定义
cursor.noCursorTimeout()重要
mongosh 方法
This page documents a
mongoshmethod. This is not the documentation for a language-specific driver, such as Node.js.如需了解 MongoDB API 驱动程序，请参阅特定语言的 MongoDB 驱动程序文档。
指示服务器避免在一段时间不活动后自动关闭游标。
The
noCursorTimeout()method has the following prototype form:db.collection.find(<query>).noCursorTimeout()
兼容性
此方法可用于以下环境中托管的部署：
- MongoDB Atlas: The fully managed service for MongoDB deployments in the cloud
重要
This command is not supported in M0 and Flex clusters. For more information, see Unsupported Commands.
MongoDB Enterprise：基于订阅、自我管理的 MongoDB 版本
MongoDB Community：源代码可用、免费使用且可自行管理的 MongoDB 版本
行为
会话空闲超时重写 noCursorTimeout
MongoDB drivers and mongosh associate all operations with a server session, with the exception of unacknowledged write operations. For operations not explicitly associated with a session (i.e. using Mongo.startSession()), MongoDB drivers and mongosh create an implicit session and associate it with the operation.
If a session is idle for longer than 30 minutes, the MongoDB server marks that session as expired and may close it at any time. When the MongoDB server closes the session, it also kills any in-progress operations and open cursors associated with the session. This includes cursors configured with noCursorTimeout() or a maxTimeMS() greater than 30 minutes.
Consider an application that issues a db.collection.find() with cursor.noCursorTimeout(). The server returns a cursor along with a batch of documents defined by the cursor.batchSize() of the find(). The session refreshes each time the application requests a new batch of documents from the server. However, if the application takes longer than 30 minutes to process the current batch of documents, the session is marked as expired and closed. When the server closes the session, it also kills the cursor despite the cursor being configured with noCursorTimeout(). When the application requests the next batch of documents, the server returns an error.
刷新游标 refreshSessions
对于返回游标的操作，如果游标的空闲时间可能超过 30 分钟，则使用 Mongo.startSession() 在显式会话中发出操作，并使用 refreshSessions 命令定期刷新会话。例如：
var session = db.getMongo().startSession() var sessionId = session sessionId // show the sessionId var cursor = session.getDatabase("examples").getCollection("data").find().noCursorTimeout() var refreshTimestamp = new Date() // take note of time at operation start while (cursor.hasNext()) { // Check if more than 5 minutes have passed since the last refresh if ( (new Date()-refreshTimestamp)/1000 > 300 ) { print("refreshing session") db.adminCommand({"refreshSessions" : [sessionId]}) refreshTimestamp = new Date() } // process cursor normally }
In the example operation, the db.collection.find() method is associated with an explicit session. The cursor is configured with cursor.noCursorTimeout() to prevent the server from closing the cursor if idle. The while loop includes a block that uses refreshSessions to refresh the session every 5 minutes. Since the session will never exceed the 30 minute idle timeout, the cursor can remain open indefinitely.
For MongoDB drivers, defer to the driver documentation for instructions and syntax for creating sessions.