Oracle Berkeley DB Java Edition
Oracle Berkeley DB Java Edition is a open source, embeddable, transactional storage engine written entirely in Java. Like Oracle Berkeley DB, Oracle Berkeley DB Java Edition executes in the address space of the application, without the overhead of client/server communication, allowing developers to store and retrieve information quickly, simply and reliably. Oracle Berkeley DB Java Edition was designed from the ground up in Java. It takes full advantage of the Java environment to simplify development and deployment. The architecture of Oracle Berkeley DB Java Edition supports very high performance and concurrency for both read-intensive and write-intensive workloads.
Berkeley DB Java Edition is designed to offer the same easy storage benefits of Enterprise Java Beans 3.0 (EJB3) and Java Persistence Architecture (JPA) persistence without the need to translate objects into tables.
Relational databases are the most sophisticated tool available to the developer for data storage and analysis, however most persisted object data is never analyzed using ad-hoc SQL queries; it is usually simply retrieved and reconstituted as Java objects. The overhead of using a sophisticated analytical storage engine is wasted on this basic task of object retrieval. The full analytical power of the relational model is not required to efficiently persist Java objects. In many cases, it is unnecessary overhead. In contrast, Berkeley DB Java Edition does not have the overhead of an ad-hoc query language like SQL, and so does not incur this penalty.
The result is faster storage, lower CPU and memory requirements, and a more efficient development process. Despite the lack of an ad-hoc query language, Berkeley DB Java Edition can access Java objects in an ad-hoc manner, and it does provide transactional data storage and indexed retrieval, as you would expect from any database. The difference is that it does this in a small, efficient, and easy-to-manage package. Using the Direct Persistence Layer (DPL), Java developers can quickly and easily persist and retrieve inter-related groups of Java objects with confidence, speed, and a fraction of the complexity and overhead of a comparable ORM solution.
Berkeley DB Java Edition was designed from the ground up in Java. It takes full advantage of the Java environment. The API provides a Java Collections-style interface, as well as a programmatic interface similar to the Berkeley DB API. The architecture of Berkeley DB Java Edition supports high performance and concurrency for both read-intensive and write-intensive workloads.
Berkeley DB Java Edition is different from all other Java databases available today. Berkeley DB Java Edition is not a relational engine built in Java. It is a Berkeley DB-style embedded store, with an interface designed for programmers, not DBAs. The architecture is based on a log-based, no-overwrite storage system, enabling high concurrency and speed while providing ACID transactions and record-level locking. Berkeley DB Java Edition efficiently caches most commonly used data in memory, without exceeding application-specified limits. In this way Berkeley DB Java Edition works with an application to use available JVM resources while providing access to very large data sets.
J2EE is a central part of many enterprise deployments of Java. Berkeley DB Java Edition fits into the J2EE architecture by implementing three key APIs within J2EE. At its core, Berkeley DB Java Edition is a transactional database. Within a J2EE application server, many different subsystems must coordinate and work together in a transactional manner. By implementing the Java Transaction API (JTA), Berkeley DB Java Edition functions as a managed transactional resource within the application server. Berkeley DB Java Edition also implements the J2EE Connector Architecture (JCA) to ease integration into application servers. Finally, once integrated and performing transactional operations, most applications will require some ability to manage a service. Berkeley DB Java Edition exports information and services using the Java Management Extensions (JMX). In concert JTA, JCA and JMX allow Berkeley DB Java Edition to operate to its fullest and in a predictable manner in J2EE-based solutions.
Berkeley DB Java Edition supports replication over multiple systems, enabling applications to scale massively with low latency and provide fault tolerance for high availability solutions. This technique works by having all updates go to a designated master, which distributes changes automatically to a set of replicas. The read workload can be spread across the replicas, and new replicas can join the group at any time to scale the system. If any replica fails, the remaining replicas can take over for it. If a master node fails, the replicas will hold an election and designate a new master. Once the new master has been chosen, all of the replicas synchronize with it and move forward with normal processing with no interruption in service. The master-failover process generally takes only a fraction of a second and read-requests can be serviced by replicas during that fail-over period ensuring zero downtime.
Berkeley DB Java Edition provides robust storage services for any Java application requiring high performance, transactional integrity and recoverability.
Key Features
Data Storage
Berkeley DB Java Edition stores data quickly and easily without much of the overhead found in other databases. Berkeley DB Java Edition is a single JAR file that runs in the same JVM as your application, so there is no remote server. A local cache keeps the most active data in memory, avoiding costly disk access, and bounds the usage of JVM memory to a predictable amount.
- Local, in-process data storage
- Schema-neutral, application native data storage
- Keyed and sequential data retrieval
- Easy-to-use Java Collections API
- Direct Persistence Layer (DPL) for accessing Java objects
- Schema evolution of DPL classes
- Single process, multi-threading model
- Record level locking for high concurrency
- Support for secondary indexes
- In-memory, on disk or both
- Configurable background cleaner threads re-organize data and optimize disk use
Transactions
Berkeley DB Java Edition stores data reliably and ensures data integrity. In the event of a system failure, Berkeley DB Java Edition will recover transactional data and reset the system to a functional and consistent state from log and database information.
- Full ACID compliance
- Selectable isolation levels and durability guarantees, configurable on a per-transaction basis
- Managed transactions using the Java Transaction API (JTA)
- J2EE application server integration using J2EE Connector Architecture(JCA)
- Auditing, monitoring, and administration using the Java Management Extensions (JMX)
- Catastrophic and routine failure recovery modes
- Timeout based deadlock detection
- Hot and cold backups, log file compaction, and full database dumps
Deployment
Berkeley DB Java Edition is highly portable, very flexible and easy to integrate. It was designed from day one as a pure Java product taking full advantage of the Java environment. As a single Java Archive (JAR) file, it runs within the JVM running your application. Berkeley DB Java Edition was designed to serve the large and growing Java community with a enterprise-grade, pure Java, data storage solution.
- 100% pure Java for portability and ease of development
- Single JAR file - easy to install, runs in the same JVM as the application
- Java 1.4.2 or later Standard Edition JVM required
- Programmatic administration and management
- Zero human administration
- API for routine administrative functions
- Small footprint 820KB
- Scalable to terabytes of data, millions of records
- Source code, test suite included
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