Realtime Compute for Apache Flink:Manage Hologres catalogs

Create a Hologres catalog on the UI (recommended)

1. Go to the Catalogs page.

   1. Log on to the Realtime Compute for Apache Flink console. On the Fully Managed Flink tab, find the workspace that you want to manage and click Console in the Actions column.

   2. In the left-side navigation pane, click Catalogs.

2. On the Catalog List page, click Create Catalog. In the Create Catalog dialog box, click Hologres on the Built-in Catalog tab in the Choose Catalog Type step and click Next.

3. Configure the parameters in the Configure Catalog step.

   Important

   After you create a Hologres catalog, the parameter configuration cannot be modified. If you want to modify the parameter configuration, you must drop the Hologres catalog that you created and create a Hologres catalog again.

   

   Parameter	Description	Required
   catalogname	The name of the Hologres catalog.	Yes
   endpoint	The endpoint of the Hologres instance. For more information, see Instance configurations.	Yes
   username	The AccessKey ID of the Alibaba Cloud account. Note The Alibaba Cloud account to which the AccessKey ID belongs must be able to access all Hologres databases. For more information about Hologres database permissions, see Overview.	Yes
   password	The AccessKey secret of the Alibaba Cloud account.	Yes
   dbname	The name of the default Hologres database that you want to access.	Yes

4. Click Confirm.

   Note

   You can view the catalog that you create in the Catalogs pane on the left side of the Catalog List page.

Create a Hologres catalog by executing an SQL statement

1. In the code editor of the Scripts tab on the SQL Editor page, enter the following statement to create a Hologres catalog:

   CREATE CATALOG <catalogname> WITH (
     'type' = 'hologres',
     'endpoint' = '<endpoint>', 
     'username' = '<AccessKey>',
     'password' = '<AccessSecret>',
     'dbname' = '<dbname>'
   );

   The following table describes the parameters.

   Parameter	Description	Required
   catalogname	The name of the Hologres catalog. The name can contain only lowercase letters and digits. It cannot contain uppercase letters or special characters such as hyphens (-) and underscores (_).	Yes
   type	The type of the catalog. Set the value to hologres.	Yes
   endpoint	The endpoint of the Hologres instance. For more information, see Instance configurations.	Yes
   username	The AccessKey ID of the Alibaba Cloud account. Note The Alibaba Cloud account to which the AccessKey ID belongs must be able to access all Hologres databases. For more information about Hologres database permissions, see Overview.	Yes
   password	The AccessKey secret of the Alibaba Cloud account.	Yes
   dbname	The name of the default Hologres database that you want to access.	Yes
   ignore-non-persisted-options	Specifies whether to ignore non-persistence options when you use a Hologres catalog to create a table that uses non-persistence options. Valid values: true: The table can be created and all non-persistence options are ignored. This is the default value. false: An error that indicates that the table fails to be created is returned. Note The persistence of Hologres catalog table options allows the system to reacquire the consistent information that is specified in the DDL statement when the system reads the table information from the catalog again. Only the following persistence options are supported: endpoint, username, password, and dbname.	No
   Other parameters supported by the Hologres connector	In Realtime Compute for Apache Flink whose engine version is vvr-6.0.3-flink-1.15 or later, when you create a Hologres catalog, you can configure the parameters, such as the parameters in the WITH clause of a DDL statement that is used to create a Hologres table. If you configure the parameters for the catalog, the parameters are automatically configured for the table in the Hologres catalog. Note If you want to configure the parameters, you must set the ignore-non-persisted-options parameter to true. In Realtime Compute for Apache Flink whose engine version is earlier than vvr-6.0.3-flink-1.15, you can only use SQL hints to configure the parameters for each table.	No

2. Select the code that is used to create a catalog and click Run that appears on the left side of the code.

   

