Adding or Deleting DWS Logical Clusters/Virtual Warehouses

Prerequisites

• For a storage-compute coupled cluster, Logical Cluster must be toggled on so that the Logical Cluster tab is displayed in the navigation pane on the cluster details page. The Logical Cluster toggle switch only controls whether to display the Logical Cluster tab. When it is toggled on, the cluster will not be converted to a logical cluster.
• If there are no idle nodes, no logical cluster or compute group can be added. To add idle nodes, click Add Idle Node. For details, see Adding Nodes.

Precautions

• After a storage-compute coupled physical cluster is converted to a logical cluster, if the logical cluster list is empty, you need to add the first logical cluster. In this case, all physical nodes are allocated to the logical cluster.
• If the logical cluster list is not empty, the number of DNs and that of idle nodes in the current cluster are displayed in the Data Node (DN) area. If there are idle nodes, you can use them to create a logical cluster or compute group.
• When a physical cluster is converted to a logical cluster, the original resource pool configuration is cleared. The resource pool information configured after the cluster is converted to a logical cluster will be bound to the logical cluster.
• During conversion of a physical cluster to a logical cluster, if the physical cluster has data, the cluster will be locked. Complex DDL statements, such as operations on database objects, will block services. You are advised to perform the conversion during off-peak hours.
• A physical cluster cannot be rolled back to a physical cluster after it is converted to a logical cluster.

Procedure

1. Log in to the DWS console.
2. In the navigation pane on the left, choose Cluster > Cluster List.
3. In the cluster list, click the name of the target cluster to go to the Cluster Information page.
4. On the top navigation bar, click the Logical Clusters or Virtual Warehouses tab.
   Figure 1 Logical Cluster switch button
   

5. Click Add Logical Cluster or Add Compute Group. If the cluster meets inspection conditions, the Inspection page is displayed. Click Start Inspection and click OK in the displayed dialog box to perform an inspection. (To stop an inspection task, click Terminate Task.) When an inspection is ongoing, the inspection progress is displayed. Ensure that the inspection is passed and click Next to perform subsequent operations. For details, see Viewing Inspection Results.
   • If you access the Logical Clusters page for the first time, the metadata of the logical clusters created at the backend is synchronized to the frontend. After the synchronization is complete, you can view information about the logical clusters at the frontend. The logical cluster name is case sensitive. For example, metadata of lc1 and LC1 cannot be synchronized.
   • If the current storage-compute coupled cluster has service data, you can only convert the cluster into a logical cluster. In the displayed dialog box, enter the name of target logical cluster. The default name is lc_default. Click OK to convert the cluster to a logical cluster. Then, you can add nodes to the cluster and add more logical clusters.
   • You are advised to allocate tables in a database to the same logical cluster.

6. On the displayed page for adding a logical cluster/virtual warehouse, set the parameters by referring to the following table.

   Table 1 Parameters for adding a logical cluster

   Parameter	Description
   DNs to Add	For an ECS cluster, the number of idle nodes in the cluster is used by default. For details about how to add idle nodes, see Adding Nodes. For a BMS cluster, you can manually set the number of nodes to be added. It must be less than or equal to the number of idle nodes in the cluster.
   Scale to logical cluster/virtual warehouse	Enter the name of the new logical cluster/virtual warehouse. If you want to add nodes to an existing logical cluster or virtual warehouse, click Scale to Existing Logical Cluster or Scale Out to Existing Virtual Warehouse. The scale-out page is automatically displayed.
   Scale Online	If you enable this function, you can perform service operations during the scale-out.
   Terminate Job	This parameter can be set when Online Scale-out is enabled. If there is congestion during online scale-out, the system will wait for the specified duration before terminating the congested jobs. The value is an integer ranging from 30 to 1,200, in seconds.
   Time Before Blocked Job Termination (s)	This parameter is displayed when Terminate Job is enabled. This parameter takes effect when Terminate Job is enabled. After the wait time, the jobs blocking the scale-out will be terminated. Enter an integer ranging from 30 to 1,200.

7. Confirm that all information is correct, select I acknowledge the potential risks and agree to proceed with the change, and click Submit. The logical cluster will be added in a while.

Precautions

• The first manually added logical cluster/virtual warehouse cannot be deleted.
• After a logical cluster/virtual warehouse is deleted, nodes will be removed from the cluster. This operation is irreversible.
• When a logical cluster is deleted, only tables, foreign tables, and resource pools are deleted. The objects that depend on the tables (including the sequences, functions, and triggers that partially depend on the tables) in the logical cluster will also be deleted.
• During the deletion of a logical cluster, user association will be canceled, and the existing parent-child tenant relationships will be deleted.

Procedure

1. Log in to the DWS console.
2. In the navigation pane on the left, choose Cluster > Cluster List.
3. In the cluster list, click the name of the target cluster to go to the Cluster Information page.
4. In the navigation pane, choose Logical Clusters or Compute Groups. Locate the row that contains the logical cluster or compute group you want to delete, click More in the Operation column, and select Delete.
   • If a one-off deletion plan is associated with a read-only virtual warehouse, the plan status will change to completed after the virtual warehouse is manually deleted.
   • If a periodic addition or deletion plan is associated with a read-only virtual warehouse, the next execution time in the deletion column of the plan will automatically change to the next period or the end time after the virtual warehouse is manually deleted.

5. After confirming that the information is correct, enter DELETE or click Auto Enter and click OK to delete the cluster.