– Require the use of strong SSL ciphers, with a minimum 128-bit key length for all connections. The strong- cipher requirement prevents an old or malicious client from forcing use of a weak cipher. 

• MongoDB disables the http interface by default, limiting network exposure (page 327). To enable the interface, see enabled . 

## See also: 

New Authorization Model (page 859), SSL Certificate Hostname Validation (page 860), and Security Checklist (page 431). 

## Query Engine Improvements 

• MongoDB can now use index intersection (page 510) to fulfill queries supported by more than one index. 

• Index Filters (page 69) to limit which indexes can become the winning plan for a query. 

• http://docs.mongodb.org/manual/reference/method/js-plan-cache methods to view and clear the query plans (page 68) cached by the query optimizer. 

• MongoDB can now use count() with hint() . See count() for details. 

## Improvements 

## Geospatial Enhancements 

• 2dsphere indexes version 2 (page 496). 

• Support for MultiPoint (page 554), MultiLineString (page 555), MultiPolygon (page 555), and GeometryCollec- tion (page 556). 

• Support for geospatial query clauses in $or expressions. 

## See also: 

2dsphere Index Version 2 (page 860), $maxDistance Changes (page 863), Deprecated $uniqueDocs (page 863), Stronger Validation of Geospatial Queries (page 863) 

## Index Build Enhancements 

• Background index build (page 508) allowed on secondaries. If you initiate a background index build on a primary , the secondaries will replicate the index build in the background. 

• Automatic rebuild of interrupted index builds after a restart. 

– If a standalone or a primary instance terminates during an index build without a clean shutdown , mongod now restarts the index build when the instance restarts. If the instance shuts down cleanly or if a user kills the index build, the interrupted index builds do not automatically restart upon the restart of the server. 

– If a secondary instance terminates during an index build, the mongod instance will now restart the inter- rupted index build when the instance restarts. 

To disable this behavior, use the --noIndexBuildRetry command-line option. 

• ensureIndex() now wraps a new createIndex command. 

• The dropDups option to ensureIndex() and createIndex is deprecated. 

