Huawei Technologies Co., Limited

Maozeng Li

Feng Han

Huijun Liu

Lei Qiu

Haiyan Huang

Yang Ren

A query method and a query device, where the method includes determining N execution plans respectively corresponding to N query requests according to the received N query requests, determining at least two same first sub-plans, generating a first sub-query result corresponding to any one of the at least two same first sub-plans, and in a process of generating, according to the N query requests, a query result corresponding to each of the N query requests, the same first sub-query result corresponding to any one of the first sub-plans is used for all the same first sub-plans. Hence, a large amount of repeated calculation can be reduced, database system resources are reduced, and query efficiency and a throughput of a database system in a large-scale concurrent query application scenario are improved.

Query method and query device

A method and an apparatus for determining a structured query language (SQL) execution plan are provided to optimize determining of the SQL execution plan and improve execution efficiency of the SQL execution plan. The SQL execution plan corresponds to at least one relation table. During an Niteration, the method includes obtaining a first iteration parameter generated after a first plan tree is executed on the at least one relation table during an (N&#x2212;1)iteration, where N is a natural number greater than 1, establishing a second plan tree according to the first iteration parameter, and determining the first plan tree or the second plan tree as the SQL execution plan when a difference between the second plan tree and the first plan tree is not greater than a first threshold.

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Beijing, China

Maozeng Li