Systems and methods for proactive caching utilizing OLAP variants

• US 7,689,605 B2
• Filed: 01/11/2006
• Issued: 03/30/2010
• 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): Rones; Charles
• Assistant Examiner(s): Adams; Charles D
• Application Number:
  US11/329,446
• Publication Number:
  US 20060112137A1
• Time in Patent Office: 1,539 Days
• Field of Search: None
• US Class Current: 707/600
• 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 computer readable medium comprising a data structure that facilitates data analysis and building of a cache, the data structure comprising:

dynamic multidimensional analysis data, wherein the multidimensional analysis data is based, at least in part, on a proactive caching structure that builds at least one cache based on a multidimensional object derived from a database, wherein;

the multidimensional object is a relational online analytical processing (ROLAP) object that represents data of the database;

the cache is a multidimensional online analytical processing (MOLAP) cache; and

the MOLAP cache includes the same information as the ROLAP object, such that the MOLAP cache and the ROLAP object are equivalent;

an analysis component that;

utilizes the MOLAP cache to provide the dynamic multidimensional analysis data;

detects changes to the ROLAP object causing the ROLAP object to differ from the MOLAP cache; and

upon detecting changes to the ROLAP object, rebuilding the MOLAP cache, and wherein the ROLAP object provides the dynamic multidimensional analysis data while rebuilding the MOLAP cache, until the MOLAP cache is rebuilt to again be equivalent to the ROLAP object.

2. The computer readable storage medium of claim 1, wherein changes are detected in the ROLAP object when changes are made to tables in the database that affect the ROLAP object.

3. The computer readable storage medium of claim 2, wherein changes made to a database are detected from a system input comprising a database update notification.

4. The computer readable storage medium of claim 1, wherein the analysis component controls access to the MOALP cache and the ROLAP object.

5. The computer readable storage medium of claim 1, teaches wherein an old cache is removed after a rebuild.

6. The computer readable storage medium of claim 1, wherein the analysis component includes a unified dimensional model (UDM).

7. The computer readable storage medium of claim 1, wherein rebuilding the MOLAP cache is performed in a background transaction, and wherein rebuilding is also performed in response to a user instruction to rebuild the MOALP cache.

8. The computer readable storage medium of claim 1, wherein rebuilding the MOLAP cache includes:

detecting a change to the ROLAP object while rebuilding the MOLAP cache;

cancelling the rebuild of the MOLAP cache; and

restarting rebuilding of the MOLAP cache.

9. The computer readable storage medium of claim 1, wherein the MOLAP cache and the ROLAP object are stored on the same computer system.

10. The computer readable storage medium of claim 1, wherein the MOLAP cache starts unconditionally after changes to the ROLAP object are detected.

11. The computer readable storage medium of claim 1, further comprising tracking when the database was last updated.

12. A computer readable storage medium comprising computer-executable instructions that, when executed, cause a computing system to:

proactively build a Multidimensional On-Line Analytical Processing (MOLAP) object, wherein building the MOLAP object is performed by including all the information in the ROLAP object, such that the MOLAP and ROLAP objects are equivalent in information;

detect a change in the ROLAP object after building the MOLAP object;

upon detecting the change in the ROLAP object, rebuild the MOLAP object representing the ROLAP object such that the MOLAP object and the ROLAP objects are again equivalents;

cache the MOLAP object after the MOLAP object is built or rebuilt; and

analyzing data contained within the ROLAP object, wherein analyzing the data includes;

while the MOLAP object is being built or rebuilt, only analyzing the data by examining the ROLAP object directly; and

while the MOLAP object is not being built or rebuilt, only analyzing the data by examining the MOLAP object directly, such that when the MOALP and ROLAP objects are equivalent, data examination is always performed by examining the MOLAP object instead of the ROLAP object.