[[["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\u003eCloud Data Fusion employs a flow control mechanism to prevent an excess of start requests, which could lead to pipeline issues.\u003c/p\u003e\n"],["\u003cp\u003eThe flow control mechanism uses a launch threshold that limits the number of launch requests not yet in the "Running" state and a runs threshold that limits the number of outstanding requests not yet finished.\u003c/p\u003e\n"],["\u003cp\u003eWhen either the launch or runs threshold is exceeded, new start requests will be rejected, and the rejection will be noted in the logs and displayed in the UI.\u003c/p\u003e\n"],["\u003cp\u003eMetrics are available to monitor the number of launching requests (\u003ccode\u003eflowcontrol.launching.count\u003c/code\u003e), running pipelines and jobs (\u003ccode\u003eflowcontrol.running.count\u003c/code\u003e), and rejected runs (\u003ccode\u003eprogram.rejected.runs\u003c/code\u003e).\u003c/p\u003e\n"]]],[],null,["# Cloud Data Fusion flow control overview\n\nA flow control mechanism in Cloud Data Fusion prevents you from submitting\ntoo many requests, which can cause stuck or failed pipeline runs. This mechanism\napplies to start (`Launch`) requests for the following pipelines and jobs in all\neditions of Cloud Data Fusion, versions 6.6 and later:\n\n- Batch pipelines\n- Real-time pipelines\n- Replication jobs\n\nThresholds\n----------\n\nTo control the number of outstanding start requests in Cloud Data Fusion,\nflow control relies on two thresholds:\n\nLaunch threshold\n: Limits the number of launch requests being made. If the\n number of launch requests received by Cloud Data Fusion that are not yet in\n `Running` state is greater than the launch threshold (number of launch requests\n that aren't running yet \\\u003e launch threshold), the request is rejected. The\n number includes batch pipelines, real-time pipelines, and\n replication jobs.\n\nRuns threshold\n: Limits the number of outstanding launch requests in\n the system. If the number of outstanding launch requests received by\n Cloud Data Fusion that have not yet finished is greater than a specified\n runs threshold (number of outstanding requests that aren't finished yet \\\u003e runs\n threshold), the request is rejected.\n\nRejected requests\n-----------------\n\nIf either threshold is met, every new start request gets rejected. For example,\na rejected batch pipeline has a `Rejected` status in the logs, and a dialog in\nthe UI describes why the launch was rejected.\n\nMetrics\n-------\n\nThe number of launching and running pipelines along with the number of rejected\npipelines in the system can be accessed through the metrics service as follows.\n\n### `Launching` metric\n\nReports the number of launching requests in the system. That is, it reports the\nnumber of launch requests that are in `Provisioning` or `Starting` states.\n\nMetrics name: `flowcontrol.launching.count` \n\n POST /v3/metrics/query?metric=system.flowcontrol.launching.count\n\n### `Running` metric\n\nReports the number of running pipelines and jobs in the system. The run\nthreshold is based on the sum of the `Launching` and `Running` metrics values.\n\nMetrics name: `flowcontrol.running.count` \n\n POST /v3/metrics/query?metric=system.flowcontrol.running.count\n\n### `Rejected` metric\n\nReports the number of rejected runs due to the flow control mechanism.\n\nMetrics name: `program.rejected.runs` \n\n POST /v3/metrics/query?metric=system.program.rejected.runs\n\nWhat's next\n-----------\n\n- For examples of providing tags and aggregating the `Rejected` metric for different pipelines, see [CDAP Metrics Microservices](https://cdap.atlassian.net/wiki/spaces/DOCS/pages/477692194/Metrics+Microservices#Querying-a-Metric)."]]
