You can remove a specific index from a collection. You may need to drop an index if you see a negative performance impact, want to replace it with a new index, or no longer need the index.
To drop an index, use one of the following shell methods:
| Method | Description |
|---|---|
Drops a specific index from the collection. | |
Drops all removable indexes from the collection or an array of indexes, if specified. |
About this Task
You can drop any index except the default index on the _id field.
To drop the _id index, you must drop the entire collection.
If you drop an index that's actively used in production, you may experience performance degradation. Before you drop an index, consider hiding the index to evaluate the potential impact of the drop.
Before You Begin
To drop an index, you need its name. To get all index names for a
collection, run the getIndexes() method:
db.<collection>.getIndexes()Procedures
After you identify which indexes to drop, use one of the following drop methods for the specified collection:
Drop a Single Index
To drop a specific index, use the dropIndex() method and specify the index name:
db.<collection>.dropIndex("<indexName>")Drop Multiple Indexes
To drop multiple indexes, use the dropIndexes() method and specify an array of index names:
db.<collection>.dropIndexes( [ "<index1>", "<index2>", "<index3>" ] )Drop All Indexes Except the _id Index
To drop all indexes except the _id index, use
the dropIndexes() method:
db.<collection>.dropIndexes()Results
After you drop an index, the system returns information about the status of the operation.
Example output:
...
{ "nIndexesWas" : 3, "ok" : 1 }
...The value of nIndexesWas reflects the number of indexes before
removing an index.
To confirm that the index was dropped, run the
db.collection.getIndexes() method:
db.<collection>.getIndexes()The dropped index no longer appears in the getIndexes() output.
Learn More
- To learn more about managing your existing indexes, see Manage Indexes.
- To learn how to remove an index in MongoDB Compass, see Manage Indexes in Compass.