[[["易于理解","easyToUnderstand","thumb-up"],["解决了我的问题","solvedMyProblem","thumb-up"],["其他","otherUp","thumb-up"]],[["很难理解","hardToUnderstand","thumb-down"],["信息或示例代码不正确","incorrectInformationOrSampleCode","thumb-down"],["没有我需要的信息/示例","missingTheInformationSamplesINeed","thumb-down"],["翻译问题","translationIssue","thumb-down"],["其他","otherDown","thumb-down"]],["最后更新时间 (UTC)：2025-09-04。"],[[["\u003cp\u003eTask queues enable applications to perform tasks asynchronously outside of a user request, with worker services executing these tasks later.\u003c/p\u003e\n"],["\u003cp\u003eThere are two types of task queues: push queues, which deliver HTTP requests to worker services, and pull queues, which require worker services to lease tasks.\u003c/p\u003e\n"],["\u003cp\u003ePush queues are suitable for managing slow operations and scheduling tasks, allowing control over the rate of task execution and scaling behavior.\u003c/p\u003e\n"],["\u003cp\u003ePull queues offer greater flexibility in task processing but necessitate more process management by the user, with leased tasks needing to be completed or deleted before a specified deadline.\u003c/p\u003e\n"],["\u003cp\u003eAll task queue tasks are performed asynchronously, with a built-in retry mechanism for tasks that fail during the initial attempt.\u003c/p\u003e\n"]]],[],null,["# Task Queue Overview\n\n\u003cbr /\u003e\n\n\u003cbr /\u003e\n\n\nGo Java PHP Python\n\nThis page describes what task queues are, and when and how to use them.\nTask queues let applications perform work, called *tasks* ,\nasynchronously outside of a user request. If an app needs to execute work\nin the background, it adds tasks to *task queues*. The tasks are executed later,\nby worker services.\n\nThe Task Queue service is designed for asynchronous work. It does not\nprovide strong guarantees around the timing of task delivery and is therefore\nunsuitable for interactive applications where a user is waiting for the result.\n| This API is supported for first-generation runtimes and can be used when [upgrading to corresponding second-generation runtimes](/appengine/docs/standard/\n|\n| /services/access). If you are updating to the App Engine runtime, refer to the [Upgrade to second-generation runtimes]() page to learn about your migration options for legacy bundled services.\n\nPush queues and pull queues\n---------------------------\n\nTask queues come in two flavors, *push* and *pull*. The manner in which the\nTask Queue service dispatches task requests to worker services is different for\nthe different queues.\n\n**Push queues** run tasks by delivering HTTP requests to App Engine worker services.\nThey dispatch these requests at a reliable, steady rate and guarantee\nreliable task execution. Because you can control the rate at which tasks are\nsent from the queue, you can control the workers' scaling behavior and hence\nyour costs.\n\nBecause tasks are executed as requests targeted at App Engine\nservices, they are subject to stringent deadlines. Tasks handled by automatic\nscaling services must finish in ten minutes. Tasks handled by basic and manual\nscaling services can run for up to 24 hours.\n\n**Pull queues** do not dispatch tasks at all. They depend on other worker\nservices to \"lease\" tasks from the queue on their own initiative. Pull queues\ngive you more power and flexibility over when and where tasks are processed, but\nthey also require you to do more process management. When a task is leased the\nleasing worker declares a deadline. By the time the deadline arrives the worker\nmust either complete the task and delete it or the Task Queue service will\nallow another worker to lease it.\n\n| **Tip:** In some cases [Google Cloud Pub/Sub](/pubsub/overview) is a good alternative to pull queues.\n\nAll task queue tasks are performed **asynchronously**. The application that creates\nthe task hands it off to the queue. The originating application is not notified\nwhether or not the task completes, or if it was successful.\n\nIf a worker fails to process a task, the Task Queue service provides the queue\nwith a retry mechanism, so the task can be retried a finite number of times.\n\nUse cases\n---------\n\n### Push queues\n\nOne typical push queue use case is a \"slow\" operation. Consider a social\nnetwork messaging system. Every time a user sends a message, the network needs\nto update the followers of the sender. This can be a very time-consuming\noperation. Using a push queue, the application can enqueue a task for each\nmessage as it arrives to be dispatched to a worker service for processing. When\nthe worker receives the task request, it can retrieve the sender's list of\nfollowers and update the DB for each one. The worker can be made even more\nefficient by enqueuing another pushtask for each database update.\n\nAnother use for push queues is scheduled tasks. Imagine an application that\nimplements an ad campaign. A group of tasks written to send out emails can be\nadded to a push queue with instructions to withhold the tasks until a specified\ntime in the future. When the due date arrives, the Task Queue service will\nbegin to issue requests to execute the tasks.\n\nWhat's next\n-----------\n\n- Read about [push queues](/appengine/docs/standard/services/taskqueue/push)"]]
