[[["容易理解","easyToUnderstand","thumb-up"],["確實解決了我的問題","solvedMyProblem","thumb-up"],["其他","otherUp","thumb-up"]],[["難以理解","hardToUnderstand","thumb-down"],["資訊或程式碼範例有誤","incorrectInformationOrSampleCode","thumb-down"],["缺少我需要的資訊/範例","missingTheInformationSamplesINeed","thumb-down"],["翻譯問題","translationIssue","thumb-down"],["其他","otherDown","thumb-down"]],["上次更新時間：2025-09-04 (世界標準時間)。"],[[["\u003cp\u003eTask queues enable applications to perform tasks asynchronously outside of a user request, allowing for background processing by worker services.\u003c/p\u003e\n"],["\u003cp\u003eThe Task Queue service is designed for asynchronous work and does not provide timing guarantees, making it unsuitable for applications requiring immediate responses.\u003c/p\u003e\n"],["\u003cp\u003ePush queues dispatch tasks as HTTP requests to App Engine worker services at a steady, reliable rate, allowing control over worker scaling and costs.\u003c/p\u003e\n"],["\u003cp\u003ePush queues are ideal for slow operations, such as updating user followers in a social network, or for scheduled tasks, like sending out emails in an ad campaign.\u003c/p\u003e\n"],["\u003cp\u003eIf a worker fails to process a task, the Task Queue service provides a retry mechanism, allowing for a finite number of retries to complete the task.\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| php-gen2\n|\n| /services/access). If you are updating to the App Engine PHP 7/8 runtime, refer to the [migration guide](/appengine/migration-center/standard/migrate-to-second-gen/php-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** are not supported in PHP 5.\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/legacy/standard/php/taskqueue/push)"]]
