scholarly journals ESTIMATION OF ATTRIBUTE VALUES IN JOIN TABLES WHILE OPTIMIZING RELATION-AL DATABASE QUERY

2021 ◽  
pp. 3-18
Author(s):  
Y.A. Grigorev ◽  
◽  
O.Yu. Pluzhnikova ◽  
Keyword(s):  
Relational Database ◽  
Database Query ◽  
Query Plan ◽  
Cardinality Estimation ◽  
The Cost

The article analyzes the problem of estimating join tables cardinality in the process of calculating the cost of relational database query plan. A new algorithm for estimating the distinct values of attributes is proposed. The algorithm allows reducing inaccuracy in cardinality estimation. The consistency of proposed algorithm is proved.

Estimating the cost of updates in a relational database

1985 ◽  
Vol 10 (2) ◽  
pp. 163-179 ◽  
Author(s):  
M. Schkolnick ◽  
P. Tiberio
Keyword(s):  
Relational Database ◽  
The Cost

The Research of Workflow Engine States

2013 ◽  
Vol 347-350 ◽  
pp. 2236-2240
Author(s):  
Yan Rong Shi ◽  
Tao Hou
Keyword(s):  
Information System ◽  
Full Advantage ◽  
Relational Database ◽  
Database Systems ◽  
Database System ◽  
Workflow Engine ◽  
Relational Database System ◽  
Logical Design ◽  
Relational Database Systems ◽  
The Cost

Based on the analysis of the workflow patterns, this paper designs the active state of the workflow, and puts forward the idea of the logical design of the engine driven. It can conveniently define the information model of the workflow based on relational database systems, it can effectively reduce the difficulty on the technical development of the workflow engine and take full advantage of existing relational database system to realize the information system that has the nature of the workflow and reduce the cost of the implementation.

Model for Determining Paratransit Eligibility under the Americans with Disabilities Act

2005 ◽  
Vol 1903 (1) ◽  
pp. 78-85
Author(s):  
Carol R. Denson
Keyword(s):  
Cost Effectiveness ◽  
Relational Database ◽  
Infinite Number ◽  
Americans With Disabilities Act ◽  
Computational Algorithm ◽  
Large Array ◽  
Environmental Characteristics ◽  
The Cost

A model is described for the rational characterization and determination of paratransit eligibility for individuals under the Americans with Disabilities Act. The model refines the process of determining paratransit eligibility by comparing, at the microstructure level, the mobility characteristics of a given individual with the environmental characteristics for a given trip. The large array of data that results presents an infinite number of possibilities in the comparison. A relational database was therefore created, along with a specially designed computational algorithm, to generate these comparisons quickly. Thus, the model provides the capability to make eligibility determinations quickly and objectively. In addition, the model allows for the virtual removal of selected barriers and then prediction of the cost-effectiveness that results from the reduced need for selected paratransit trips.

Towards a Flexible Relational Database Query System

2021 ◽  
Author(s):  
Rachid Mama ◽  
Mustapha Machkour ◽  
Karam Ahkouk ◽  
Khadija Majhadi
Keyword(s):  
Relational Database ◽  
Database Query ◽  
Query System

Data Abstraction Technique for Relational Database Query Processing

1986 ◽  
Vol 17 (2) ◽  
pp. 12-20
Author(s):  
Takumi Ohtani ◽  
Takanobu Baba ◽  
Masayuki Inagawa ◽  
Takao Iwasaki ◽  
Kenzo Okuda ◽  
...  
Keyword(s):  
Query Processing ◽  
Relational Database ◽  
Data Abstraction ◽  
Database Query ◽  
Database Query Processing

scholarly journals A Survey on Advancing the DBMS Query Optimizer: Cardinality Estimation, Cost Model, and Plan Enumeration

2021 ◽  
Vol 6 (1) ◽  
pp. 86-101
Author(s):  
Hai Lan ◽  
Zhifeng Bao ◽  
Yuwei Peng
Keyword(s):  
Cost Model ◽  
Database Systems ◽  
Enumeration Algorithm ◽  
Estimation Errors ◽  
Cardinality Estimation ◽  
Execution Plan ◽  
Query Optimizer ◽  
Almost All ◽  
The Cost

AbstractQuery optimizer is at the heart of the database systems. Cost-based optimizer studied in this paper is adopted in almost all current database systems. A cost-based optimizer introduces a plan enumeration algorithm to find a (sub)plan, and then uses a cost model to obtain the cost of that plan, and selects the plan with the lowest cost. In the cost model, cardinality, the number of tuples through an operator, plays a crucial role. Due to the inaccuracy in cardinality estimation, errors in cost model, and the huge plan space, the optimizer cannot find the optimal execution plan for a complex query in a reasonable time. In this paper, we first deeply study the causes behind the limitations above. Next, we review the techniques used to improve the quality of the three key components in the cost-based optimizer, cardinality estimation, cost model, and plan enumeration. We also provide our insights on the future directions for each of the above aspects.

scholarly journals Cost-Based Query Optimization in Centralized Relational Databases

2019 ◽  
Vol 24 (1) ◽  
pp. 42-46
Author(s):  
Nawaraj Paudel ◽  
Jagdish Bhatta
Keyword(s):  
Query Optimization ◽  
Relational Databases ◽  
Query Language ◽  
Database Management System ◽  
Query Plan ◽  
Efficiency Cost ◽  
The Cost ◽  
Disk Access ◽  
The Given ◽  
Relational Database Management

Query optimization is the most significant factor for any centralized relational database management system (RDBMS) that reduces the total execution time of a query. Query optimization is the process of executing a SQL (Structured Query Language) query in relational databases to determine the most efficient way to execute a given query by considering the possible query plans. The goal of query optimization is to optimize the given query for the sake of efficiency. Cost-based query optimization compares different strategies based on relative costs (amount of time that the query needs to run) and selects and executes one that minimizes the cost. The cost of a strategy is just an estimate based on how many estimated CPU and I/O resources that the query will use. In this paper, cost is considered by counting number of disk accesses for each query plan because disk access tends to be the dominant cost in query processing for centralized relational databases.

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