This topic provides answers to some frequently asked questions about nodes that are waiting for resources.

Why does a node wait for resources?

  • Problem description
    After the scheduling system commits a node to a compute engine, the node may wait for resources due to the following reasons:
    • The node waits for a resource group for scheduling.
    • If the node is a data synchronization node in Data Integration, the node waits for a resource group for Data Integration.
    • If the node is a computing node, the node waits for computing resources.
  • Cause

    The resources in a resource group are limited. If the resources are occupied by a node for an extended period of time, other nodes cannot be run until the occupied resources are released. For more information about how the scheduling system commits nodes, see Overview.

Why does a node wait for gateway resources for an extended period of time?

  • Problem description

    The log of a node shows that the node is waiting for gateway resources.

  • Cause

    The number of nodes that are running in parallel on the related resource group for scheduling reaches the upper limit.

  • Solution
    Wait until the nodes that are running release the occupied resources or scale out your exclusive resource group for scheduling. You can use one of the following methods to view resource usage in the resource group:
    • If you use the shared resource group for scheduling, you can view the resource usage in the resource group on the Overview page of Operation Center.
      Note The peak hours for DataWorks nodes are from 00:00 to 09:00 every day. During this period, resources in the shared resource group for scheduling may be insufficient, and nodes may wait for resources. You can change the scheduling time of the node or purchase an exclusive resource group for scheduling in the DataWorks console.
    • If you use an exclusive resource group for scheduling, you can log on to the DataWorks console, go to the Exclusive Resource Groups tab of the Resource Groups page or go to the Resource page of Operation Center, and then view the nodes that are running on the exclusive resource group for scheduling and the resource usage in the resource group.
      • View resource usage in the DataWorks console.
        Log on to the DataWorks console and click Resource Groups in the left-side navigation pane. On the Exclusive Resource Groups tab of the Resource Groups page, find the exclusive resource group and view the resource usage in the Resource Group Usage column. Then, you can click the percentage value in the Resource Group Usage column, and view the details of the resource group and the resource usage in the resource group. Resource Group Usage
      • View resource usage in Operation Center.
        Go to Operation Center, click Resource in the left-side navigation pane, and then view the information about resource groups, such as the resource usage. Resource
        On the Intelligent Diagnosis page, you can view the information about nodes that are running and waiting in a queue. You can also view the nodes that are occupying resources when the current node is waiting for resources. Resource usage and nodes that are occupying resources
        To view the nodes that are running when the current node is waiting for resources, perform the following steps: On the Overview page of Operation Center, click Instance waiting for resource. On the page that appears, find the current node, right-click the node in the directed acyclic graph (DAG), and then select Instance Diagnose. On the page that appears, click the Resources tab and view the nodes that are displayed in the Resource-consuming tasks section. Instance Diagnose
        Note The maximum number of nodes that can be run in parallel on an exclusive resource group for scheduling varies based on the specifications of the resource group. For more information, see Performance metrics and pricing of exclusive resource groups for scheduling.

Why does a data synchronization node wait for resources for an extended period of time?

  • Problem description

    The log of a data integration node shows that the node is waiting for resources.

  • Cause

    This issue occurs because the number of nodes that are running in parallel on the current resource group for Data Integration exceeds the upper limit for the resource group. As a result, the node keeps waiting for resources.

  • Solution
    • Check whether the value of the concurrent parameter that is specified when you configure the node is excessively large. If the value is too large, you must set the parameter based on the upper limit for the resource group for Data Integration and the number of nodes that are running in parallel.
    • You may set the concurrent parameter of the node to a value that exceeds the upper limit for the resource group for Data Integration. In this case, stop the node and change the value of the concurrent parameter before you run the node again.
      Go to Operation Center. The Overview page appears. On the Overview page, click the Data Integration tab and view the details of data synchronization nodes in the Synchronization task execution details section. Synchronization task execution detailsSynchronization task execution details
      Note
      • You must set the concurrent parameter for a node based on the maximum number of nodes that can be run in parallel on an exclusive resource group for Data Integration. In addition, you must also consider the number of nodes that you want to run in parallel and the sum of the values of the concurrent parameter for each node.
      • A data synchronization node occupies the resources of a resource group for Data Integration. If resources are occupied by the node for an extended period of time, other nodes to be run on the resource group cannot be run.
    • Wait until the nodes that are running release the occupied resources or scale out your exclusive resource group for Data Integration. You can use one of the following methods to view resource usage in the resource group:
      • View resource usage in the DataWorks console.
        Log on to the DataWorks console and click Resource Groups in the left-side navigation pane. On the Exclusive Resource Groups tab of the Resource Groups page, find the exclusive resource group and view the resource usage in the Resource Group Usage column. Then, you can click the percentage value in the Resource Group Usage column, and view the details of the resource group and the resource usage in the resource group. Resource Group Usage
      • View resource usage in Operation Center.
        Go to Operation Center. Click Resource in the left-side navigation pane and view the information about resource groups, such as the resource usage and the nodes that are running on the resource groups. Resource
        Note The maximum number of nodes that can be run in parallel on an exclusive resource group for Data Integration varies based on the specifications of the resource group. For more information, see Performance metrics and pricing of exclusive resource groups for Data Integration.