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Query plan optimization method and system in distributed database

A query plan and database technology, applied in the field of SQL query optimization, can solve problems affecting the execution efficiency of SQL statements, etc., and achieve the effects of enhancing data screening capabilities, reducing data volume, and enhancing data screening capabilities

Pending Publication Date: 2021-07-23
联通沃音乐文化有限公司 +1
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  • Claims
  • Application Information

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Problems solved by technology

In database query, the amount of data transferred across the network will largely affect the execution efficiency of SQL statements

Method used

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  • Query plan optimization method and system in distributed database
  • Query plan optimization method and system in distributed database
  • Query plan optimization method and system in distributed database

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Embodiment Construction

[0033] The present disclosure will now be discussed with reference to various exemplary embodiments. It should be understood that the discussion of these embodiments is only for the purpose of enabling those skilled in the art to better understand and thus implement the embodiments of the present disclosure, rather than teaching any limitation to the scope of the present disclosure.

[0034] In database query, when connecting two or more tables in the query plan, it is necessary to filter the data of the driving table or the front table as much as possible in advance, even if the relevant filter conditions of the front table need to rely on the back table; However, in traditional algorithms, it is currently difficult to realize the technology of filtering the data of the pre-table relying on the query conditions of the post-table. Aiming at the problems existing in the traditional centralized query plan optimization algorithm with strong statistical information in the distribu...

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Abstract

The invention relates to a query plan optimization method and system in a distributed database. The method comprises the following steps: selecting a reference table based on the number of constant correlation conditions of each table in a query plan; based on one or more current constant correlation conditions in the reference table, evaluating constant correlation conditions of one or more columns without the constant correlation conditions in the reference table; generating a constant correlation condition combination for the reference table based on the current constant correlation condition and the evaluated constant correlation condition; and passing the constant correlation condition combination to one or more other tables associated with the reference table in the query plan to extend the query condition of each table.

Description

technical field [0001] The present application relates to SQL query optimization, in particular to a query plan optimization method and system in a distributed database. Background technique [0002] In actual database applications, it is often necessary to read or query data from multiple data tables, which can usually be achieved by using a join (JOIN) in a Structured Query Language (Structured Query Language, SQL) statement. [0003] The query plan of the database for data table connection usually first determines a driving table, then filters the data of the driving table based on the SQL statement conditions, and then passes the connection method based on the filtered data for the driving table (for example, nested loop connection (nest-loop) or hash join (hash join)) to perform data association with subsequent tables to complete efficient joins. [0004] However, the above method has some disadvantages in the distributed database architecture where computing nodes and...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F16/2453G06F16/2458G06F16/27
CPCG06F16/2453G06F16/2471G06F16/27
Inventor 李韩邹西山林金怡吴伟华文其瑞高孝鑫龙禹
Owner 联通沃音乐文化有限公司