Title:
SELECTION RATE ESTIMATION METHOD AND APPARATUS
Document Type and Number:
WIPO Patent Application WO/2024/041221
Kind Code:
A1
Abstract:
A selection rate estimation method, comprising: acquiring a query statement, which is input by a user, wherein the query statement comprises an equivalence condition; determining whether a selected value of the equivalence condition is a null value, or whether the selected value of the equivalence condition falls within the most frequent value array; and when the selected value of the equivalence condition is not a null value and does not fall within the most frequent value array, determining a selection rate of the equivalence condition according to statistical information of a histogram in a database. When a selection rate is estimated, on the basis of statistical information of a histogram which is pre-generated in a database, the distribution condition of data is taken into consideration, so as to obtain a selection rate of an equivalence condition in a query statement, which is input by a user. That is, by means of lightweight calculation, an optimizer generates a better execution plan, thereby reducing the calculation amount of the optimizer while the performance of the optimizer is ensured.
Inventors:
ZHOU ZHAOQI (CN)
ZHANG SHUJIE (CN)
LIU BAOZHU (CN)
ZHANG SHUJIE (CN)
LIU BAOZHU (CN)
Application Number:
PCT/CN2023/105172
Publication Date:
February 29, 2024
Filing Date:
June 30, 2023
Export Citation:
Assignee:
HUAWEI TECH CO LTD (CN)
International Classes:
G06F16/2453
Foreign References:
| US4956774A | 1990-09-11 | |||
| CN101105802A | 2008-01-16 | |||
| CN111274270A | 2020-06-12 | |||
| EP1548612A1 | 2005-06-29 |
Attorney, Agent or Firm:
E-TONE INTELLECTUAL PROPERTY FIRM (GENERAL PARTNERSHIP) (CN)
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