db.collection.deleteMany() (mongosh method)

MongoDB with drivers

This page documents a mongosh method. To see the equivalent method in a MongoDB driver, see the corresponding page for your programming language:

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Definition

db.collection.deleteMany()

Removes all documents that match the filter from a collection.

Returns:	A document containing: A boolean `acknowledged` as `true` if the operation ran with write concern or `false` if write concern was disabled `deletedCount` containing the number of deleted documents

Note

If you are deleting all documents in a large collection, it may be faster to drop the collection and recreate it. Before dropping the collection, note all indexes on the collection. You must recreate any indexes that existed in the original collection. If the original collection was sharded, you must also shard the recreated collection.

For more information on dropping a collection, see db.collection.drop().

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 Atlas support for 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

Syntax

The deleteMany() method has the following syntax:

db.collection.deleteMany(
   <filter>,
   {
      writeConcern: <document>,
      collation: <document>,
      hint: <document>|<string>,
      maxTimeMS: <int>,
      let: <document>
   }
)

Parameter

Type

Description

filter

document

Specifies deletion criteria using query operators.

To delete all documents in a collection, pass in an empty document ({ }).

writeConcern

document

Optional. A document expressing the write concern. Omit to use the default write concern.

Do not explicitly set the write concern for the operation if run in a transaction. To use write concern with transactions, see Transactions and Write Concern.

collation

document

Optional.

Specifies the collation to use for the operation.

Collation allows users to specify language-specific rules for string comparison, such as rules for lettercase and accent marks.

The collation option has the following syntax:

collation: {
    locale: <string>,
    caseLevel: <boolean>,
    caseFirst: <string>,
    strength: <int>,
    numericOrdering: <boolean>,
    alternate: <string>,
    maxVariable: <string>,
    backwards: <boolean>
 }

When specifying collation, the locale field is mandatory; all other collation fields are optional. For descriptions of the fields, see Collation Document.

If the collation is unspecified but the collection has a default collation (see db.createCollection()), the operation uses the collation specified for the collection.

If no collation is specified for the collection or for the operations, MongoDB uses the simple binary comparison used in prior versions for string comparisons.

You cannot specify multiple collations for an operation. For example, you cannot specify different collations per field, or if performing a find with a sort, you cannot use one collation for the find and another for the sort.

hint

document

Optional. A document or string that specifies the index to use to support the query predicate.

The option can take an index specification document or the index name string.

If you specify an index that does not exist, the operation errors.

For an example, see Specify hint for Delete Operations.

maxTimeMS

integer

Optional. Specifies the time limit in milliseconds for the delete operation to run before timing out.

let

Document

Optional.

Specifies a document with a list of variables. This allows you to improve command readability by separating the variables from the query text.

The document syntax is:

{
  <variable_name_1>: <expression_1>,
  ...,
  <variable_name_n>: <expression_n>
}

The variable is set to the value returned by the expression, and cannot be changed afterwards.

To access the value of a variable in the command, use the double dollar sign prefix ($$) together with your variable name in the form $$<variable_name>. For example: $$targetTotal.

To use a variable to filter results, you must access the variable within the $expr operator.

For a complete example using let and variables, see Update with let Variables.

Behavior

Sharded Collections

If deleteMany() is run outside a transaction, operations that target more than one shard broadcast the operation to all shards in the cluster.
If deleteMany() is run inside a transaction, operations that target more than one shard only target the relevant shards.

Warning

Due to concurrent chunk migrations, deleteMany() might run without deleting all documents that match the specified filter. To ensure you delete all matching documents, perform one of the following operations:

Run the deleteMany() method iteratively until the corresponding find query with the same filter returns no documents.
Run deleteMany() within a transaction.
Schedule the balancing window so chunk migrations only occur at specific times, and run any deleteMany() operations outside of the specified window.

Delete a Single Document

To delete a single document, use db.collection.deleteOne() instead.

Alternatively, use a field that is a part of a unique index such as _id.

Transactions

db.collection.deleteMany() can be used inside distributed transactions.

