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Apparatus and method for optimizing a query to a partitioned database table using a virtual maintained temporary index that spans multiple database partitionsRelated Patent Categories: Data Processing: Database And File Management Or Data Structures, Database Or File Accessing, Access Augmentation Or OptimizingApparatus and method for optimizing a query to a partitioned database table using a virtual maintained temporary index that spans multiple database partitions description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070226176, Apparatus and method for optimizing a query to a partitioned database table using a virtual maintained temporary index that spans multiple database partitions. Brief Patent Description - Full Patent Description - Patent Application Claims
BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] This invention generally relates to database systems, and more specifically relates to an apparatus and method for optimizing database queries. [0003] 2. Background Art [0004] Database systems have been developed that allow a computer to store a large amount of information in a way that allows a user to search for and retrieve specific information in the database. For example, an insurance company may have a database that includes all of its policy holders and their current account information, including payment history, premium amount, policy number, policy type, exclusions to coverage, etc. A database system allows the insurance company to retrieve the account information for a single policy holder among the thousands and perhaps millions of policy holders in its database. [0005] Retrieval of information from a database is typically done using queries. A query usually specifies conditions that apply to one or more columns of the database, and may specify relatively complex logical operations on multiple columns. The database is searched for records that satisfy the query, and those records are returned as the query result. [0006] Queries are typically optimized by generating an access plan that will speed their execution. The work required to generate an access plan is greatly increased for a query to a partitioned database table, where multiple partitions are defined that collectively make up the overall database table. Sometimes the increased work for optimizing a query to a partitioned database table negates the desired performance enhancement that drove the partitioning of the database in the first place. Without a way to improve the efficiency of queries to partitioned database tables, existing database systems will suffer from reduced performance when optimizing queries to partitioned database tables. BRIEF SUMMARY OF THE INVENTION [0007] According to the preferred embodiments, a query optimizer optimizes a query to a partitioned database table by determining common characteristics of the partitions and generating a virtual maintained temporary index that spans multiple partitions. Using the virtual maintained temporary index allows the query optimizer to generate an access plan based on the virtual maintained temporary index. This relieves the optimizer from having to individually optimize access to each partition for partitions that share common characteristics, or from optimizing the query using a common strategy for all of the partitions. [0008] The foregoing and other features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) [0009] The preferred embodiments of the present invention will hereinafter be described in conjunction with the appended drawings, where like designations denote like elements, and: [0010] FIG. 1 is a block diagram of an apparatus in accordance with the preferred embodiments; [0011] FIG. 2 is a block diagram of a sample partitioned database table as is known in the prior art; [0012] FIG. 3 is a sample query to the partitioned database table in FIG. 2; [0013] FIG. 4 is a block diagram showing how a prior art query optimizer performs a union of four separate access plans that correspond to the four partitions in the table of FIG. 2 to generate an overall access plan for the query of FIG. 3; [0014] FIG. 5 is a block diagram that shows three separate and independent maintained temporary indexes for three of the four partitions in the partitioned database table in FIG. 2; [0015] FIG. 6 is a block diagram showing the generation of a virtual maintained temporary index that spans multiple partitions in accordance with the preferred embodiments; [0016] FIG. 7 is a block diagram showing a first way for the optimizer to process the VMTI shown in FIG. 6 by expanding the VMTI to corresponding individual MTIs over the individual partitions; [0017] FIG. 8 is a block diagram showing a second way for the optimizer to process the VMTI shown in FIG. 6 by expanding the VMTI over three of the individual partitions; [0018] FIG. 9 is a flow diagram of a method for optimizing a database query to a partitioned table in accordance with the preferred embodiments; [0019] FIG. 10 is a flow diagram of a method for an access plan to register ownership of a VMTI; and [0020] FIG. 11 is a flow diagram of a method for keeping temporary indexes ineligible for deletion as long as they are owned by an access plan. DETAILED DESCRIPTION OF THE INVENTION Continue reading about Apparatus and method for optimizing a query to a partitioned database table using a virtual maintained temporary index that spans multiple database partitions... Full patent description for Apparatus and method for optimizing a query to a partitioned database table using a virtual maintained temporary index that spans multiple database partitions Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Apparatus and method for optimizing a query to a partitioned database table using a virtual maintained temporary index that spans multiple database partitions patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Apparatus and method for optimizing a query to a partitioned database table using a virtual maintained temporary index that spans multiple database partitions or other areas of interest. ### Previous Patent Application: Smart share technologies for automatically processing digital information Next Patent Application: Evaluating a current partitioning of a database Industry Class: Data processing: database and file management or data structures ### FreshPatents.com Support Thank you for viewing the Apparatus and method for optimizing a query to a partitioned database table using a virtual maintained temporary index that spans multiple database partitions patent info. IP-related news and info Results in 0.51056 seconds Other interesting Feshpatents.com categories: Electronics: Semiconductor , Audio , Illumination , Connectors , Crypto , 174 |
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