Last checked and updated on 05 Jun 2026
What Is New in MongoDB 1.1
MongoDB 1.1 delivers a significant upgrade focused on performance and operational stability. This release introduces new indexing capabilities and addresses a number of critical bugs from the previous version.
| Category | Key Changes |
|---|---|
| New Features | Compound Index Support, Index Build Timing Option |
| Improvements | Memory Mapped File Performance, Windows Service Support |
| Bug Fixes | Replication, Sharding, Windows Crashes, .bson Tools |
How does compound indexing work in 1.1?
Version 1.1 adds support for compound indexes, letting you create an index on multiple fields. This is a game-changer for queries that filter or sort on more than one key, drastically cutting down query times.
You build them directly from the shell. The order of fields matters because it affects which queries can use the index efficiently.
db.things.ensureIndex({ a: 1, b: -1 })What performance improvements were made?
The handling of memory mapped files got a major boost. This directly improves overall database performance, making read and write operations faster and more efficient under load.
For Windows users, MongoDB can now be installed as a proper service. This makes it much easier to manage deployments in production environments without manual workarounds.
Which critical bugs were fixed?
The team squashed several nasty issues. Key fixes include problems with replication, sharding migration, and multiple crashes specific to Windows systems that were causing headaches.
The data tools were also patched. Both mongodump and mongorestore had bugs that corrupted .bson files during dump/restore operations, which is now resolved.
FAQ
Should I upgrade to MongoDB 1.1 for the compound indexes alone?
Absolutely. If your queries involve multiple fields, compound indexes are a massive win for performance. The other stability fixes are a strong reason to upgrade as well.
Does the Windows service support mean it's production-ready on Windows?
It's a big step forward. The service support and crash fixes make running it on Windows far more stable than in 1.0, making it a viable option for production.
What's the deal with the index build timing option?
It gives you control. You can choose to build indexes in the background, which prevents the database from locking up and becoming unresponsive during the process on large collections.
Were there any authentication or security changes?
No, this release was focused on core database functionality, performance, and bug fixes. The security model remains the same as in previous versions.
I use sharding; what fixes should I look for?
Check the fixes related to sharding migration. The update resolves issues where migrations could fail or get stuck, which improves the reliability of your sharded cluster.