如果您需要批处理任务以提高执行效率，拉取队列是不错的选择。一种解决方案利用了将标记附加到拉取任务的功能。工作器可以租用一组具有相同标记的任务。典型的例子包括维护着多种不同游戏排行榜的应用，这些游戏不断有许多玩家和团队参与。每次有新的高分记录诞生时，应用都可以将包含分数和玩家的拉取任务加入队列，并将游戏 ID 用作任务标记。工作器会定期“唤醒”，租用一组具有相同游戏 ID 的任务并更新排行榜。您可以使用指定的标记值明确租用任务，或是让服务决定发送哪一组具有类似标记的任务。
[[["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 dispatch tasks via HTTP requests to App Engine worker services, and pull queues, which require worker services to lease tasks.\u003c/p\u003e\n"],["\u003cp\u003ePush queues are well-suited for slow operations and scheduled tasks, allowing control over worker scaling and costs, while pull queues are ideal for batching tasks with dynamic tagging for efficient execution.\u003c/p\u003e\n"],["\u003cp\u003eTask queue tasks are performed asynchronously, meaning the application that creates the task is not notified of its completion or success.\u003c/p\u003e\n"],["\u003cp\u003eThe Task Queue service provides a retry mechanism for failed tasks, allowing them to be retried a certain number of times.\u003c/p\u003e\n"]]],[],null,["# Task Queue Overview\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| python3\n|\n| /services/access). If you are updating to the App Engine Python 3 runtime, refer to the [migration guide](/appengine/migration-center/standard/migrate-to-second-gen/python-differences) 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\n### Pull queues\n\nPull queues work well when you need to batch tasks together for efficient\nexecution. One solution takes advantage of the ability to attach a *tag* to a\npull task. Workers can lease a group of tasks that have the same tag. A typical\nexample might be an app that maintains leaderboards for numerous different games, with\nmany players and groups constantly in play. Every time there is a new high\nscore, the app can enqueue a pull task with the score and the player, and use\nthe game ID as a task tag. A worker periodically \"wakes up\", leases a group of\ntasks with the same game ID, and updates the leaderboard. You can lease tasks\nexplicitly, using a specified tag value, or let the service decide which group\nof similarly tagged tasks to send.\n\nBatching with tags can be very powerful. Since tags can be dynamically\ngenerated while your app is running, a worker can handle new game IDs with no\nspecial effort.\n\n\nWhat's next\n-----------\n\n- Read about [push queues](/appengine/docs/legacy/standard/python/taskqueue/push)\n- Read about [pull queues](/appengine/docs/legacy/standard/python/taskqueue/pull)"]]
