Map metadata to Hologres-DataWorks(DataWorks)-阿里云帮助中心

To accelerate queries on MaxCompute data, use a Map Metadata to Hologres node to map MaxCompute table metadata to Hologres. This creates Hologres external tables that accelerate queries on MaxCompute data.

Prerequisites

You must have a MaxCompute project that contains the metadata you want to map.
You have created a Hologres instance and bound it as a Hologres computing resource.
Note
When you bind the Hologres computing resource, a data source with the same name is automatically created.

Limitations

You can only map the metadata of MaxCompute tables to Hologres external tables.
You can only run this node task manually in Data Studio.

Create a node

Create a Map Metadata to Hologres node.

Configure the node

To configure the node, specify the destination information, source information, and advanced options.

Configure destination information

Use the following parameters to configure the destination database and tables.

Parameter	Description
Destination Name	Select the destination Hologres data source. To manage or authorize Hologres data sources, use the Pages for Managing Destination feature on the left.
Destination Database	Select the destination Hologres database.
Schema	Select the destination schema. The default schema is `public`.

Configure source information

Use the following parameters to configure the source information.

Parameter		Description
Type		The default type is MaxCompute.
Servers		After a Hologres instance is created, a server named `odps_server` is automatically created. You can use it directly.
Source Project		Enter the name of the source MaxCompute project.
Select Tables for Query Acceleration	All Tables in Database	Select this option to map the metadata of all tables from the source MaxCompute project to the destination Hologres database.
	Selected Tables	To accelerate queries for specific tables, select Selected Tables. You can then enter a table name prefix in the search box on the right and select the required tables from the list below. Note The list can display a maximum of 200 tables. Any tables beyond this limit are not displayed.

Configure advanced options

Configure how to handle table name conflicts and unsupported data types.

Parameter

Description

Action for Table Name Conflicts

The following three options are supported:

Ignore and continue to create other tables.
Update the table with the same name.
Report an error and do not create the table again.

Data type not supported

The following two policies are supported:

Report an error and fail the import task.
Ignore and skip unsupported columns.

Run the node

Configure the runtime settings for the node.

Configure node properties.

In the Run Configuration panel on the right side of the node editor, configure the Compute Resource and Resource Group. The following table describes the parameters.

Parameter	Description
Resource Group	Select the resource group that you used to bind the Hologres computing resource. This group must have passed the connectivity test.
CUs for Scheduling	Specify the number of Computing CUs required to run the task. The default value is `0.25`.
Parameters	If you define variables in the `${Parameter Name}` format, specify the corresponding Parameter name and Parameter Value in the Script Parameters section. During runtime, the task replaces these variables with their specified values. For more information, see node scheduling.

To run the node, click Save and then Run.