Inquiry planning method and device

Abstract

An embodiment of the invention provides an inquiry planning method and device. The inquiry planning method includes receiving an inquiry request message; determining at least one inquiry path according to operation objects of the inquiry request message, wherein each inquiry path includes at least one inquiry operating step; determining execution costs of each inquiry path according to each inquiry path; determining the inquiry path with minimum execution cost to be the optimal inquiry path; selecting memories for executing the inquiry operating steps according to operational capability of the current memories and set rules; and assigning the optimal inquiry path to an executer, and scheduling the inquiry operating steps of the optimal inquiry path to each memory to perform execution. By means of the inquiry planning method and device, the memories determined during optimal inquiry path planning can be used for executing steps of the optimal inquiry path so as to acquire inquiry results, and actual minimum execution costs of the inquiry results acquired by the optimal inquiry path can be guaranteed.

Description

technical field [0001] Embodiments of the present invention relate to computer database technology, and in particular to a query planning method and device. Background technique [0002] When the client sends a query request to the master server of the database to query the data in the database, the master server determines the "best execution plan" for the query request through the "query planner". When planning”, usually according to the calculation cost, disk reading speed and other factors, the execution steps that can realize the query request and the ordering relationship between each operation step are determined first, and at least one “execution plan” is generated, and each “execution plan” constitutes the search space , the master server then estimates the cost of the "execution plan" in the search space, and determines the "execution plan" with the least cost as the "best execution plan" for the query request according to the cost estimation results. The query exe...

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