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db.collection.bulkWrite()

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  • Definition
  • Behavior
  • Examples

Definition

db.collection.bulkWrite()

Important

mongosh Method

This page documents a mongosh method. This is not the documentation for a language-specific driver, such as Node.js.

For MongoDB API drivers, refer to the language-specific MongoDB driver documentation.

Performs multiple write operations with controls for order of execution.

db.collection.bulkWrite() has the following syntax:

db.collection.bulkWrite(
   [ <operation 1>, <operation 2>, ... ],
   {
      writeConcern : <document>,
      ordered : <boolean>
   }
)
Parameter
Type
Description
operations
array

An array of bulkWrite() write operations.

Valid operations are:

See Write Operations for usage of each operation.

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.

ordered
boolean

Optional. A boolean specifying whether the mongod instance should perform an ordered or unordered operation execution. Defaults to true.

See Execution of Operations

Returns:
  • A boolean acknowledged as true if the operation ran with write concern or false if write concern was disabled.
  • A count for each write operation.
  • An array containing an _id for each successfully inserted or upserted documents.

Behavior

bulkWrite() takes an array of write operations and executes each of them. By default operations are executed in order. See Execution of Operations for controlling the order of write operation execution.

Write Operations

insertOne

Inserts a single document into the collection.

db.collection.bulkWrite( [
   { insertOne : { "document" : <document> } }
] )

See db.collection.insertOne().

updateOne and updateMany

updateOne updates a single document in the collection that matches the filter. If multiple documents match, updateOne will update the first matching document only.

db.collection.bulkWrite( [
   { updateOne :
      {
         "filter": <document>,
         "update": <document or pipeline>,            // Changed in 4.2
         "upsert": <boolean>,
         "collation": <document>,                     // Available starting in 3.4
         "arrayFilters": [ <filterdocument1>, ... ],  // Available starting in 3.6
         "hint": <document|string>                    // Available starting in 4.2.1
      }
   }
] )

updateMany updates all documents in the collection that match the filter.

db.collection.bulkWrite( [
   { updateMany :
      {
         "filter" : <document>,
         "update" : <document or pipeline>,          // Changed in MongoDB 4.2
         "upsert" : <boolean>,
         "collation": <document>,                    // Available starting in 3.4
         "arrayFilters": [ <filterdocument1>, ... ], // Available starting in 3.6
         "hint": <document|string>                   // Available starting in 4.2.1
      }
   }
] )
Field
Notes
filter
The selection criteria for the update. The same query selectors as in the db.collection.find() method are available.
update

The update operation to perform. Can specify either:

upsert

Optional. A boolean to indicate whether to perform an upsert.

By default, upsert is false.

arrayFilters
Optional. An array of filter documents that determine which array elements to modify for an update operation on an array field.
collation
Optional. Specifies the collation to use for the operation.
hint

Optional. The index to use to support the update filter. If you specify an index that does not exist, the operation errors.

New in version 4.2.1.

For details, see db.collection.updateOne() and db.collection.updateMany().

replaceOne

replaceOne replaces a single document in the collection that matches the filter. If multiple documents match, replaceOne will replace the first matching document only.

db.collection.bulkWrite([
   { replaceOne :
      {
         "filter" : <document>,
         "replacement" : <document>,
         "upsert" : <boolean>,
         "collation": <document>,                    // Available starting in 3.4
         "hint": <document|string>                   // Available starting in 4.2.1
      }
   }
] )
Field
Notes
filter
The selection criteria for the replacement operation. The same query selectors as in the db.collection.find() method are available.
replacement
The replacement document. The document cannot contain update operators.
upsert
Optional. A boolean to indicate whether to perform an upsert. By default, upsert is false.
collation
Optional. Specifies the collation to use for the operation.
hint

Optional. The index to use to support the update filter. If you specify an index that does not exist, the operation errors.

New in version 4.2.1.

