Database Reference
In-Depth Information
9 An Overview of the
NoSQL World
Liang Zhao, Sherif Sakr, and Anna Liu
CONTENTS
9.1 Introduction .................................................................................................. 288
9.2 NoSQL Key Systems .................................................................................... 291
9.2.1 Google: Bigtable ............................................................................... 291
9.2.2 Yahoo: PNUTS ................................................................................. 293
9.2.3 Amazon: Dynamo ............................................................................. 294
9.3 NoSQL Open Source Projects ...................................................................... 296
9.4 Database-as-a-Service .................................................................................. 299
9.4.1 Google Datastore .............................................................................. 299
9.4.2 Amazon: S3/SimpleDB/Amazon RDS ............................................. 301
9.4.3 Microsoft SQL Azure ....................................................................... 303
9.5 Web Scale Data Management: Tradeoffs ..................................................... 305
9.6 Challenges of the New Wave of NoSQL Systems ........................................ 308
9.6.1 True Elasticity ................................................................................... 308
9.6.2 Data Replication and Consistency Management .............................. 309
9.6.3 SLA Management ............................................................................. 312
9.6.4 Transaction Support .......................................................................... 314
9.7 Discussion and Conclusions .......................................................................... 317
References .............................................................................................................. 320
Over the past decade, rapidly growing Internet-based services such as e-mail, blog-
ging, social networking, search, and e-commerce have substantially redefined the
way consumers communicate, access contents, share information and purchase prod-
ucts. Relational database management systems (RDBMS) have been considered as
the one-size-fits-all solution for data persistence and retrieval for decades. However,
the ever-increasing need for scalability and new application requirements have cre-
ated new challenges for traditional RDBMS. Recently, a new generation of low-cost,
high-performance database software, aptly named as NoSQL (Not Only SQL), has
emerged to challenge the dominance of RDBMS. The main features of these systems
include ability to horizontally scale, supporting weaker consistency models, using flex-
ible schemas and data models and supporting simple low-level query interfaces. In this
chapter, we explore the recent advancements and the new approaches of web-scale
data management. We discuss the advantages and disadvantages of several recently
introduced approaches and its suitability to support certain class of applications and
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