WiredTiger

WiredTiger is a high-performance, scalable storage engine that originated as an open-source project developed by WiredTiger, Inc. It gained prominence for its focus on concurrency, data compression, and crash resilience on modern multi-core hardware. In 2014, MongoDB, Inc. acquired the company and integrated WiredTiger as a storage engine option for the MongoDB ecosystem. It is widely used for workloads that require efficient utilization of CPU and I/O resources and for reducing storage footprints through compression.

Technically, WiredTiger employs multi-version concurrency control (MVCC) and per-document locking to improve write throughput and reduce contention compared with finer-grained locking schemes. It uses a B-tree based data layout and separates on-disk representation from in-memory caches, providing configurable caching, indexing, and I/O behavior. The engine supports multiple data compression options, most notably Snappy and Zlib, with support for additional algorithms in newer releases. For durability and crash recovery, WiredTiger uses a write-ahead log (journal) and checkpoints to ensure data integrity after unexpected shutdowns.

WiredTiger became the default storage engine for MongoDB with MongoDB 3.2, replacing the earlier MMAPv1 engine and enabling better concurrent performance for a wide range of workloads. Although it is closely associated with MongoDB, the WiredTiger library is designed to be usable as a standalone storage engine in other projects that integrate its codebase. Ongoing development continues to enhance performance, compression options, and reliability across diverse hardware configurations and workloads.