#query optimizer

Design And Implementation Of A Query Optimizer

DESIGN AND IMPLEMENTATION OF A QUERY OPTIMIZER

Format: Ms Word Document

Pages:   92

Price: N5,000

Chapters: 1-5

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TABLE OF CONTENT

Title page

Approval page

Certification

Dedication

Acknowledgement

Table of content

Abstract

  Chapter One:

INTRODUCTION

1.1 Background of the study

1.2 Statement of Problem

1.3 Purpose of the study

1.4 Significance of the study

1.5 Scope of the…

How SQL Server Works

One of the tasks assigned to a Database Administrator is troubleshooting database performance issues. To be able to effectively troubleshoot performance problems you need to have a basic understanding of how SQL Server works. The somewhat over-simplified version of how SQL Server executes your queries is:

An application sends a “request” to the server, containing some T-SQL statements.

The…

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SQL Server Statistics

The booklet takes a practical, and well-informed approach to a subject that is not always easy to explain or understand.

A Distribution Statistics object is a sampled map of the distribution of data in a table. Such statistics help the Query Optimizer of SQL Server's Database Engine to translate the 'logical' SQL Query into the best strategy for doing all the physical operations of joining, sorting, and selecting the data. Most of the time, this work happens effectively without the database administrator having to be aware of what is going on, but occasionally, if the statistics no longer reflect what is actually in the table, then queries can suddenly run grindingly slow. At this point, the DBA must intervene to correct the problem.

DBAs and Database developers need a reasonable understanding of distribution statistics so as to be prepared for those occasions when things go wrong. SQL Server Distribution Statistics are used by the Query Optimizer to translate what the user has declared to be his wishes for a result, the SQL, into a ‘physical’ strategy that is quick and economical for the database. The relative performance of the various ‘Physical’ strategies for executing the query will vary according to the quantity and distribution of the data within the tables. The Query optimizer uses the statistics to work out the relative merits of the possible strategies. When the statistics are outdated, or missing then queries will miss out on the best strategy for execution and can, at the worst, will get assigned a disastrously poor strategy.

Reading Holger’s booklet is a great way of brushing up on the subject of Statistics and query-optimization. It is reasonably short, and geared to the practitioner rather than the theoretician. It is careful to stick with the things you need to know, and resists the temptation to launch into discourses on the esoteric science of query optimization. For this we are all grateful.

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Amplify’d from www.magicupload.com

SQL Server Statistics

The booklet takes a practical, and well-informed approach to a subject that is not always easy to explain or understand. A Distribution Statistics object is a sampled map of the distribution of data in a table. Such statistics help the Query Optimizer of SQL Server's Database Engine to translate the 'logical' SQL Query into the best strategy for doing all the physical operations of joining, sorting, and selecting the data. Most of the time, this work happens effectively without the database administrator having to be aware of what is going on, but occasionally, if the statistics no longer reflect what is actually in the table, then queries can suddenly run grindingly slow. At this point, the DBA must intervene to correct the problem. DBAs and Database developers need a reasonable understanding of distribution statistics so as to be prepared for those occasions when things go wrong. SQL Server Distribution Statistics are used by the Query Optimizer to translate what the user has declared to be his wishes for a result, the SQL, into a ‘physical’ strategy that is quick and economical for the database. The relative performance of the various ‘Physical’ strategies for executing the query will vary according to the quantity and distribution of the data within the tables. The Query optimizer uses the statistics to work out the relative merits of the possible strategies. When the statistics are outdated, or missing then queries will miss out on the best strategy for execution and can, at the worst, will get assigned a disastrously poor strategy. Reading Holger’s booklet is a great way of brushing up on the subject of Statistics and query-optimization. It is reasonably short, and geared to the practitioner rather than the theoretician. It is careful to stick with the things you need to know, and resists the temptation to launch into discourses on the esoteric science of query optimization. For this we are all grateful.

Download : http://www.fileserve.com/file/S6n4vMK

Read more at www.magicupload.com