E-MapReduce:MySQL connector

Minimum required configuration

Each MySQL catalog is defined by a .properties file. The minimum configuration requires three properties:

connection-url=jdbc:mysql://rm-2ze5ipacsu8265q****.mysql.rds.aliyuncs.com:3306
connection-user=<your-username>
connection-password=<your-password>

To find your connection-url, see View and manage instance endpoints and ports.

In the EMR console, these properties map to configuration items on the mysql.properties tab of the Trino service's Configure tab.

Connect to multiple MySQL instances

To connect Trino to more than one MySQL instance, create a separate .properties file for each instance in the etc/catalog directory. Each file name becomes the catalog name in Trino — for example, sales.properties creates a catalog named sales.

File names must be unique and end with .properties.

To add a second MySQL catalog using the EMR console:

1. On the Configure tab of the Trino service, click the mysql.properties tab. Set connection-url, connection-user, and connection-password for your first MySQL instance. To add properties not listed by default, click Add Configuration Item at the top of the tab. For details, see the Add configuration items section of "Manage configuration items".

2. Click the connector[x].properties tab (where x is an integer starting from 1) to configure additional MySQL catalogs. Repeat for each additional instance.

3. Save the configuration:

   1. At the bottom of the Configure tab, click Save.

   2. In the dialog box, enter a reason in Execution Reason and click Save.

4. Restart the Trino service:

   1. In the upper-right corner, choose More > Restart.

   2. Enter a reason in Execution Reason and click OK.

   3. In the Confirm dialog, click OK.

DECIMAL type with precision greater than 38

MySQL's DECIMAL type supports precision up to 65, but Trino's DECIMAL type supports a maximum precision of 38. To map a MySQL DECIMAL(p, s) where p > 38, set the decimal_mapping configuration property (or the corresponding session property) to allow_overflow. The mapped Trino type uses a fixed precision of 38; the scale is controlled by decimal-default-scale and the rounding behavior by decimal-rounding-mode.

By default, any value that requires rounding or truncation during mapping causes a runtime failure. Set decimal-rounding-mode to one of the following values to change this behavior:

General configuration properties

Use the following properties to control how unsupported data types are handled and how metadata is cached.