Book Image

Amazon SimpleDB Developer Guide

Book Image

Amazon SimpleDB Developer Guide

Overview of this book

SimpleDB is a highly scalable, simple-to-use, and inexpensive database in the cloud from Amazon Web Services. But in order to use SimpleDB, you really have to change your mindset. This isn't a traditional relational database; in fact it's not relational at all. For developers who have experience working with relational databases, this may lead to misconceptions as to how SimpleDB works.This practical book aims to address your preconceptions on how SimpleDB will work for you. You will be quickly led through the differences between relational databases and SimpleDB, and the implications of using SimpleDB. Throughout this book, there is an emphasis on demonstrating key concepts with practical examples for Java, PHP, and Python developers.You will be introduced to this massively scalable schema-less key-value data store: what it is, how it works, and why it is such a game-changer. You will then explore the basic functionality offered by SimpleDB including querying, code samples, and a lot more. This book will help you deploy services outside the Amazon cloud and access them from any web host.You will see how SimpleDB gives you the freedom to focus on application development. As you work through this book you will be able to optimize the performance of your applications using parallel operations, caching with memcache, asynchronous operations, and more.
Table of Contents (16 chapters)
Amazon SimpleDB Developer Guide
Credits
Foreword
About the Authors
About the Reviewers
Preface

BoxUsage


Each request made to SimpleDB returns a BoxUsage value as part of the response. This response indicates the amount of system resources that were utilized by that specific operation. This value can be used to figure out the cost of making any kind of a request to SimpleDB, and can thus be used to tune queries.

Note

The higher the BoxUsage value, the more expensive the request made to SimpleDB.

The value of BoxUsage is always consistent for operations such as creating a domain, but in the case of Select requests that are usually used for querying SimpleDB, the BoxUsage values are normalized and are supposed to reflect two parameters that categorize your SimpleDB data:

  • Your dataset and the data that is contained within it

  • The complexity of the query that you are making to SimpleDB for retrieving your data

This enables one to optimize and tune their queries using the BoxUsage value. This value is not affected by what other users are doing when utilized in the context of making Select queries...