> For the complete MongoDB documentation index, see www.mongodb.com/docs/llms.txt

# Manage Indexes

MongoDB Compass Readonly Edition will be deprecated in a future release. To replicate the read-only behavior in a standard Compass edition, assign users [`read`](https://www.mongodb.com/docs/manual/reference/built-in-roles.md#mongodb-authrole-read) access at the database level and enable the [readOnly](https://www.mongodb.com/docs/compass/settings/read-only.md#std-label-compass-read-only) option in Compass.

Indexes are special data structures that improve query performance. Indexes store a portion of a collection's data in an easy-to-traverse form. The index stores the value of a specific field or set of fields, ordered by the value of the field.

To improve query performance, build indexes on fields that appear often in queries and for all operations that [sort by a field.](https://www.mongodb.com/docs/compass/query/sort.md#std-label-compass-query-bar-sort)

- Queries on an indexed field can use the index to limit the number of documents that must be scanned to find matching documents.

- Sort operations on an indexed field can return documents pre-sorted by the index.

To learn more about indexes, see [Indexes.](https://www.mongodb.com/docs/manual/indexes/)

**Note: Considerations**

Indexes have some negative performance impact on write operations. For collections with high write-to-read ratio, indexes are expensive since each insert must also update any indexes. For a detailed list of considerations for indexes, see [Operational Considerations for Indexes.](https://www.mongodb.com/docs/manual/data-modeling/best-practices.md#std-label-data-model-indexes)

## Indexes Tab

The Indexes tab lists the existing indexes for a collection.

To access the Indexes tab for a collection, click on the collection on the left hand pane and select the Indexes tab.

**Warning:**

The Indexes tab only shows Usage metrics for the node that Compass is currently connected to. For more comprehensive index usage statistics, run the [`$indexStats`](https://www.mongodb.com/docs/manual/reference/operator/aggregation/indexStats.md#mongodb-pipeline-pipe.-indexStats) aggregation stage on each node in your cluster.

![Indexes view](/images/compass/indexes-view.png)

For each index, Compass displays the following information:

| Name and Definition | The name of the index and keys. |
| --- | --- |
| Type | Regular, text, geospatial or hashed index. |
| Size | How large the index is. |
| Usage | Number of times the index has been used in a lookup since the time the index was created or the last server restart. WARNING: The Usage metrics show index usage statistics only for the node that Compass is currently connected to and should only be used for informational purposes. For more comprehensive index usage statistics, run the [`$indexStats`](https://www.mongodb.com/docs/manual/reference/operator/aggregation/indexStats.md#mongodb-pipeline-pipe.-indexStats) aggregation stage on each node. |
| Properties | Any special properties (such as uniqueness, partial) of the index. |

## Limitations

- Creating, hiding, and dropping indexes is not permitted in MongoDB Compass Readonly Edition.

- Do not create indexes on encrypted fields. Creating indexes on encrypted fields that use Queryable Encryption negatively affect performance. Instead, you can create an index on the `__safeContent__` field to support queries on encrypted fields.

- You can manage Atlas Search indexes in Compass if your deployment is local, has an Atlas cluster tier of M10 or larger, and runs MongoDB 7.0 or higher.

  **Tip:**

  For clusters running an earlier version of MongoDB, you can manage your Atlas Search indexes using the Atlas UI, the [Atlas CLI](https://www.mongodb.com/docs/atlas/cli/current/), or the [Atlas Administration API.](https://www.mongodb.com/docs/atlas/api/atlas-admin-api.md#std-label-atlas-admin-api)

## Create an Index

1. Open the index creation dialog

   From the [Indexes](https://www.mongodb.com/docs/compass/indexes.md#std-label-compass-indexes-tab) tab, click the Create
   Index button.

2. Add fields to the index

   Specify an index key.

   - To specify an existing document field as an index key, select the field from the dropdown list.

   - To specify a field that does not exist in any document as an index key, enter the field name in the input box.

   - To create a [compound index](https://www.mongodb.com/docs/manual/core/index-compound/), click the  icon next to the index type dropdown.

