Berkeley DB is a database engine that offers developers with fast, reliable, local persistence with zero administration. Berkeley DB is a library that links directly into your application. Your application makes simple function calls, rather than sending messages to a remote server, eliminating the performance penalty of client-server architectures. Berkeley DB stores data in application native format, as simple key/value pairs, eliminating the need for translation or mapping. Berkeley DB eliminates the overhead of SQL query processing, enabling applications with predictable access patterns to run faster. Berkeley DB is the ideal choice for static queries over dynamic data, while traditional relational databases are well suited for dynamic queries over static data.

Berkeley DB delivers the same robust data storage features as traditional, relational database systems, such as ACID transactions and recovery; locking, multiple processes and multi-threading for high concurrency; hot and cold backup; and single-master replication for high availability applications. Berkeley DB can manage databases in memory, on disk or both. Berkeley DB is designed to run in a completely unattended fashion, so all runtime administration is programmatically controlled by the application, not by a human administrator. It has been designed to be simple, fast, small and reliable.

Berkeley DB 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 the master fails, the application can call for an election or simply designate a new master. Once the new master has been chosen, all of the replicas synchronize with the new master and move forward with normal processing with no interruption in service.

Berkeley DB is very flexible and puts developers in control of many aspects of its behavior, which allows it to be used across a wide range of applications and as a replacement for custom, home-grown solutions. For example, developers can control how resources are allocated, the amount of memory dedicated to caching records, the on-disk storage structure used for individual tables, durability and isolation guarantees, and replication policies. It includes full source code for easier porting, integration, debugging and optimization.

Berkeley DB provides very fast, reliable and scalable persistence for applications that need to store data locally, run unattended without interruption, and access data in a predictable fashion.

Features:

• Local, in-process data storage
• Schema-neutral, application native data format
• Indexed and sequential retrieval (Btree, Queue, Recno, Hash)
• Multiple processes per application and multiple threads per process
• Fine grained and configurable locking for highly concurrent systems
• Support for secondary indexes
• In-memory, on disk or both
• Online Btree compaction
• Online Btree disk space reclamation
• Online abandoned lock removal
• On disk data encryption (AES)
• Records up to 4GB and tables up to 256TB

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