When you need to run fast queries on MaxCompute data without moving it, use the metadata mapping to Hologres node to map MaxCompute table metadata to Hologres. This creates Hologres external tables that point to your MaxCompute data, so you can query it through Hologres without data migration.
Prerequisites
Before you begin, make sure you have:
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A MaxCompute project whose metadata you want to map. See Create a project.
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A Hologres instance created and attached as a Hologres computing resource. Attaching a Hologres computing resource automatically generates a data source with the same name.
Limits
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Only mapping MaxCompute table metadata to Hologres external tables is supported.
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This node task can only be manually executed in Data Studio.
Create a node
Configure the node
Complete the destination information, source information, and advanced options.
Configure destination information
| Parameter | Description |
|---|---|
| Destination Connection | Select the target Hologres data source. To manage or authorize Hologres data sources, use Destination Management on the left. |
| Destination Database | Select the target Hologres database. |
| Schema | Select the target schema. The default is public. |
Configure source information
| Parameter | Description |
|---|---|
| Type | The default type is MaxCompute. |
| Server List | After a Hologres instance is created, a server named odps_server is automatically created. Use it directly. |
| Source Project | Enter the name of the MaxCompute project whose metadata you want to map. |
| Select Tables For Direct Acceleration | Choose the acceleration scope: Accelerate Entire Database maps all table metadata from the MaxCompute project to the target Hologres database. Partial Acceleration maps only the tables you select — enter a table name prefix to filter, then select from the list. The list displays a maximum of 200 tables. |
Configure advanced options
Use these settings to control how the node handles table name conflicts and unsupported data types during mapping.
| Parameter | Description |
|---|---|
| Table Name Conflict | The following three options are supported: Ignore, continue to create the rest tables. / Update, modify the same name tables. / Alert, do not duplicately create. |
| Unsupported Data Type | The following two policies are supported: Alert, import failure. / Ignore, skip unsupported columns. |
Run the node
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In Run Configuration on the right side of the sync node editing page, set the following parameters.
Parameter Description Resource Group Select the resource group that passed the connectivity test when you attached the Hologres computing resource. Computing CU Set the computing capacity for this task. The default value is 0.25.Parameters If you used the ${parameter_name}format in filter conditions, configure the corresponding Parameter Name and Parameter Value in the Script Parameters section. The values are substituted at runtime. For more information, see Node scheduling. -
Click Save, then click Run.