Index Types

Single Field Index

Single field indexes collect and sort data from a single field in each document in a collection.

This image shows an index on a single field, score:

To learn more, see Single Field Indexes.

Compound Index

Compound indexes collect and sort data from two or more fields in each document in a collection. Data is grouped by the first field in the index and then by each subsequent field.

For example, the following image shows a compound index where documents are first grouped by userid in ascending order (alphabetically). Then, the scores for each userid are sorted in descending order:

To learn more, see Compound Indexes.

Multikey Index

Multikey indexes collect and sort data stored in arrays.

You do not need to explicitly specify the multikey type. When you create an index on a field that contains an array value, MongoDB automatically sets the index to be a multikey index.

This image shows a multikey index on the addr.zip field:

To learn more, see Multikey Indexes.

Geospatial Index

Geospatial indexes improve performance for queries on geospatial coordinate data. To learn more, see Geospatial Indexes.

MongoDB provides two types of geospatial indexes:

• 2d indexes that use planar geometry to return results.

• 2dsphere indexes that use spherical geometry to return results.

Text Index

Text indexes support text search queries on fields containing string content.

To learn more, see Text Indexes on Self-Managed Deployments.

Hashed Index

Hashed indexes support hashed sharding. Hashed indexes index the hash of the value of a field.

To learn more, see Hashed Indexes.

Clustered Index

Clustered indexes specify the order in which clustered collections store data. Collections created with a clustered index are called clustered collections.

To learn how to create a collection with a clustered index, see Clustered Collection Examples.