With growing memory sizes and memory prices dropping by a factor of 10 every 5 years, data having a "primary home" in memory is now a reality. Main-memory databases eschew many of the traditional architectural pillars of relational database systems that optimized for disk-resident data. The result of these memory-optimized designs are systems that feature several innovative approaches to fundamental issues (e.g., concurrency control, query processing) that achieve orders of magnitude performance improvements over traditional designs. This monograph provides an overview of recent developments in main-memory database systems. It covers five main issues and architectural choices that need to be made when building a high performance main-memory optimized database: data organization and storage, indexing, concurrency control, durability and recovery techniques, and query processing and compilation. The monograph focuses on four commercial and research systems: H-Store/VoltDB, Hekaton, HyPer, and SAPHANA. These systems are diverse in their design choices and form a representative sample of the state of the art in main-memory database systems. It also covers other commercial and academic systems, along with current and future research trends.

This article provides an overview of recent developments in main-memory database systems. With growing memory sizes and memory prices dropping by a factor of 10 every 5 years, data having a "primary home" in memory is now a reality. Main-memory databases eschew many of the traditional architectural pillars of relational database systems that optimized for disk-resident data. The result of these memory-optimized designs are systems that feature several innovative approaches to fundamental issues (e.g., concurrency control, query processing) that achieve orders of magnitude performance improvements over traditional designs. Our survey covers five main issues and architectural choices that need to be made when building a high performance main-memory optimized database: data organization and storage, indexing, concurrency control, durability and recovery techniques, and query processing and compilation. We focus our survey on four commercial and research systems: H-Store/VoltDB, Hekaton, HyPer, and SAP HANA. These systems are diverse in their design choices and form a representative sample of the state of the art in main-memory database systems. We also cover other commercial and academic systems, along with current and future research trends.

Database management is attracting wide interest in both academic and industrial contexts. New application areas such as CAD/CAM, geographic information systems, and multimedia are emerging. The needs of these application areas are far more complex than those of conventional business applications. The purpose of this book is to bring together a set of current research issues that addresses a broad spectrum of topics related to database systems and applications. The book is divided into four parts: - object-oriented databases, - temporal/historical database systems, - query processing in database systems, - heterogeneity, interoperability, open system architectures, multimedia database systems.

With the availability of very large, relatively inexpensive main memories, it is becoming possible to keep large databases resident in main memory. This paper considers the changes necessary to permit a relational database system to take advantage of large amounts of main memory. The authors evaluate AVL vs. B+- tree access methods for main memory databases, hash-based query processing strategies vs. sort-merge, and study recovery issues when most or all of the database fits in main memory. As expected, B+- trees are the preferred storage mechanism unless more than 80-90% of the database fits in main memory. A somewhat surprising result is that hash based query processing strategies are advantageous for large memory situations. Keywords: Access; Algorithms. (Author).

This book explores the implications of non-volatile memory (NVM) for database management systems (DBMSs). The advent of NVM will fundamentally change the dichotomy between volatile memory and durable storage in DBMSs. These new NVM devices are almost as fast as volatile memory, but all writes to them are persistent even after power loss. Existing DBMSs are unable to take full advantage of this technology because their internal architectures are predicated on the assumption that memory is volatile. With NVM, many of the components of legacy DBMSs are unnecessary and will degrade the performance of data-intensive applications. We present the design and implementation of DBMS architectures that are explicitly tailored for NVM. The book focuses on three aspects of a DBMS: (1) logging and recovery, (2) storage and buffer management, and (3) indexing. First, we present a logging and recovery protocol that enables the DBMS to support near-instantaneous recovery. Second, we propose a storage engine architecture and buffer management policy that leverages the durability and byte-addressability properties of NVM to reduce data duplication and data migration. Third, the book presents the design of a range index tailored for NVM that is latch-free yet simple to implement. All together, the work described in this book illustrates that rethinking the fundamental algorithms and data structures employed in a DBMS for NVM improves performance and availability, reduces operational cost, and simplifies software development.

In the last 50 years the world has been completely transformed through the use of IT. We have now reached a new inflection point. Here we present, for the first time, how in-memory computing is changing the way businesses are run. Today, enterprise data is split into separate databases for performance reasons. Analytical data resides in warehouses, synchronized periodically with transactional systems. This separation makes flexible, real-time reporting on current data impossible. Multi-core CPUs, large main memories, cloud computing and powerful mobile devices are serving as the foundation for the transition of enterprises away from this restrictive model. We describe techniques that allow analytical and transactional processing at the speed of thought and enable new ways of doing business. The book is intended for university students, IT-professionals and IT-managers, but also for senior management who wish to create new business processes by leveraging in-memory computing.

"The declining cost of main memory coupled with higher performance expectations has inspired researchers and developers to look into systems with massive amounts of memory, especially for systems with databases. When memory is large enough, an entire database can permanently reside in main memory. These database systems are known as memory resident database or Main Memory DataBase (MMDB) systems. When a database is a main memory resident, systems can achieve significant performance improvements over traditional disk-based database systems by eliminating the overhead required to perform Input/Output operations. However, the problem of crash recovery becomes by far the most challenging issue in MMDB systems, since it can occur frequently and cause a drastic crisis by wiping out the entire content of the database. The kind of crisis that can be encountered due to memory failures, the way to prevent them from occuring in the first place, methods of dealing with them upon their occurance, strategies to make the system more reliable to avoid them in the future, and several other issues like these must be well understood. Approaches to deal with crash recoveries must be sound, well designed, and correctly implemented. The objective of this thesis is to study some of the pioneering works of researchers and developers in the area of MMDB recovery and to perform an in-depth analysis of MMDB recovery issues and approaches taken by several major recovery techniques. The analysis examines the reasons for these techniques, design and architecture, and their benefits and limitations over one another. My independent evaluation of the relative benefits and limitations of each technique coupled with marketablitiy analysis is also presented. The approach used in this study is different from that of other studies that have been published so far in this area. In this study, the reader is given a basic introduction to the topic and then gradually taken through the final stages of analysis and comparison of several recovery techniques."--Author's abstract.