Change a Document's Shard Key Value更改文档的分片键值

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Starting in MongoDB 4.2, you can update a document's shard key value unless the shard key field is the immutable _id field.从MongoDB 4.2开始，您可以更新文档的分片键值，除非分片键字段是不可变的_id字段。

Important重要
When updating the shard key value更新分片键值时
  • You must be on a mongos. 你一定在mongos上。Do not issue the operation directly on the shard.不要直接在分片上发出操作。
  • You must run either in a transaction or as a retryable write.您必须在事务中运行或作为可重试写入运行。
  • You must include an equality condition on the full shard key in the query filter. 您必须在查询筛选器中的完整分片键上包含相等条件。For example, consider a messages collection that uses { activityid: 1, userid : 1 } as the shard key. 例如，考虑使用{activityid:1, userid:1}作为分片键的messages集合。To update the shard key value for a document, you must include activityid: <value>, userid: <value> in the query filter. 要更新文档的分片键值，必须在查询筛选器中包括activityid: <value>, userid: <value>。You can include additional fields in the query as appropriate.您可以根据需要在查询中包含其他字段。

See also the specific write command/methods for additional operation-specific requirements when run against a sharded collection.另请参阅特定的写入命令/方法，以了解针对分片集合运行时的其他特定于操作的要求。

To update a shard key value, use the following operations:要更新分片键值，请使用以下操作：

Command命令Method方法
update with multi: false使用multi: false更新

db.collection.replaceOne()

db.collection.updateOne()

To set to a non-null value, the update must be performed either inside a transaction or as a retryable write.要设置为非null值，必须在事务内部或作为可重试写入执行更新。

findAndModify

db.collection.findOneAndReplace()

db.collection.findOneAndUpdate()

db.collection.findAndModify()

To set to a non-null value, the update must be performed either inside a transaction or as a retryable write.要设置为非null值，必须在事务内部或作为可重试写入执行更新。

db.collection.bulkWrite()

Bulk.find.updateOne()

If the shard key modification results in moving the document to another shard, you cannot specify more than one shard key modification in the bulk operation; the batch size has to be 1.如果修改分片键导致文档移动到另一个分片，则在批量操作中不能指定多个分片键修改；批次大小必须为1。

If the shard key modification does not result in moving the document to another shard, you can specify multiple shard key modification in the bulk operation.如果修改分片键不会导致将文档移动到另一个分片，则可以在批量操作中指定多个分片键修改。

To set to a non-null value, the operation must be performed either inside a transaction or as a retryable write.要设置为非null值，必须在事务内部或作为可重试写入执行该操作。

Warning警告

Starting in version 4.4, documents in sharded collections can be missing the shard key fields. 从版本4.4开始，分片集合中的文档可能会缺少分片键字段。Take precaution to avoid accidentally removing the shard key when changing a document's shard key value.采取预防措施，避免在更改文档的分片键值时意外删除分片键。

Example示例

Consider a sales collection which is sharded on the location field. 考虑在location字段上分片的sales集合。The collection contains a document with the _id12345 and the location "". 该集合包含一个_id为12345且location为""的文档。To update the field value for this document, you can run the following command:要更新此文档的字段值，可以运行以下命令：

db.sales.updateOne(
  { _id: 12345, location: "" },
  { $set: { location: "New York"} }
)
Tip提示
See also: 参阅：

Set Missing Shard Key Fields设置缺少的分片键字段

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