enable_large_strings_opt_in - Amazon Redshift
Values (default in bold)Description
Services or capabilities described in AWS documentation might vary by Region. To see the differences applicable to the AWS European Sovereign Cloud Region, see the AWS European Sovereign Cloud User Guide.

Amazon Redshift will no longer support the use of Python UDFs after June 30, 2026. We will start enforcing it in phases. For more information on the details of Python end of life and migration options, see the blog post that was published on June 30, 2025.

enable_large_strings_opt_in

Values (default in bold)

Yes, No, not set (preserves existing cluster behavior)

Description

Determines whether Amazon Redshift supports individual strings up to 16,000,000 bytes in the SUPER data type and in-memory string operations.

When set to Yes:

  • Individual strings that you store in the SUPER data type can be up to 16,000,000 bytes.

  • In-memory string functions can process VARCHAR values up to 16,000,000 bytes.

  • VARCHAR(MAX) resolves to VARCHAR(16000000) in expression contexts, such as CAST expressions, views, user-defined functions (UDFs), and stored procedures.

  • CREATE TABLE with VARCHAR(MAX) continues to create VARCHAR(65535) columns.

When set to No:

  • Individual strings in SUPER columns have a limit of 65,535 bytes.

  • String functions can process VARCHAR values up to 65,535 bytes.

When this parameter is not set, Amazon Redshift preserves the existing behavior of your cluster.

For a provisioned cluster, you must reboot the cluster to apply this parameter. To check the current state of your cluster, run the following command:

SELECT is_large_string_enabled();

When you reset enable_large_strings_opt_in through ResetClusterParameterGroup, Amazon Redshift preserves the original value of the parameter. After you set enable_large_strings_opt_in to Yes or No, you can't reset it to the default value.