Do not explicitly set the write concern for the operation if run in a transaction. To use write concern with transactions, see Transactions and Write Concern.

Important

In most cases, a distributed transaction incurs a greater performance cost over single document writes, and the availability of distributed transactions should not be a replacement for effective schema design. For many scenarios, the denormalized data model (embedded documents and arrays) will continue to be optimal for your data and use cases. That is, for many scenarios, modeling your data appropriately will minimize the need for distributed transactions.

For additional transactions usage considerations (such as runtime limit and oplog size limit), see also Production Considerations.

Primary Node Failure

db.collection.deleteMany() deletes documents one at a time. If the primary node fails during a db.collection.deleteMany() operation, documents that were not yet deleted from secondary nodes are not deleted from the collection.

Oplog Entries

If a db.collection.deleteMany() operation successfully deletes one or more documents, the operation adds an entry for each deleted document on the oplog (operations log). If the operation fails or does not find any documents to delete, the operation does not add an entry on the oplog.

Examples

The examples on this page use data from the sample_mflix sample dataset. For details on how to load this dataset into your self-managed MongoDB deployment, see Load the sample dataset. If you made any modifications to the sample databases, you may need to drop and recreate the databases to run the examples on this page.

Delete Multiple Documents

The following operation deletes all documents where year is earlier than 1910:

db.movies.deleteMany( { "year": { $lt: 1910 } } )

{ acknowledged: true, deletedCount: 4 }

Similarly, this operation deletes all documents where rated equals "G" and year is earlier than 1950:

db.movies.deleteMany( { "rated": "G", "year": { $lt: 1950 } } )

{ acknowledged: true, deletedCount: 9 }

deleteMany() with a Timeout and Query Variables

The following operation deletes all documents where year is earlier than the cutoffYear variable. The example also sets a time limit of 3 seconds:

db.movies.deleteMany(
    { $expr: { $lt: [ "$year", "$$cutoffYear" ] } },
    {
        let: { cutoffYear: 1910 },
        maxTimeMS: 3000
    }
)

{ acknowledged: true, deletedCount: 4 }

deleteMany() with Write Concern

Given a three member replica set, the following operation specifies a w of majority and wtimeout of 100:

db.movies.deleteMany(
    { "rated": "G", "year": { $lt: 1950 } },
    { writeConcern: { w: "majority", wtimeout: 100 } }
)

{ acknowledged: true, deletedCount: 9 }

If the acknowledgment takes longer than the wtimeout limit, MongoDB throws a write concern error.

Specify Collation

Collation allows users to specify language-specific rules for string comparison, such as rules for lettercase and accent marks.

The following operation uses the collation option with English locale and strength: 2. The filter rated: "g" matches documents with rated: "G" stored in the collection:

db.movies.deleteMany(
   { rated: "g", year: { $lt: 1950 } },
   { collation: { locale: "en", strength: 2 } }
)

{ acknowledged: true, deletedCount: 9 }

Specify `hint` for Delete Operations

Create indexes on the rated and metacritic fields:

db.movies.createIndex( { rated: 1 } )
db.movies.createIndex( { metacritic: 1 } )

The following delete operation explicitly hints to use the index { rated: 1 }:

db.movies.deleteMany(
   { "metacritic": { $lte: 15 }, "rated": "PG" },
   { hint: { rated: 1 } }
)

{ acknowledged: true, deletedCount: 7 }

Note

If you specify an index that does not exist, the operation errors.

To view the indexes used, you can use the $indexStats pipeline:

db.movies.aggregate( [ { $indexStats: { } }, { $sort: { name: 1 } } ] )

The accesses.ops field in the $indexStats output indicates the number of operations that used the index.

Back

db.collection.dataSize

db.collection.deleteOne

Definition

Note

Compatibility

Note

Syntax

Behavior

Sharded Collections

Warning

Delete a Single Document

Transactions

Important

Primary Node Failure

Oplog Entries

Examples

Delete Multiple Documents

deleteMany() with a Timeout and Query Variables

deleteMany() with Write Concern

Specify Collation

Specify hint for Delete Operations

Note

Specify `hint` for Delete Operations