[[["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)：2025-08-17。"],[],[],null,["# Request Frequency\n=================\n\nUpdate requests\n---------------\n\nTo prevent server overload and to benefit from optimal protection, the Update\nAPI imposes time intervals for how often a client can send requests to the\nWeb Risk server to perform URL checks\n([`hashes.search`](/web-risk/docs/update-api#example-hashessearch))\nor to update the local database\n([`threatLists.computeDiff`](/web-risk/docs/update-api#example-threatlistsComputediff)).\n\nThe initial request for data must happen at a random interval between 0 and 1\nminutes after the client starts or wakes up. Subsequent requests can happen only\nafter the\n[minimum wait duration](/web-risk/docs/request-frequency#minimum_wait_duration)\nor\n[back-off mode](/web-risk/docs/request-frequency#back_off_mode)\ntime limit has been observed.\n\nMinimum wait duration\n---------------------\n\nBoth the\n[hashes.search response](/web-risk/docs/update-api#http_post_response_2)\nand\n[threatLists.computeDiff response](/web-risk/docs/update-api#http_post_response)\nhave a `minimumWaitDuration` field that clients must obey.\n\nIf the `minimumWaitDuration` field **is not set** in the\nresponse, clients can update as frequently as they want and send as many\n`threatListUpdates` or `fullHashes` requests as they want.\n\nIf the `minimumWaitDuration` field **is set** in the response,\nclients cannot update more frequently than the length of the wait duration. For\nexample, if a `fullHashes` response contains a minimum wait duration of 1 hour,\nthe client must not send send any `fullHashes` requests until that hour passes,\neven if the user is visiting a URL whose hash prefix matches the local database.\n(Note that clients can update less frequently than the minimum wait duration but\nthis may negatively affect protection.)\n\nBack-off mode\n-------------\n\nFor the recommended backoff procedure, read our\n[Service Level Agreement](/web-risk/sla)."]]
