Limit Server Execution Time限一致性务器执行时间

Timeout Inheritance超时继承

When you specify a timeoutMS option, the driver applies the timeout according to the same inheritance behaviors as the other Node.js driver options. The following table describes how the timeout value is inherited at each level:当您指定timeoutMS选项时，驱动程序将根据与其他Node.js驱动程序选项相同的继承行为应用超时。下表描述了如何在每个级别继承超时值：

For more information on overrides and specific options, see the Overrides section.有关替代和特定选项的更多信息，请参阅替代部分。

Transactions事务

When you create a new ClientSession instance to implement a transaction, use the defaultTimeoutMS option. You can set defaultTimeoutMS to specify the timeoutMS values to use for:当您创建新的ClientSession实例来实现事务时，请使用defaultTimeoutMS选项。您可以设置defaultTimeoutMS来指定用于以下操作的timeoutMS值：

• commitTransaction()
• abortTransaction()
• withTransaction()
• endSession()

If you do not specify defaultTimeoutMS, the driver uses the timeoutMS value set on the parent MongoClient.如果不指定defaultTimeoutMS，驱动程序将使用在父MongoClient上设置的timeoutMS值。

You cannot override defaultTimeoutMS by setting the timeoutMS option on an operation in a transaction session provided by the withTransaction() callback. Doing so throws an error.您不能通过在withTransaction()回调提供的事务会话中的操作上设置timeoutMS选项来覆盖defaultTimeoutMS。这样做会引发错误。

Client Encryption客户端加密

When you use Client-Side Field Level Encryption (CSFLE), the driver uses the timeoutMS option to limit the time allowed for encryption and decryption operations.当您使用客户端字段级加密（CSFLE）时，驱动程序会使用timeoutMS选项来限制加密和解密操作所允许的时间。

If you specify the timeoutMS option when you construct a ClientEncryption instance, it controls the lifetime of all operations performed on that instance. 如果在构造ClientEncryption实例时指定timeoutMS选项，则它将控制在该实例上执行的所有操作的生存期。If you do not provide timeoutMS, the instance inherits the timeoutMS setting from the MongoClient used in the ClientEncryption constructor.如果不提供timeoutMS，则实例将继承ClientEncryption构造函数中使用的MongoClient的timeoutMS设置。

If you set timeoutMS on both the client and directly in ClientEncryption, the value provided to ClientEncryption takes precedence.如果在客户端和直接在ClientEncryption中设置timeoutMS，则提供给ClientEncryption的值优先。

Cursor Lifetime Mode游标生存期模式

The cursor lifetime mode uses timeoutMS to limit the entire lifetime of a cursor. In this mode, the initialization of the cursor and all subsequent calls to the cursor methods must complete within the limit specified by the timeoutMS option. All documents must be returned within this limit. 游标生存期模式使用timeoutMS来限制游标的整个生存期。在此模式下，游标的初始化和对游标方法的所有后续调用必须在timeoutMS选项指定的限制内完成。所有文件必须在此限制内归还。Otherwise, the cursor's lifetime expires and a timeout error occurs.否则，游标的生存期将到期，并发生超时错误。

When you close a cursor by calling the toArray() or close() method, the timeout resets for the killCursors command to ensure server-side resources are cleaned up.当您通过调用toArray()或close()方法关闭游标时，killCursors命令的超时会重置，以确保服务器端资源得到清理。

The following example shows how to set the timeoutMS option to ensure that the cursor is initialized and all documents are retrieved within 10 seconds:以下示例显示了如何设置timeoutMS选项，以确保游标初始化，并在10秒内检索到所有文档：

const docs = await collection.find({}, {timeoutMS: 10000}).toArray();

Cursor Iteration Mode游标迭代模式

The cursor iteration mode uses the timeoutMS option to limit each call to the next(), hasNext(), or tryNext() method. 游标迭代模式使用timeoutMS选项来限制对next()、hasNext()或tryNext()方法的每次调用。The timeout refreshes after each call completes. This is the default mode for all tailable cursors, such as the tailable cursors returned by the find() method on capped collections or change streams.每次调用完成后，超时时间都会刷新。这是所有可伸缩游标的默认模式，例如上限集合或更改流上find()方法返回的可伸缩游标。

The following code example iterates over documents in the mflix collection using a cursor with the timeoutMode set to iteration, and then fetches and logs the imdb_url for each movie document:以下代码示例使用timeoutMode设置为iteration（迭代）的游标迭代mflix集合中的文档，然后获取并记录每个电影文档的imdb_url：

for await (const movie of mflix.find({}, { timeoutMode: 'iteration' })) {
   const imdbResponse = await fetch(movie.imdb_url);
   console.log(await imdbResponse.text());
}