Apache Doris catalog

Introduction

Apache Gravitino provides the ability to manage Apache Doris metadata through JDBC connection.

caution

Gravitino saves some system information in schema and table comments, 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 Doris instance.
• Supports metadata management of Doris (1.2.x).
• Supports table index.
• Supports column default value.

Catalog properties

You can pass to a Doris 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.

You can check the relevant data source configuration in data source properties for more details.

Besides the common catalog properties, the Doris 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:9030	(none)	Yes	0.5.0
jdbc-driver	The driver of the JDBC connection. For example, com.mysql.jdbc.Driver.	(none)	Yes	0.5.0
jdbc-user	The JDBC user name.	(none)	Yes	0.5.0
jdbc-password	The JDBC password.	(none)	Yes	0.5.0
jdbc.pool.min-size	The minimum number of connections in the pool. 2 by default.	2	No	0.5.0
jdbc.pool.max-size	The maximum number of connections in the pool. 10 by default.	10	No	0.5.0
jdbc.pool.max-size	The maximum number of connections in the pool. 10 by default.	10	No	0.5.0
replication_num	The number of replications for the table. If not specified and the number of backend servers less than 3, then the default value is 1; If not specified and the number of backend servers greater or equals to 3, the default value (3) in Doris server will be used. For more, please see the doc	1 or 3	No	0.6.0-incubating

Before using the Doris Catalog, you must download the corresponding JDBC driver to the catalogs/jdbc-doris/libs directory. Gravitino doesn't package the JDBC driver for Doris due to licensing issues.

Catalog operations

Refer to Manage Relational Metadata Using Gravitino for more details.

Schema

Schema capabilities

• Gravitino's schema concept corresponds to the Doris database.
• Supports creating schema.
• Supports dropping schema.

Schema properties

• Support schema properties, including Doris database properties and user-defined properties.

Schema operations

Please refer to Manage Relational Metadata Using Gravitino for more details.

Table

Table capabilities

• Gravitino's table concept corresponds to the Doris table.
• Supports index.
• Supports column default value.

Table column types

Gravitino Type	Doris Type
Boolean	Boolean
Byte	TinyInt
Short	SmallInt
Integer	Int
Long	BigInt
Float	Float
Double	Double
Decimal	Decimal
Date	Date
Timestamp	Datetime
VarChar	VarChar
FixedChar	Char
String	String

Doris doesn't support Gravitino Fixed Timestamp_tz IntervalDay IntervalYear Union UUID type. The data types other than those listed above are mapped to Gravitino's Unparsed Type that represents an unresolvable data type since 0.5.0.

note

Gravitino can not load Doris array, map and struct type correctly, because Doris doesn't support these types in JDBC.

Table column auto-increment

Unsupported for now.

Table properties

• Doris supports table properties, and you can set them in the table properties.
• Only supports Doris table properties and doesn't support user-defined properties.

Table indexes

• Supports PRIMARY_KEY

  Please be aware that the index can only apply to a single column.

  Json

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

  Java

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

Table partitioning

The Doris catalog supports partitioned tables. Users can create partitioned tables in the Doris catalog with specific partitioning attributes. It is also supported to pre-assign partitions when creating Doris tables. Note that although Gravitino supports several partitioning strategies, Apache Doris inherently only supports these two partitioning strategies:

• RANGE
• LIST

caution

The fieldName specified in the partitioning attributes must be the name of columns defined in the table.

Table distribution

Users can also specify the distribution strategy when creating tables in the Doris catalog. Currently, the Doris catalog supports the following distribution strategies:

• HASH
• RANDOM

For the RANDOM distribution strategy, Gravitino uses the EVEN to represent it. More information about the distribution strategy defined in Gravitino can be found here.

Table operations

Please refer to Manage Relational Metadata Using Gravitino for more details.

Alter table operations

Gravitino supports these table alteration operations:

• RenameTable
• UpdateComment
• AddColumn
• DeleteColumn
• UpdateColumnType
• UpdateColumnPosition
• UpdateColumnComment
• SetProperty

Please be aware that:

• Not all table alteration operations can be processed in batches.
• Schema changes, such as adding/modifying/dropping columns can be processed in batches.
• Supports modifying multiple column comments at the same time.
• Doesn't support modifying the column type and column comment at the same time.
• The schema alteration in Doris is asynchronous. You might get an outdated schema if you execute a schema query immediately after the alteration. It is recommended to pause briefly after the schema alteration. Gravitino will add the schema alteration status into the schema information in the upcoming version to solve this problem.