The MySQL connector allows querying and creating tables in an external MySQL instance. This can be used to join data between different systems like MySQL and Hive, or between two different MySQL instances.
To connect to MySQL, you need:
MySQL 5.7, 8.0 or higher.
Network access from the Trino coordinator and workers to MySQL. Port 3306 is the default port.
To configure the MySQL connector, create a catalog properties file
etc/catalog named, for example,
mount the MySQL connector as the
Create the file with the following contents, replacing the
connection properties as appropriate for your setup:
connector.name=mysql connection-url=jdbc:mysql://example.net:3306 connection-user=root connection-password=secret
connection-url defines the connection information and parameters to pass
to the MySQL JDBC driver. The supported parameters for the URL are
available in the MySQL Developer Guide.
For example, the following
connection-url allows you to
configure the JDBC driver to interpret time values based on UTC as a timezone on
the server, and serves as a workaround for a known issue.
connection-password are typically required and
determine the user credentials for the connection, often a service user. You can
use secrets to avoid actual values in the catalog
Multiple MySQL servers#
You can have as many catalogs as you need, so if you have additional
MySQL servers, simply add another properties file to
with a different name, making sure it ends in
example, if you name the property file
creates a catalog named
sales using the configured connector.
Decimal type handling#
DECIMAL types with precision larger than 38 can be mapped to a Trino
by setting the
decimal-mapping configuration property or the
decimal_mapping session property to
allow_overflow. The scale of the resulting type is controlled via the
configuration property or the
decimal-rounding-mode session property. The precision is always 38.
By default, values that require rounding or truncation to fit will cause a failure at runtime. This behavior
is controlled via the
decimal-rounding-mode configuration property or the
property, which can be set to
UNNECESSARY (the default),
General configuration properties#
The following properties can be used to configure how data types from the connected data source are mapped to Trino data types and how the metadata is cached in Trino.
Configure how unsupported column data types are handled:
The respective catalog session property is
Allow forced mapping of comma separated lists of data types to convert to
Support case insensitive database and collection names
Duration for which metadata, including table and column statistics, is cached
0 (disabled caching)
Cache the fact that metadata, including table and column statistics, is not available
The MySQL connector provides a schema for every MySQL database.
You can see the available MySQL databases by running
SHOW SCHEMAS FROM mysql;
If you have a MySQL database named
web, you can view the tables
in this database by running
SHOW TABLES FROM mysql.web;
You can see a list of the columns in the
clicks table in the
using either of the following:
DESCRIBE mysql.web.clicks; SHOW COLUMNS FROM mysql.web.clicks;
Finally, you can access the
clicks table in the
SELECT * FROM mysql.web.clicks;
If you used a different name for your catalog properties file, use
that catalog name instead of
mysql in the above examples.
The connector supports pushdown for a number of operations:
Aggregate pushdown for the following functions:
The connector provides read access and write access to data and metadata in the MySQL database. In addition to the globally available and read operation statements, the connector supports the following statements:
WHERE clause is specified, the
DELETE operation only works if the
predicate in the clause can be fully pushed down to the data source.