Apache Gravitino Trino connector - MySQL catalog

The MySQL catalog allows querying and creating tables in an external MySQL instance. You can join data between different systems like MySQL and Hive, or between two different MySQL instances by this.

Requirements

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.

Create table

At present, the Apache Gravitino Trino connector only supports basic MySQL table creation statements, which involve fields, null allowances, comments, primary keys, indexes, default values and auto-increment.

The Gravitino Trino connector does not support CREATE TABLE AS SELECT.

Alter table

Support for the following alter table operations:

• Rename table
• Add a column
• Drop a column
• Change a column type
• Set a table property

Select

The Gravitino Trino connector supports most SELECT statements, allowing the execution of queries successfully. Currently, it doesn't support certain query optimizations, such as indexes and pushdowns.

Update

Only UPDATE statements with constant assignments and predicates are supported. See also UPDATE limitation.

Delete

If the WHERE clause is specified, only the matching rows are deleted. Otherwise, all rows from the table are deleted. See also DELETE limitation.

Table and Schema properties

MySQL's schemas cannot support properties.

The following are supported MySQL table properties:

Property name	Type	Default Value	Description	Required	Since Version
engine	string	InnoDB	The engine that MySQL table uses.	No	0.4.0
auto_increment_offset	string	(none)	The auto increment offset for the table.	No	0.4.0
primary_key	list	(none)	The primary keys for the table, can choose multi columns as the table primary key. All key columns must be defined as NOT NULL.	No	1.0.0
unique_key	list	(none)	The unique keys for the table, can choose multi columns for multi unique key. Each unique key should be defined as keyName:col1,col2.	No	1.0.0

The following are supported MySQL column properties:

Property name	Type	Default Value	Description	Required	Since Version
auto_increment	boolean	false	The auto increment column.	No	1.0.0
default	string	(none)	The default value for column.	No	1.0.0

Note: Currently, creating tables only supports constant default values and does not support expression default values, and show create table also exclusively renders constant default values in its output. The following are Trino type which support configuration of default values:

Type name	Default Value example
TINYINT	1
SMALLINT	1
INT	1
BIGINT	1
REAL	1.0
DOUBLE	1.0
DECIMAL	1.0
VARCHAR	abc
CHAR	abc
DATE	2025-08-07
TIME	01:01:01
TIMESTAMP	2025-08-07 01:01:01 (CURRENT_TIMESTAMP)

Basic usage examples

You need to do the following steps before you can use the MySQL catalog in Trino through Gravitino.

• Create a metalake and catalog in Gravitino. Assuming that the metalake name is test and the catalog name is mysql_test, then you can use the following code to create them in Gravitino:

curl -X POST -H "Content-Type: application/json" \
-d '{
  "name": "test",
  "comment": "comment",
  "properties": {}
}' http://gravitino-host:8090/api/metalakes

curl -X POST -H "Content-Type: application/json" \
-d '{
  "name": "mysql_test",
  "type": "RELATIONAL",
  "comment": "comment",
  "provider": "jdbc-mysql",
  "properties": {
    "jdbc-url": "jdbc:mysql://mysql-host:3306?useSSL=false",
    "jdbc-user": "<username>",
    "jdbc-password": "<password>"
    "jdbc-driver": "com.mysql.cj.jdbc.Driver"
  }
}' http://gravitino-host:8090/api/metalakes/test/catalogs

For More information about the MySQL catalog, please refer to MySQL catalog.

• Set the value of configuration gravitino.metalake to the metalake you have created, named 'test', and start the Trino container.

Use the Trino CLI to connect to the Trino container and run a query.

Listing all Gravitino managed catalogs:

SHOW CATALOGS;

The results are similar to:

    Catalog
----------------
 gravitino
 jmx
 system
 mysql_test
(4 rows)

Query 20231017_082503_00018_6nt3n, FINISHED, 1 node

The gravitino catalog is a catalog defined By Trino catalog configuration. The mysql_test catalog is the catalog created by you in Gravitino. Other catalogs are regular user-configured Trino catalogs.

Creating tables and schemas

Create a new schema named database_01 in test.mysql_test catalog.

CREATE SCHEMA mysql_test.database_01;

Create a new table named table_01 in schema mysql_test.database_01.

CREATE TABLE mysql_test.database_01.table_01
(
name varchar,
salary int
);

Create a new table named table_index in schema mysql_test.database_01 with primary keys and indexes.

CREATE TABLE mysql_test.database_01.table_index (
   key1 integer NOT NULL,
   key2 integer,
   key3 integer,
   key4 integer,
   key5 integer NOT NULL,
   col1 integer
)
COMMENT ''
WITH (
   engine = 'InnoDB',
   primary_key = ARRAY['key5','key1'],
   unique_key = ARRAY['unique_key1:key2','unique_key2:key4,key3']
);

Create a new table named table_column_properties in schema mysql_test.database_01 with auto_increment and default.

CREATE TABLE mysql_test.database_01.table_column_properties(
    key1 INT NOT NULL WITH (auto_increment=true),
    f1 VARCHAR(200) WITH (default='VARCHAR'),
    f2 CHAR(20) WITH (default='CHAR') ,
    f4 DECIMAL(10, 3) WITH (default='0.3') ,
    f5 REAL WITH (default='0.3') ,
    f6 DOUBLE WITH (default='0.3') ,
    f8 TINYINT WITH (default='1') ,
    f9 SMALLINT WITH (default='1') ,
    f10 INT WITH (default='1') ,
    f11 INTEGER WITH (default='1') ,
    f12 BIGINT WITH (default='1'),
    f13 DATE WITH (default='2024-04-01'),
    f14 TIME WITH (default='08:00:00'),
    f15 TIMESTAMP WITH (default='2012-12-31 11:30:45'),
    f16 TIMESTAMP WITH TIME ZONE WITH (default='2012-12-31 11:30:45'),
    f17 TIMESTAMP WITH TIME ZONE WITH (default='CURRENT_TIMESTAMP')
)
WITH (
   primary_key = ARRAY['key1']
);

Writing data

Insert data into the table table_01:

INSERT INTO mysql_test.database_01.table_01 (name, salary) VALUES ('ice', 12);

Insert data into the table table_01 from select:

INSERT INTO mysql_test.database_01.table_01 (name, salary) SELECT * FROM "test.mysql_test".database_01.table_01;

Update the table table_01:

UPDATE mysql_test.database_01.table_01 SET name = 'ice_update' WHERE salary = 12;

Delete the table table_01:

DELETE FROM mysql_test.database_01.table_01 WHERE salary = 12;
DELETE FROM mysql_test.database_01.table_01;

Querying data

Query the table_01 table:

SELECT * FROM mysql_test.database_01.table_01;

Modify a table

Add a new column age to the table_01 table:

ALTER TABLE mysql_test.database_01.table_01 ADD COLUMN age int;

Drop a column age from the table_01 table:

ALTER TABLE mysql_test.database_01.table_01 DROP COLUMN age;

Rename the table_01 table to table_02:

ALTER TABLE mysql_test.database_01.table_01 RENAME TO mysql_test.database_01.table_02;

DROP

Drop a schema:

DROP SCHEMA mysql_test.database_01;

Drop a table:

DROP TABLE mysql_test.database_01.table_01;