For details, see to db.collection.replaceOne().

deleteOne and deleteMany

deleteOne deletes a single document in the collection that match the filter. If multiple documents match, deleteOne will delete the first matching document only.

db.collection.bulkWrite([
   { deleteOne : {
      "filter" : <document>,
      "collation" : <document>                   // Available starting in 3.4
   } }
] )

deleteMany deletes all documents in the collection that match the filter.

db.collection.bulkWrite([
   { deleteMany: {
      "filter" : <document>,
      "collation" : <document>                    // Available starting in 3.4
   } }
] )
Field
Notes
filter
The selection criteria for the delete operation. The same query selectors as in the db.collection.find() method are available.
collation
Optional. Specifies the collation to use for the operation.

For details, see db.collection.deleteOne() and db.collection.deleteMany().

_id Field

If the document does not specify an _id field, then mongod adds the _id field and assign a unique ObjectId() for the document before inserting or upserting it. Most drivers create an ObjectId and insert the _id field, but the mongod will create and populate the _id if the driver or application does not.

If the document contains an _id field, the _id value must be unique within the collection to avoid duplicate key error.

Update or replace operations cannot specify an _id value that differs from the original document.

Execution of Operations

The ordered parameter specifies whether bulkWrite() will execute operations in order or not. By default, operations are executed in order.

The following code represents a bulkWrite() with five operations.

db.collection.bulkWrite(
   [
      { insertOne : <document> },
      { updateOne : <document> },
      { updateMany : <document> },
      { replaceOne : <document> },
      { deleteOne : <document> },
      { deleteMany : <document> }
   ]
)

In the default ordered : true state, each operation will be executed in order, from the first operation insertOne to the last operation deleteMany.

If ordered is set to false, operations may be reordered by mongod to increase performance. Applications should not depend on order of operation execution.

The following code represents an unordered bulkWrite() with six operations:

db.collection.bulkWrite(
   [
      { insertOne : <document> },
      { updateOne : <document> },
      { updateMany : <document> },
      { replaceOne : <document> },
      { deleteOne : <document> },
      { deleteMany : <document> }
   ],
   { ordered : false }
)

With ordered : false, the results of the operation may vary. For example, the deleteOne or deleteMany may remove more or fewer documents depending on whether the run before or after the insertOne, updateOne, updateMany, or replaceOne operations.

The number of operations in each group cannot exceed the value of the maxWriteBatchSize of the database. As of MongoDB 3.6, this value is 100,000. This value is shown in the hello.maxWriteBatchSize field.

This limit prevents issues with oversized error messages. If a group exceeds this limit, the client driver divides the group into smaller groups with counts less than or equal to the value of the limit. For example, with the maxWriteBatchSize value of 100,000, if the queue consists of 200,000 operations, the driver creates 2 groups, each with 100,000 operations.

Note

The driver only divides the group into smaller groups when using the high-level API. If using db.runCommand() directly (for example, when writing a driver), MongoDB throws an error when attempting to execute a write batch which exceeds the limit.

Starting in MongoDB 3.6, once the error report for a single batch grows too large, MongoDB truncates all remaining error messages to the empty string. Currently, begins once there are at least 2 error messages with total size greater than 1MB.

The sizes and grouping mechanics are internal performance details and are subject to change in future versions.

Executing an ordered list of operations on a sharded collection will generally be slower than executing an unordered list since with an ordered list, each operation must wait for the previous operation to finish.

Capped Collections

bulkWrite() write operations have restrictions when used on a capped collection.

updateOne and updateMany throw a WriteError if the update criteria increases the size of the document being modified.

replaceOne throws a WriteError if the replacement document has a larger size than the original document.

deleteOne and deleteMany throw a WriteError if used on a capped collection.

Time Series Collections

bulkWrite() write operations have restrictions when used on a time series collection. Only insertOne can be used on time series collections. All other operations will return a WriteError.

Error Handling

db.collection.bulkWrite() throws a BulkWriteError exception on errors (unless the operation is part of a transaction on MongoDB 4.0). See Error Handling inside Transactions.

Excluding write concern errors, ordered operations stop after an error, while unordered operations continue to process any remaining write operations in the queue, unless when run inside a transaction. See Error Handling inside Transactions.

Write concern errors are displayed in the writeConcernErrors field, while all other errors are displayed in the writeErrors field. If an error is encountered, the number of successful write operations are displayed instead of the inserted _id values. Ordered operations display the single error encountered while unordered operations display each error in an array.

Transactions

db.collection.bulkWrite() can be used inside multi-document transactions.

