MySQL catalog

Introduction

Apache Gravitino provides the ability to manage MySQL metadata.

caution

Gravitino saves some system information in schema and table comment, like (From Gravitino, DO NOT EDIT: gravitino.v1.uid1078334182909406185), please don't change or remove this message.

Catalog

Catalog capabilities

• Gravitino catalog corresponds to the MySQL instance.
• Supports metadata management of MySQL (5.7, 8.0).
• Supports DDL operation for MySQL databases and tables.
• Supports table index.
• Supports column default value and auto-increment.
• Supports managing MySQL table features though table properties, like using engine to set MySQL storage engine.

Catalog properties

You can pass to a MySQL data source any property that isn't defined by Gravitino by adding gravitino.bypass. prefix as a catalog property. For example, catalog property gravitino.bypass.maxWaitMillis will pass maxWaitMillis to the data source property.

Check the relevant data source configuration in data source properties

When you use the Gravitino with Trino. You can pass the Trino MySQL connector configuration using prefix trino.bypass.. For example, using trino.bypass.join-pushdown.strategy to pass the join-pushdown.strategy to the Gravitino MySQL catalog in Trino runtime.

If you use a JDBC catalog, you must provide jdbc-url, jdbc-driver, jdbc-user and jdbc-password to catalog properties. Besides the common catalog properties, the MySQL catalog has the following properties:

Configuration item	Description	Default value	Required	Since Version
jdbc-url	JDBC URL for connecting to the database. For example, jdbc:mysql://localhost:3306	(none)	Yes	0.3.0
jdbc-driver	The driver of the JDBC connection. For example, com.mysql.jdbc.Driver or com.mysql.cj.jdbc.Driver.	(none)	Yes	0.3.0
jdbc-user	The JDBC user name.	(none)	Yes	0.3.0
jdbc-password	The JDBC password.	(none)	Yes	0.3.0
jdbc.pool.min-size	The minimum number of connections in the pool. 2 by default.	2	No	0.3.0
jdbc.pool.max-size	The maximum number of connections in the pool. 10 by default.	10	No	0.3.0

caution

You must download the corresponding JDBC driver to the catalogs/jdbc-mysql/libs directory.

Catalog operations

Refer to Manage Relational Metadata Using Gravitino for more details.

Schema

Schema capabilities

• Gravitino's schema concept corresponds to the MySQL database.
• Supports creating schema, but does not support setting comment.
• Supports dropping schema.
• Supports cascade dropping schema.

Schema properties

• Doesn't support any schema property settings.

Schema operations

Refer to Manage Relational Metadata Using Gravitino for more details.

Table

Table capabilities

• Gravitino's table concept corresponds to the MySQL table.
• Supports DDL operation for MySQL tables.
• Supports index.
• Supports column default value and auto-increment..
• Supports managing MySQL table features though table properties, like using engine to set MySQL storage engine.

Table column types

Gravitino Type	MySQL Type
Byte	Tinyint
Unsigned Byte	Tinyint Unsigned
Short	Smallint
Unsigned Short	Smallint Unsigned
Integer	Int
Unsigned Integer	Int Unsigned
Long	Bigint
Unsigned Long	Bigint Unsigned
Float	Float
Double	Double
String	Text
Date	Date
Time	Time
Timestamp	Timestamp
Decimal	Decimal
VarChar	VarChar
FixedChar	FixedChar
Binary	Binary

info

MySQL doesn't support Gravitino Boolean Fixed Struct List Map Timestamp_tz IntervalDay IntervalYear Union UUID type. Meanwhile, the data types other than listed above are mapped to Gravitino External Type that represents an unresolvable data type since 0.6.0-incubating.

Table column auto-increment

note

MySQL setting an auto-increment column requires simultaneously setting a unique index; otherwise, an error will occur.

Json

{
  "columns": [
    {
      "name": "id",
      "type": "integer",
      "comment": "id column comment",
      "nullable": false,
      "autoIncrement": true
    },
    {
      "name": "name",
      "type": "varchar(500)",
      "comment": "name column comment",
      "nullable": true,
      "autoIncrement": false
    }
  ],
  "indexes": [
    {
      "indexType": "primary_key",
      "name": "PRIMARY",
      "fieldNames": [["id"]]
    }
  ]
}

Java

Column[] cols = new Column[] {
    Column.of("id", Types.IntegerType.get(), "id column comment", false, true, null),
    Column.of("name", Types.VarCharType.of(500), "Name of the user", true, false, null)
};
Index[] indexes = new Index[] {
    Indexes.of(IndexType.PRIMARY_KEY, "PRIMARY", new String[][]{{"id"}})
}

Table properties

Although MySQL itself does not support table properties, Gravitino offers table property management for MySQL tables through the jdbc-mysql catalog, enabling control over table features. The supported properties are listed as follows:

Property Name	Description	Required	Since version
engine	The engine used by the table. The default value is InnoDB. For example MyISAM, MEMORY, CSV, ARCHIVE, BLACKHOLE, FEDERATED, ndbinfo, MRG_MYISAM, PERFORMANCE_SCHEMA.	No	0.4.0
auto-increment-offset	Used to specify the starting value of the auto-increment field.	No	0.4.0

• Doesn't support remove table properties. You can only modify values, not delete properties.

Table indexes

• Supports PRIMARY_KEY and UNIQUE_KEY.

note

The index name of the PRIMARY_KEY must be PRIMARY Create table index

Json

{
  "indexes": [
    {
      "indexType": "primary_key",
      "name": "PRIMARY",
      "fieldNames": [["id"]]
    },
    {
      "indexType": "unique_key",
      "name": "id_name_uk",
      "fieldNames": [["id"] ,["name"]]
    }
  ]
}

Java

Index[] indexes = new Index[] {
    Indexes.of(IndexType.PRIMARY_KEY, "PRIMARY", new String[][]{{"id"}}),
    Indexes.of(IndexType.UNIQUE_KEY, "id_name_uk", new String[][]{{"id"} , {"name"}}),
}

Table operations

Refer to Manage Relational Metadata Using Gravitino for more details.

Alter table operations

Gravitino supports these table alteration operations:

• RenameTable
• UpdateComment
• AddColumn
• DeleteColumn
• RenameColumn
• UpdateColumnType
• UpdateColumnPosition
• UpdateColumnNullability
• UpdateColumnComment
• UpdateColumnDefaultValue
• SetProperty

info

• You cannot submit the RenameTable operation at the same time as other operations.
• If you update a nullability column to non-nullability, there may be compatibility issues.