Create a Hologres table on the UI

1. Go to the Catalogs page.

   1. Log on to the Realtime Compute for Apache Flink console.

   2. On the Fully Managed Flink tab, find the workspace that you want to manage and click Console in the Actions column.

   3. In the left-side navigation pane, click Catalogs.

2. On the Catalog List page, find the desired catalog and click View in the Actions column.

3. On the page that appears, find the desired database and click View in the Actions column.

4. On the page that appears, click Create Table.

5. On the Built-in tab of the Create Table dialog box, click Connection Type and select a table type.

6. Click Next.

7. Enter the table creation statement and configure related parameters. Sample code:

   CREATE TABLE `${catalog_name}`.`${db_name}`.`${table_name}` (
    id INT,
    name STRING
   ) WITH (
    'connector' = 'hologres'
   );

8. Click Confirm.

Create a Hologres table by executing an SQL statement

1. In the code editor of the Scripts tab on the SQL Editor page, enter the following statement:

   You can use one of the following methods to create a Hologres table:

   • Execute the USE CATALOG HoloName statement to directly reference the information of the Hologres service.

     USE CATALOG ${catalog_name};
     CREATE TABLE `${db_name}`.`${schema_name.table_name}`(
       ...
      ) WITH (
        'connector' = 'hologres'
      );

     For more information about the USE syntax, see USE statements.

   • Directly reference the information about the Hologres service in DDL statements.

     CREATE TABLE `${catalog_name}`.`${db_name}`.`${schema_name.table_name}` (
       ...
     ) WITH (
       'connector' = 'hologres'
     );

   • Configure physical table properties in DDL statements.

     CREATE TABLE `${catalog_name}`.`${db_name}`.`${schema_name.table_name}` (
       ...
     ) WITH (
       'connector' = 'hologres',
       'table_property.orientation' = 'column',
       'table_property.distribution_key' = 'a',
       'table_property.clustering_key' = 'b:desc',
       'table_property.bitmap_columns' = 'a,b',
       'table_property.segment_key' = 'c',
       'table_property.time_to_live_in_seconds' = '86400',
       'table_property.binlog.level' = 'replica',
       'table_property.binlog.ttl' = '86400'
     );

     Note

     • When you create a table for a registered Hologres service, you must set the connector parameter to hologres in the WITH clause. Other parameters such as endpoint are optional.

     • When you create a Hologres table, specific physical table attributes of the table that you specify in the WITH clause cannot be modified.

     • Realtime Compute for Apache Flink whose engine version is earlier than vvr-6.0.3-flink-1.15 does not allow you to modify the physical table properties that are specified in the WITH clause when you create a physical table. You can log on to the Hologres console to modify the physical table properties. Only Realtime Compute for Apache Flink whose engine version is vvr-6.0.3-flink-1.15 or later allows you to modify physical table properties.

     • You cannot add or modify parameters in the WITH clause in a DDL statement that is used to create a Hologres table. You can use SQL hints to add or modify these parameters in the INSERT statement.

     • Realtime Compute for Apache Flink whose engine version is vvr-6.0.5-flink-1.15 or later allows you to configure column descriptions when you create a Hologres table. This way, the related physical table inherits the column descriptions of the Hologres table.

2. Select the table creation statement and click Run that appears on the left side of the code.

   

Drop a Hologres catalog on the UI

1. Go to the Catalogs page.

   1. Log on to the Realtime Compute for Apache Flink console.

   2. On the Fully Managed Flink tab, find the workspace that you want to manage and click Console in the Actions column.

   3. In the left-side navigation pane, click Catalogs.

2. On the Catalog List page, find the desired catalog and click Delete in the Actions column.

3. In the message that appears, click Delete.

   Note

   After you drop the catalog, you can view the Catalogs pane on the left side of the Catalog List page to check whether the catalog is dropped.

Drop a Hologres catalog by executing an SQL statement

1. In the code editor of the Scripts tab on the SQL Editor page, enter the following statement:

   DROP CATALOG ${catalog_name}

   catalog_name is the name of the Hologres catalog that you want to drop from the console of fully managed Flink.

   Warning

   The drop operation does not affect the deployments that are running. However, deployments that are not published or deployments that you want to suspend and then resume are affected. Proceed with caution.

2. Right-click the statement that is used to drop the catalog and select Run from the short-cut menu.

3. View the Catalogs pane to check whether the catalog is dropped.