Distributed database multi-join query optimization algorithm

A query optimization and database technology, applied in the database field, can solve the problem of high cost of query algorithms, and achieve the effects of reducing scale, reducing search space, and improving efficiency

Inactive Publication Date: 2010-06-16
山东省标准化研究院
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Problems solved by technology

[0011] For the query of massive information and complex query, the cost of the curr

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  • Distributed database multi-join query optimization algorithm

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Embodiment Construction

[0027] The specific implementation of the present invention is further described below:

[0028] Step 1: Divide the relational connections in the query into two categories: binary relational connections, and connections of more than ternary relations;

[0029] Step 2: Load the statistical information in the database, including the statistical information of each site segment, resource information and communication information, etc., and estimate the connection cost of the relationship as the weight of the edge;

[0030] Step 3: Pre-optimize the operation sequence of the ternary or more connections. Determine the optimal order of operations for each of the three or more connections, which is the same as the query operation in the centralized database, which can use existing effective strategies and methods, and can be processed in parallel;

[0031] Step 4: Preprocessing rules: If there is only a connection operation between a ternary connection and another relationship, the t...

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Abstract

The invention provides a query optimization algorithm in the technical field of database, and is mainly used for solving the problem of distributed database multi-join query optimization. The technical scheme adopted by the invention is as follows: 1. pre-optimizing over-ternary relation join, and reducing searching space optimized by the operation sequence of the relation join; 2. formulating a pretreatment rule, and merging all relation joins after pre-optimization; 3. loading database statistic information, evaluating load of each processor, taking balanced load and minimum transmission cost between processors as a target, and adopting a graph partitioning method to distribute the relation joins to multiple processors for optimization. The invention can reduce the searching space optimized by the operation sequence of the joins by pre-optimizing multi-join, uses a collateral mechanism to reduce the scale of the optimization subproblem, and improves the efficiency of the multi-join query optimization effectively.

Description

technical field [0001] The invention relates to the technical field of databases, in particular to a three-stage multi-connection query optimization method for a distributed database. The algorithm is used to optimize multi-connection operations in the query process to improve query efficiency. Background technique [0002] Data and information are becoming more and more important in today's social activities, and have become an extremely important resource for human development. Distributed database is the product of mutual coordination and infiltration of computer network and database technology. It improves the reliability and availability of the system by increasing data redundancy, but at the same time makes distributed query processing more complicated. Therefore, the query of distributed database Optimization is very important in distributed database technology. [0003] Distributed query processing has the ability to access data at remote sites through a communicati...

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Application Information

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IPC IPC(8): G06F17/30
Inventor 高永超钱恒刘丽梅王云争王玎
Owner 山东省标准化研究院
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