   Use the dropdown to the right of each field name to specify the index type. You can specify one of the following types:

   - Ascending

   - Descending

   - 2dsphere

   - Text

   **See also:**

   To learn how to specify a wildcard index, see [Create a Wildcard Index.](https://www.mongodb.com/docs/compass/indexes.md#std-label-compass-wildcard-index)

3. Optional. Specify index options

   Compass supports the following index options:

   | Option | Description | More Information |
   | --- | --- | --- |
   | Create unique index | Ensure that the indexed fields do not store duplicate values. | [Unique Indexes](https://www.mongodb.com/docs/manual/core/index-unique/) |
   | Index name | Specify a name for the index. | [Specify an Index Name](https://www.mongodb.com/docs/manual/core/indexes/create-index/specify-index-name.md#std-label-specify-index-name) |
   | Create a TTL (Time to Live) index | Delete documents automatically after a specified number of seconds since the indexed field value. | [TTL Indexes](https://www.mongodb.com/docs/manual/core/index-ttl/) |
   | Partial filter expression | Index only the documents which match the specified filter expression. For example: The following partial filter expression only indexes documents where the `timezone` field exists: `{ "timezone": { "$exists": true } }` | [Partial Indexes](https://www.mongodb.com/docs/manual/core/index-partial/) |
   | Wildcard projection | Support unknown or arbitrary fields which match the specified projection in the index. To use a wildcard projection, set your index field name to  `$**`. This directs Compass to use all fields in the document (excluding `_id`). For example: Consider the following wildcard projection document: `{
     "product_attributes.elements" : 1,
     "product_attributes.resistance" : 1
   }` If your index field name is `$**`, your index only includes the values of the fields in that projection. | [Create a Wildcard Index](https://www.mongodb.com/docs/compass/indexes.md#std-label-compass-wildcard-index) |
   | Use custom collation | Create a custom collation for the index by typing or pasting the collation document in the text box. | [Collation Document](https://www.mongodb.com/docs/manual/reference/collation/#collation-document) |

4. Click Create Index.

### Create an Atlas Search Index

Atlas Search indexes let you query data in [Atlas Search](https://www.mongodb.com/docs/atlas/atlas-search/). For more information, see [Create and Manage a MongoDB Search Index.](https://www.mongodb.com/docs/compass/indexes/create-search-index.md#std-label-compass-create-search-index)

### Create an Atlas Vector Search Index

Atlas Vector Search indexes enable you to index vector data *and* other data types, which facilitates semantic searches on the indexed fields. For more information, see [Create a MongoDB Vector Search Index.](https://www.mongodb.com/docs/compass/indexes/create-vector-search-index.md#std-label-compass-create-vector-search)

### Create a Wildcard Index

You can create [wildcard indexes](https://www.mongodb.com/docs/manual/core/index-wildcard/) to support queries against unknown or arbitrary fields. To create a wildcard index in Compass, manually type the wildcard index field (`<field>.$**`) into the Select a field name input.

**Example:**

Consider a collection where documents contain a `userMetadata` object. The fields within the `userMetadata` object may vary between documents.

You can create a wildcard index on `userMetadata` to account for all potential fields within the object. Type the following into the Select a field name input:

```javascript
userMetadata.$**
```

Specify a type (`ascending` or `descending`) for your wildcard index, then click Create Index.

Compass shows the type of your new index as Wildcard.

## Hide or Unhide an Index

You can [hide an index](https://www.mongodb.com/docs/manual/core/index-hidden/) from the query planner to evaluate the potential impact of dropping an index without actually dropping the index.

1. Hover over the index.

   From the Indexes tab, hover over the index you want to hide.

2. Click the Hide Index button.

   Click the closed-eye icon on the right that appears when you hover over your selected index.

3. Click Confirm.

   In the dialog box, confirm the index you want to hide. After you confirm your selection, a Hidden badge appears under the Properties column.

   To unhide your index, repeat steps 1-3. After you unhide your index, Compass removes the Hidden badge from the Properties column.

## Drop an Index

1. Click the trash can icon for the index to drop.

   From the [Indexes](https://www.mongodb.com/docs/compass/indexes.md#std-label-compass-indexes-tab) tab, to delete an index, click on the trash can icon for that index. A confirmation dialog appears.

2. Confirm the index to delete.

   In the dialog, enter the name of the index to delete.

3. Click Drop to drop the index.