Trino

If you are using Trino for distributed SQL query processing and wish to use it to connect to SQreamDB, follow these instructions.

Before You Begin

It is essential you have the following installed:

  • SQreamDB version 4.1 or later

  • Trino version 403 or later

  • Trino Connector

  • JDBC version 4.5.6 or later

Installation

The Trino Connector must be installed on each cluster node dedicated to Trino.

  1. Create a dedicated directory for the Trino Connector.

  2. Download the Trino Connector and extract the content of the ZIP file to the dedicated directory.

Connecting to SQreamDB

Trino uses catalogs for referencing stored objects such as tables, databases, and functions. Each Trino catalog may be configured with access to a single SQreamDB database. If you wish Trino to have access to more than one SQreamDB database or server, you must create additional catalogs.

Catalogs may be created using properties files. Start by creating a sqream.properties file and placing it under trino-server/etc/catalog.

The following is an example of a properties file:

connector.name=<name>
connection-url=jdbc:Sqream://<host and port>/<database name>;[<optional parameters>; ...]
connection-user=<user>
connection-password=<password>

Supported Data Types and Mapping

Use the appropriate Trino data type for executing queries. Upon execution, incompatible data types will be converted by Trino to SQreamDB data types.

Trino type

SQreamDB type

BOOLEAN

BOOL

TINYINT

TINYINT

SMALLINT

SMALLINT

INT

INT

BIGINT

BIGINT

REAL

REAL

DOUBLE

DOUBLE

DATE

DATE

TIMESTAMP

DATETIME

VARCHAR

TEXT

DECIMAL(P,S)

NUMERIC(P,S)

Examples

The following is an example of the SHOW SCHEMAS FROM statement:

SHOW SCHEMAS FROM sqream;

The following is an example of the SHOW TABLES FROM statement:

SHOW TABLES FROM sqream.public;

The following is an example of the DESCRIBE sqream.public.t statement:

DESCRIBE sqream.public.t;

Limitations

The Trino Connector does not support the following SQL statements:

  • GRANT

  • REVOKE

  • SHOW GRANTSHOW ROLES

  • SHOW ROLE GRANTS