MongoDB 4.4 is now generally available for production deployments. MongoDB 4.4 delivers the features and enhancements most demanded by you. We think of 4.4 as “user-driven engineering”, building on the MongoDB 4.x release family as an ideal foundation for modern workloads. The result is a database that enables you to build transactional, operational, and analytic applications faster and more efficiently. You can scale them out globally, with the flexibility to define and refine data distribution at any time as your requirements evolve. All while giving you some of the most sophisticated latency, resilience, and security controls anywhere. Download MongoDB today, or try MongoDB 4.4 in the cloud with Atlas in minutes.
Here are the highlights of what’s new and improved in MongoDB 4.4:
MongoDB Query Language
- Union: Enhancing the power of the MongoDB Query Language, you can now combine results from multiple collections and aggregation pipelines into a single result set in the database, allowing your users to easily blend data from multiple sources for deeper exploration and analysis.
- Custom Aggregation Expressions: you can extend the functionality of MongoDB for your specific use cases by defining your own custom expressions in JavaScript and now have them execute natively within the database engine as part of an aggregation pipeline.
- New aggregation expressions: simplifying your code, it’s now easier to search and manipulate strings and evaluate the first and last elements of an array. To simplify schema analysis and performance optimization, you can use new binary expressions to return the size of binary objects in your documents
Scale-Out Flexibility & Performance
- Refinable shard keys: With the ability to define and refine your shard keys at any time, you can now adapt data distribution across your cluster as your database grows and applications evolve, without impacting system availability.
- Compound hashed shard keys: By adding support for hashing any single field in a compound shard key, you get higher database throughput by more evenly distributing load across shards, without losing data locality or creating hot shards as your applications scale.
- Hedged Reads: To minimize p95 and p99 latencies, the MongoDB query router is configured by default to submit read requests with read preference “nearest” to multiple replicas in a sharded cluster, returning results to the client as soon as the quickest node responds.
Resilience and Security
- Mirrored Reads: Reducing the user impact of replica set elections, you can pre-warm the caches of secondaries by mirroring a percentage of reads to them in advance of stepping down the primary.
- Resumable Initial Sync: The initial sync process now automatically resumes after encountering transient network errors, making it easier and faster to scale-out by adding new replicas to your cluster or recover nodes that have fallen too far behind other members
For more information about MongoDB 4.4, please review our complete release notes and download our Guide to What’s New.
Last but not least, we would like to acknowledge the following community members who have contributed to this release: Xavier Guihot, Frederick Zhang, Roberth Godoy, Markus Schroder, Łukasz Walukiewicz, McKittrick Swindle, Graeme Yeates, Johan Suárez, Rui Ribeiro, James Harvey, Andres Kalle, Ryan Schmidt, Łukasz Karczewski, Adam Flynn, Ralph Seichter, Marek Kresnicki, David Lynch, Yohei Tamura, Barak Gilboa, David Bartley, Jared D. Cottrell, Dan Dascalescu, Michael Hofer, Anton Papp, Artem, Mohammed Sulthan, Mitar, Ricardo Bánffy, Adam Comerford, David Schneider, LinGao, lipengchong, Piyush Kumar, Henry Bettany, Ralf Strobel, jackin huang, Greg Studer, Alexey Glukhov, Devendra Chauhan, John Arbash Meinel, Connecting Media, Gilad Peleg, Travis Redman, Chad Kreimendahl, Alice Classy, Remon van Vliet, Rohit Kumar, Sam Tolmay, Ofer Cohen, zhaoliwei
MongoDB 4.4 Release Notes | Changelog | Downloads
– The MongoDB Team