MOLAP cache is built and rebuilt using a background process.

3. The method of claim 1, further comprising:

receiving an indication while the MOLAP cache is being rebuilt that the data of the database has been updated; and

restarting the rebuild of the MOLAP cache to account for the update to the data.

4. The method of claim 1, wherein rebuilding of the MOLAP cache is started after a specified amount of time after the update to the data occurs.

5. The method of claim 1, further comprising:

receiving user input that specifies that the MOLAP cache should be rebuilt; and

rebuilding the MOLAP cache in response to the user input.

6. The method of claim 1, further comprising:

rebuilding the MOLAP cache after a specified amount of time even when the data of the database has not been updated.

7. A computer storage medium storing computer executable instructions which when executed by a processor of a computer system proactively cache data of a database utilizing online analytical processing (OLAP) variants, the computer executable instructions performing the following:

creating a relational OLAP (ROLAP) object that represents data of the database;

building a multidimensional OLAP (MOLAP) cache equivalent of the ROLAP object such that the MOLAP cache stores the same data of the database that is represented by the ROLAP object, the MOLAP cache and ROLAP object being stored on the computer system;

receiving a first query, at the computer system, for a portion of the data;

accessing the MOLAP cache to resolve the first query;

receiving an indication, at the computer system, that the data of the database represented by the ROLAP object has been updated;

rebuilding the MOLAP cache such that the MOLAP cache contains the updated data;

receiving a second query, at the computer system, for a portion of the data while the MOLAP cache is being rebuilt;

accessing the ROLAP object to resolve the second query while the MOLAP cache is being rebuilt;

receiving a third query, at the computer system, for a portion of the data after the MOLAP cache is rebuilt; and

accessing the MOLAP cache to resolve the third query.

8. The computer storage medium of claim 7, wherein the MOLAP cache is built and rebuilt using a background process.

9. The computer storage medium of claim 7, wherein the computer executable instructions further perform:

receiving an indication while the MOLAP cache is being rebuilt that the data of the database has been updated; and

restarting the rebuild of the MOLAP cache to account for the update to the data.

10. The computer storage medium of claim 7, wherein rebuilding of the MOLAP cache is started after a specified amount of time after the update to the data occurs.

11. The computer storage medium of claim 7, wherein the computer executable instructions further perform:

receiving user input that specifies that the MOLAP cache should be rebuilt; and

rebuilding the MOLAP cache in response to the user input.

12. The computer storage medium of claim 7, wherein the computer executable instructions further perform:

rebuilding the MOLAP cache after a specified amount of time even when the data of the database has not been updated.