db.collection.dropIndexes()
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Definition
db.collection.dropIndexes()
Important
mongosh Method
This page documents a
mongosh
method. This is not the documentation for database commands or language-specific drivers, such as Node.js.For the database command, see the
dropIndexes
command.For MongoDB API drivers, refer to the language-specific MongoDB driver documentation.
Drops the specified index or indexes (except the index on the
_id
field and the last remaining shard key index) from a collection.You can use the method to:
Drop all but the
_id
index from a collection.db.collection.dropIndexes() Drop a specified index from a collection. To specify the index, you can pass the method either:
The index specification document (unless the index is a text index in which case, use the index name to drop):
db.collection.dropIndexes( { a: 1, b: 1 } ) The index name:
db.collection.dropIndexes( "a_1_b_1" ) Tip
To get the names of the indexes, use the
db.collection.getIndexes()
method.
Drop specified indexes from a collection. To specify multiple indexes to drop, pass the method an array of index names:
db.collection.dropIndexes( [ "a_1_b_1", "a_1", "a_1__id_-1" ] ) If the array of index names includes a non-existent index, the method errors without dropping any of the specified indexes.
Tip
To get the names of the indexes, use the
db.collection.getIndexes()
method.
The
db.collection.dropIndexes()
method takes the following optional parameter:ParameterTypeDescriptionindexes
string or document or array of stringsOptional. Specifies the index or indexes to drop.
To drop all but the _id index from the collection, omit the parameter.
To drop a single index, specify either the index name, the index specification document (unless the index is a text index), or an array of the index name. To drop a text index, specify the index name or an array of the index name instead of the index specification document.
To drop multiple indexes, specify an array of the index names.
Compatibility
This method is available in deployments hosted in the following environments:
MongoDB Atlas: The fully managed service for MongoDB deployments in the cloud
Note
This command is supported in all MongoDB Atlas clusters. For information on all commands, see Unsupported Commands.
MongoDB Enterprise: The subscription-based, self-managed version of MongoDB
MongoDB Community: The source-available, free-to-use, and self-managed version of MongoDB
Behavior
Starting in MongoDB 6.0, db.collection.dropIndexes()
raises an error if you attempt
to use it to remove the last remaining shard key compatible index.
Passing "*"
to db.collection.dropIndexes()
drops all indexes except
the _id
index and the last remaining shard key compatible index,
if one exists.
Starting in MongoDB 5.2, you can use db.collection.dropIndexes()
to drop existing
indexes on the same collection even if there is a build in progress on
another index. In earlier versions, attempting to drop a different
index during an in-progress index build results in a
BackgroundOperationInProgressForNamespace
error.
Kill related queries only
The dropIndexes()
operation only kills queries that are using the index being
dropped. This may include queries considering the index as part of
query planning.
Resource Locking
db.collection.dropIndexes()
obtains an exclusive lock on the specified collection
for the duration of the operation. All subsequent operations on the
collection must wait until db.collection.dropIndexes()
releases the
lock.
Index Names
If the method is passed an array of index names that includes a non-existent index, the method errors without dropping any of the specified indexes.
_id
Index
You cannot drop the default index on the _id
field.
text Indexes
To drop a text index, specify the index name instead of the index specification document.
Stop In-Progress Index Builds
If an index specified to db.collection.dropIndexes()
is still building, db.collection.dropIndexes()
attempts
to stop the in-progress build. Stopping an index build has the same effect as
dropping the built index.
For replica sets, run db.collection.dropIndexes()
on the primary.
The primary stops the index build and creates an associated
"abortIndexBuild" oplog entry. Secondaries which replicate
the "abortIndexBuild" oplog entry stop the in-progress index build and
discard the build job. See Index Build Process for detailed
documentation on the index build process.
Use currentOp
to identify the index builds associated with
a createIndexes
or db.collection.createIndexes()
operation. See Active Indexing Operations for an example.
Hidden Indexes
MongoDB offers the ability to hide or unhide indexes from the query planner. By hiding an index from the planner, you can evaluate the potential impact of dropping an index without actually dropping the index.
If after the evaluation, the user decides to drop the index, you can drop the hidden index; i.e. you do not need to unhide it first to drop it.
If, however, the impact is negative, the user can unhide the index instead of having to recreate a dropped index. And because indexes are fully maintained while hidden, the indexes are immediately available for use once unhidden.
For more information on hidden indexes, see Hidden Indexes.