We are pleased to announce the release of MongoDB version 2.2. This release includes over 1,000 new features, bug fixes, and performance enhancements, with a focus on improved flexibility and performance. For additional details on the release:
The Aggregation Framework is available in its first production-ready release as of 2.2. The aggregation framework makes it easier to manipulate and process documents inside of MongoDB, without needing to useMap Reducez,/span>, or separate application processes for data manipulation.
See the aggregation documentation for more information.
Additional “Data Center Awareness” Functionality
2.2 also brings a cluster of features that make it easier to use MongoDB for larger more geographically distributed contexts. The first change is a standardization of read preferences across all drivers and sharded (i.e. mongos) interfaces. The second is the addition of “tag aware sharding,” which makes it possible to ensure that data in a geographically distributed sharded cluster is always closest to the application that will use that data the most.
Improvements to Concurrency
v2.2 eliminates the global lock in the mongod process. Locking is now per database. In addition a new subsystem avoids locks under most page-fault events; thus concurrency improves even on systems with a single database. Parallelism in application of writes on secondaries is enhanced also. See this video for more details.
- Eliot and the 10gen/MongoDBteam