Important

In most cases, multi-document transaction incurs a greater performance cost over single document writes, and the availability of multi-document 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 multi-document transactions.

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

Inserts and Upserts within Transactions

For feature compatibility version (fcv) "4.4" and greater, if an insert operation or update operation with upsert: true is run in a transaction against a non-existing collection, the collection is implicitly created.

Note

You cannot create new collections in cross-shard write transactions. For example, if you write to an existing collection in one shard and implicitly create a collection in a different shard, MongoDB cannot perform both operations in the same transaction.

For fcv "4.2" or less, the collection must already exist for insert and upsert: true operations.

Write Concerns and 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.

Error Handling inside Transactions

Starting in MongoDB 4.2, if a db.collection.bulkWrite() operation encounters an error inside a transaction, the method throws a BulkWriteException (same as outside a transaction).

In 4.0, if the bulkWrite operation encounters an error inside a transaction, the error thrown is not wrapped as a BulkWriteException.

Inside a transaction, the first error in a bulk write causes the entire bulk write to fail and aborts the transaction, even if the bulk write is unordered.

Examples

Ordered Bulk Write Example

It is important that you understand bulkWrite() operation ordering and error handling. By default, bulkWrite() runs an ordered list of operations:

  • Operations run serially.

  • If an operation has an error, that operation and any following operations are not run.

  • Operations listed before the error operation are completed.

The bulkWrite() examples use the pizzas collection:

db.pizzas.insertMany( [
   { _id: 0, type: "pepperoni", size: "small", price: 4 },
   { _id: 1, type: "cheese", size: "medium", price: 7 },
   { _id: 2, type: "vegan", size: "large", price: 8 }
] )

The following bulkWrite() example runs these operations on the pizzas collection:

  • Adds two documents using insertOne.

  • Updates a document using updateOne.

  • Deletes a document using deleteOne.

  • Replaces a document using replaceOne.

try {
   db.pizzas.bulkWrite( [
      { insertOne: { document: { _id: 3, type: "beef", size: "medium", price: 6 } } },
      { insertOne: { document: { _id: 4, type: "sausage", size: "large", price: 10 } } },
      { updateOne: {
         filter: { type: "cheese" },
         update: { $set: { price: 8 } }
      } },
      { deleteOne: { filter: { type: "pepperoni"} } },
      { replaceOne: {
         filter: { type: "vegan" },
         replacement: { type: "tofu", size: "small", price: 4 }
      } }
   ] )
} catch( error ) {
   print( error )
}

Example output, which includes a summary of the completed operations:

{
   acknowledged: true,
   insertedCount: 2,
   insertedIds: { '0': 3, '1': 4 },
   matchedCount: 2,
   modifiedCount: 2,
   deletedCount: 1,
   upsertedCount: 0,
   upsertedIds: {}
}

If the collection already contained a document with an _id of 4 before running the previous bulkWrite() example, the following duplicate key exception is returned for the second insertOne operation:

writeErrors: [
   WriteError {
      err: {
         index: 1,
         code: 11000,
         errmsg: 'E11000 duplicate key error collection: test.pizzas index: _id_ dup key: { _id: 4 }',
         op: { _id: 4, type: 'sausage', size: 'large', price: 10 }
      }
   }
],
result: BulkWriteResult {
   result: {
      ok: 1,
      writeErrors: [
         WriteError {
            err: {
               index: 1,
               code: 11000,
               errmsg: 'E11000 duplicate key error collection: test.pizzas index: _id_ dup key: { _id: 4 }',
               op: { _id: 4, type: 'sausage', size: 'large', price: 10 }
            }
         }
      ],
      writeConcernErrors: [],
      insertedIds: [ { index: 0, _id: 3 }, { index: 1, _id: 4 } ],
      nInserted: 1,
      nUpserted: 0,
      nMatched: 0,
      nModified: 0,
      nRemoved: 0,
      upserted: []
   }
}

Because the bulkWrite() example is ordered, only the first insertOne operation is completed.

To complete all operations that do not have errors, run bulkWrite() with ordered set to false. For an example, see the following section.

Unordered Bulk Write Example

To specify an unordered bulkWrite(), set ordered to false.

In an unordered bulkWrite() list of operations:

  • Operations can run in parallel (not guaranteed). For details. See Ordered vs Unordered Operations.

