Bulk()¶

Ordered Operations有序操作¶

With an ordered operations list, MongoDB executes the write operations in the list serially. 使用有序操作列表，MongoDB连续执行列表中的写操作。If an error occurs during the processing of one of the write operations, MongoDB will return without processing any remaining write operations in the list.如果在处理其中一个写入操作期间发生错误，MongoDB将返回，而不处理列表中的任何剩余写入操作。

Use db.collection.initializeOrderedBulkOp() to create a builder for an ordered list of write commands.使用db.collection.initializeOrderedBulkOp()为写入命令的有序列表创建生成器。

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列表通常比执行无序列表慢，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¶

With an unordered operations list, MongoDB can execute in parallel, as well as in a nondeterministic order, the write operations in the list. 使用无序操作列表，MongoDB可以并行执行列表中的写操作，也可以以不确定的顺序执行。If an error occurs during the processing of one of the write operations, MongoDB will continue to process remaining write operations in the list.如果在处理其中一个写操作时出错，MongoDB将继续处理列表中的其余写操作。

Use db.collection.initializeUnorderedBulkOp() to create a builder for an unordered list of write commands.使用db.collection.initializeUnorderedBulkOp()为无序的写命令列表创建生成器。

When executing an unordered list of operations, MongoDB groups the operations. With an unordered bulk operation, the operations in the list may be reordered to increase performance. 在执行无序的操作列表时，MongoDB会对操作进行分组。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，请参阅事务和写关注点。