Bulk.execute()¶

Ordered Operations有序操作¶

When executing an ordered list of operations, MongoDB groups the operations by the operation type and contiguity; i.e. contiguous operations of the same type are grouped together. 在执行有序的操作列表时，MongoDB根据操作类型和连续性对操作进行分组；即，相同类型的连续操作被分组在一起。For example, if an ordered list has two insert operations followed by an update operation followed by another insert operation, MongoDB groups the operations into three separate groups: first group contains the two insert operations, second group contains the update operation, and the third group contains the last insert operation. 例如，如果一个有序列表有两个插入操作，然后是一个更新操作，然后是另一个插入操作，MongoDB会将这些操作分为三个单独的组：第一组包含两个插入操作，第二组包含更新操作，第三组包含最后一个插入操作。This behavior is subject to change in future versions.这种行为可能会在将来的版本中发生更改。

Each group of operations can have at most 1000 operations. 每组操作最多可以有1000个操作。If a group exceeds this limit, MongoDB will divide the group into smaller groups of 1000 or less. 如果一个组超过此限制，MongoDB将把该组分成1000个或更少的小组。For example, if the bulk operations list consists of 2000 insert operations, MongoDB creates 2 groups, each with 1000 operations.例如，如果批量操作列表包含2000个插入操作，MongoDB将创建2个组，每个组包含1000个操作。

The sizes and grouping mechanics are internal performance details and are subject to change in future versions.尺寸和分组机制是内部性能细节，在未来版本中可能会发生更改。

To see how the operations are grouped for a bulk operation execution, call Bulk.getOperations() after the execution.要查看批量操作执行时操作的分组方式，请在执行后调用Bulk.getOperations()。

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.在分片集合上执行操作的有序无序列表慢，因为对于有序>列表，每个操作都必须等待前一个操作完成。

Unordered Operations无序操作¶

When executing an unordered list of operations, MongoDB groups the operations. 在执行无序的操作列表时，MongoDB会对操作进行分组。With an unordered bulk operation, the operations in the list may be reordered to increase performance. 对于无序批量操作，可以对列表中的操作重新排序以提高性能。As such, applications should not depend on the ordering when performing unordered bulk operations.因此，应用程序在执行无序批量操作时不应依赖于排序。

Each group of operations can have at most 1000 operations. 每组操作最多可以有1000个操作。If a group exceeds this limit, MongoDB will divide the group into smaller groups of 1000 or less. 如果一个组超过此限制，MongoDB将把该组分成1000个或更少的小组。For example, if the bulk operations list consists of 2000 insert operations, MongoDB creates 2 groups, each with 1000 operations.例如，如果批量操作列表包含2000个插入操作，MongoDB将创建2个组，每个组包含1000个操作。

The sizes and grouping mechanics are internal performance details and are subject to change in future versions.尺寸和分组机制是内部性能细节，在未来版本中可能会发生更改。

To see how the operations are grouped for a bulk operation execution, call Bulk.getOperations() after the execution.要查看批量操作执行时操作的分组方式，请在执行后调用Bulk.getOperations()。

Transactions事务¶

Bulk() can be used inside multi-document transactions.可以在多文档事务中使用。

For Bulk.find.insert() operations, the collection must already exist.对于Bulk.find.insert()操作，集合必须已经存在。

For Bulk.find.upsert(), if the operation results in an upsert, the collection must already exist.对于Bulk.find.upsert()，如果操作导致upsert，则集合必须已经存在。

Do not explicitly set the write concern for the operation if run in a transaction. 如果在事务中运行，请不要显式设置操作的写入关注点。To use write concern with transactions, see Transactions and Write Concern.要将写关注点用于事务，请参阅事务和写入关注。

Execute Bulk Operations执行批量操作¶

The following initializes a Bulk() operations builder on the items collection, adds a series of insert operations, and executes the operations:以下内容初始化items集合上的Bulk()操作生成器，添加一系列插入操作，并执行这些操作：

var bulk = db.items.initializeUnorderedBulkOp();
bulk.insert( { item: "abc123", status: "A", defaultQty: 500, points: 5 } );
bulk.insert( { item: "ijk123", status: "A", defaultQty: 100, points: 10 } );
bulk.execute( );

The operation returns the following BulkWriteResult() object:该操作返回以下BulkWriteResult()对象：

BulkWriteResult({
   "writeErrors" : [ ],
   "writeConcernErrors" : [ ],
   "nInserted" : 2,
   "nUpserted" : 0,
   "nMatched" : 0,
   "nModified" : 0,
   "nRemoved" : 0,
   "upserted" : [ ]
})

For details on the return object, see BulkWriteResult(). 有关返回对象的详细信息，请参阅BulkWriteResult()。For details on the batches executed, see Bulk.getOperations().有关执行的批处理的详细信息，请参阅Bulk.getOperations()。

Override Default Write Concern覆盖默认写关注点¶

The following operation to a replica set specifies a write concern of "w: majority" with a wtimeout of 5000 milliseconds such that the method returns after the writes propagate to a majority of the voting replica set members or the method times out after 5 seconds.以下对副本集的操作指定了一个写关注点"w: majority"，wtimeout为5000毫秒，这样该方法在写操作传播到大多数投票副本集成员后返回，或者该方法在5秒后超时。

var bulk = db.items.initializeUnorderedBulkOp();
bulk.insert( { item: "efg123", status: "A", defaultQty: 100, points: 0 } );
bulk.insert( { item: "xyz123", status: "A", defaultQty: 100, points: 0 } );
bulk.execute( { w: "majority", wtimeout: 5000 } );

The operation returns the following BulkWriteResult() object:该操作返回以下BulkWriteResult()对象：

BulkWriteResult({
   "writeErrors" : [ ],
   "writeConcernErrors" : [ ],
   "nInserted" : 2,
   "nUpserted" : 0,
   "nMatched" : 0,
   "nModified" : 0,
   "nRemoved" : 0,
   "upserted" : [ ]
})