  • Operations with errors are not completed.

  • All operations without errors are completed.

Continuing the pizzas collection example, drop and recreate the collection:

db.pizzas.insertMany( [
   { _id: 0, type: "pepperoni", size: "small", price: 4 },
   { _id: 1, type: "cheese", size: "medium", price: 7 },
   { _id: 2, type: "vegan", size: "large", price: 8 }
] )

In the following example:

  • bulkWrite() runs unordered operations on the pizzas collection.

  • The second insertOne operation has the same _id as the first insertOne, which causes a duplicate key error.

try {
   db.pizzas.bulkWrite( [
      { insertOne: { document: { _id: 3, type: "beef", size: "medium", price: 6 } } },
      { insertOne: { document: { _id: 3, type: "sausage", size: "large", price: 10 } } },
      { updateOne: {
         filter: { type: "cheese" },
         update: { $set: { price: 8 } }
      } },
      { deleteOne: { filter: { type: "pepperoni"} } },
      { replaceOne: {
         filter: { type: "vegan" },
         replacement: { type: "tofu", size: "small", price: 4 }
      } }
   ],
   { ordered: false } )
} catch( error ) {
   print( error )
}

Example output, which includes the duplicate key error and a summary of the completed operations:

writeErrors: [
   WriteError {
      err: {
         index: 1,
         code: 11000,
         errmsg: 'E11000 duplicate key error collection: test.pizzas index: _id_ dup key: { _id: 3 }',
         op: { _id: 3, type: 'sausage', size: 'large', price: 10 }
      }
   }
],
result: BulkWriteResult {
   result: {
      ok: 1,
      writeErrors: [
         WriteError {
            err: {
               index: 1,
               code: 11000,
               errmsg: 'E11000 duplicate key error collection: test.pizzas index: _id_ dup key: { _id: 3 }',
               op: { _id: 3, type: 'sausage', size: 'large', price: 10 }
            }
         }
      ],
      writeConcernErrors: [],
      insertedIds: [ { index: 0, _id: 3 }, { index: 1, _id: 3 } ],
      nInserted: 1,
      nUpserted: 0,
      nMatched: 2,
      nModified: 2,
      nRemoved: 1,
      upserted: []
   }
}

The second insertOne operation fails because of the duplicate key error. In an unordered bulkWrite(), any operation without an error is completed.

Bulk Write with Write Concern Example

Continuing the pizzas collection example, drop and recreate the collection:

db.pizzas.insertMany( [
   { _id: 0, type: "pepperoni", size: "small", price: 4 },
   { _id: 1, type: "cheese", size: "medium", price: 7 },
   { _id: 2, type: "vegan", size: "large", price: 8 }
] )

The following bulkWrite() example runs operations on the pizzas collection and sets a "majority" write concern with a 100 millisecond timeout:

try {
   db.pizzas.bulkWrite( [
      { updateMany: {
         filter: { size: "medium" },
         update: { $inc: { price: 0.1 } }
      } },
      { updateMany: {
         filter: { size: "small" },
         update: { $inc: { price: -0.25 } }
      } },
      { deleteMany: { filter: { size: "large" } } },
      { insertOne: {
         document: { _id: 4, type: "sausage", size: "small", price: 12 }
      } } ],
      { writeConcern: { w: "majority", wtimeout: 100 } }
   )
} catch( error ) {
   print( error )
}

If the time for the majority of replica set members to acknowledge the operations exceeds wtimeout, the example returns a write concern error and a summary of completed operations:

result: BulkWriteResult {
   result: {
      ok: 1,
      writeErrors: [],
      writeConcernErrors: [
         WriteConcernError {
            err: {
               code: 64,
               codeName: 'WriteConcernFailed',
               errmsg: 'waiting for replication timed out',
               errInfo: { wtimeout: true, writeConcern: [Object] }
            }
         }
      ],
      insertedIds: [ { index: 3, _id: 4 } ],
      nInserted: 0,
      nUpserted: 0,
      nMatched: 2,
      nModified: 2,
      nRemoved: 0,
      upserted: [],
      opTime: { ts: Timestamp({ t: 1660329086, i: 2 }), t: Long("1") }
   }
}

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