Starburst Redshift connector#

The Starburst Redshift connector is an extended version of the Redshift connector. It can be used to connect and query Redshift databases. Configuration and usage is identical.

The following improvements are included:

Requirements#

Fulfill the Redshift connector requirements.
Additional features of the connector require a valid Starburst Enterprise license, unless otherwise noted.

Configuration#

The connector configuration is identical to the configuration for the base Redshift connector.

A minimal configuration, with the connector-name redshift and the JDBC connections details, is shown in the following snippet:

connector.name=redshift
connection-url=jdbc:redshift://example.net:5439/database
connection-user=redshift_username
connection-password=redshift_password

Type mapping#

Because SEP and Redshift each support types that the other does not, this connector modifies some types when reading or writing data.

Redshift to SEP read type mapping#

This connector supports reading the following Redshift types and performs conversion to SEP types with the detailed mappings as shown in the following table.

Redshift to SEP type mapping#
Redshift database type	SEP type	Notes
`BOOLEAN`	`BOOLEAN`
`SMALLINT`, `INT2`	`SMALLINT`
`INTEGER`, `INT`, `INT4`	`INTEGER`
`BIGINT`, `INT8`	`BIGINT`
`DOUBLE PRECISION`, `FLOAT`, `FLOAT8`	`DOUBLE`
`REAL`, `FLOAT4`	`REAL`
`DECIMAL(p, s)`, `NUMERIC(p,s)`	`DECIMAL(p, s)`
`CHAR(n)`, `NCHAR(n)`, `BPCHAR`	`CHAR(n)`	Redshift’s `BPCHAR` is equivalent to `CHAR(256)`.
`VARCHAR(n)`, `NVARCHAR(n)`, `TEXT`	`VARCHAR(n)`	Redshift’s `TEXT` is equivalent to `VARCHAR(256)`.
`DATE`	`DATE`	See Mapping datetime types
`TIME`	`TIME(6)`	See Mapping datetime types
`TIMESTAMP`	`TIMESTAMP(6)`	See Mapping datetime types

No other types are supported.

SEP to Redshift write type mapping#

This connector supports writing the following SEP types and performs conversion to Redshift types with the detailed mappings as shown in the following table.

SEP to Redshift type mapping#
SEP type	Redshift type	Notes
`BOOLEAN`	`BOOLEAN`
`TINYINT`	`SMALLINT`
`SMALLINT`	`SMALLINT`
`INTEGER`	`INTEGER`
`BIGINT`	`BIGINT`
`REAL`	`REAL`
`DOUBLE`	`DOUBLE PRECISION`
`DECIMAL(p, s)`	`DECIMAL(p, s)`
`CHAR(n)`	`CHAR(n)`	For `n` up to 4096.
`CHAR(n)`	`VARCHAR(n)`	For `n` from 4096 to 65535.
`CHAR(n)`	`VARCHAR(MAX)`	For `n` above 65535.
`VARCHAR(n)`	`VARCHAR(n)`	For `n` up to 65535.
`VARCHAR(n)`	`VARCHAR(MAX)`	For `n` above 65535.
`VARCHAR`	`VARCHAR(MAX)`	When no bound is given.
`DATE`	`DATE`	See Mapping datetime types
`TIME(p)`	`TIME`	See Mapping datetime types
`TIMESTAMP(p)`	`TIMESTAMP`	See Mapping datetime types

No other types are supported.

Mapping datetime types#

Redshift’s TIME and TIMESTAMP types only support microsecond precision (6 digits). When writing data with higher precision from SEP to Redshift, the time is rounded to the nearest microsecond before being inserted.

Performance#

The connector includes a number of performance improvements, detailed in the following sections.

Pushdown#

The connector supports pushdown for a number of operations:

Aggregate pushdown for the following functions:

Table statistics#

The Redshift connector supports table and column statistics to improve query processing performance based on the actual data in the data source.

The statistics are collected by Redshift and retrieved by the connector.

ANALYZE may be run automatically depending on your Redshift configuration. To manually collect statistics for a table, execute the following statement in Redshift.

ANALYZE table_schema.table_name;

Refer to Redshift documentation for additional ANALYZE options.

Dynamic filtering#

Dynamic filtering is enabled by default. It causes the connector to wait for dynamic filtering to complete before starting a JDBC query.

You can disable dynamic filtering by setting the property dynamic-filtering.enabled in your catalog properties file to false.

Starburst Cached Views#

The connectors supports table scan redirection to improve performance and reduce load on the data source.

Security#

The connector includes a number of security-related features, detailed in the following sections.

User impersonation#

The connector supports user impersonation. Enable user impersonation in the catalog properties file:

redshift.impersonation.enabled=true

User impersonation in the Redshift connector is based on SET SESSION AUTHORIZATION command supported in Redshift.

Note

Running SET SESSION AUTHORIZATION in Redshift requires the initial connection user to be a superuser.

Password credential pass-through#

The connector supports password credential pass-through. To enable it, edit the catalog properties file to include the authentication type:

redshift.authentication.type=PASSWORD_PASS_THROUGH

For more information about configurations and limitations, see Password credential pass-through.

Limitations#

The Redshift connector doesn’t push down queries with a GROUP BY and WHERE clause on the same column for tables using ALL or AUTO(ALL) distribution styles due to a limitation in Redshift. You can work around this by changing the table to use an EVEN or KEY distribution style as described in the Redshift documentation about distribution styles.