| title | Preview Features FAQ | |
|---|---|---|
| description | Frequently asked questions about the PREVIEW_FEATURES opt-in mechanism. | |
| author | yorek | |
| ms.author | damauri | |
| ms.reviewer | mikeray, randolphwest | |
| ms.date | 11/18/2025 | |
| ms.service | sql | |
| ms.subservice | release-landing | |
| ms.topic | release-notes | |
| ms.custom |
|
|
| monikerRange | >=sql-server-ver17 |
[!INCLUDE sqlserver2025]
[!INCLUDE sssql25-md] introduces the PREVIEW_FEATURES database scoped configuration option. This option enables features that are available for preview.
[!INCLUDE preview-features]
Preview features that become generally available in a subsequent cumulative update no longer require the database-scoped configuration option.
PREVIEW_FEATURES is a database-scoped configuration that lets you try out new SQL Server features before they're generally available. This option is intended for development and testing environments and shouldn't be used in production.
PREVIEW_FEATURES is a DATABASE SCOPED CONFIGURATION option, therefore you can enable it by executing the following code:
ALTER DATABASE SCOPED CONFIGURATION
SET PREVIEW_FEATURES = ON;
GO
SELECT * FROM sys.database_scoped_configurations
WHERE [name] = 'PREVIEW_FEATURES'
GOFor more information, see ALTER DATABASE SCOPED CONFIGURATION.
No, most AI features in SQL Server 2025 are already generally available (GA), including AI_GENERATE_EMBEDDINGS, CREATE EXTERNAL MODEL, and the vector data type and related functions. Only the features explicitly listed in the release notes document require the PREVIEW_FEATURES option to be enabled.
No, enabling the PREVIEW_FEATURES configuration doesn't change the GA status of a database. The database remains GA even when preview features are enabled. This opt-in mechanism is designed to allow customers to test new features before they reach GA, without affecting the overall GA status of the database itself. However, it's important to note that after enabling preview features, if preview features are used and they involve persisted objects (like indexes), disabling PREVIEW_FEATURES later might cause errors unless those objects are removed or rebuilt.
Preview features should generally be used in development or testing environments, not in production, due to their experimental nature and potential for change.
Features are promoted to GA via a cumulative update (CU).
Yes. Preview features can be updated in CUs while remaining under the PREVIEW_FEATURES umbrella.
The feature becomes available regardless of the PREVIEW_FEATURES setting.
If no preview features were used, you can safely turn it off at any time. If preview features were used you can turn it OFF, but objects using those features will error out. Once the PREVIEW_FEATURES option is turned off, the database engine is unaware of those features so using them might return errors because the new commands aren't recognized at all.
No, the preview features setting doesn't affect database backup or restore. Databases remain compatible across cumulative updates and general releases. However, if you apply a cumulative update (CU) that improves a feature in preview and then restore that database to a previous version, the feature might not work as expected or might even error out. This is because the restored version might not recognize the updated syntax or behavior introduced in the newer CU. Therefore, while backup and restore operations themselves are unaffected, feature compatibility depends on the CU level of the target environment.
If at any point a preview feature requires changes that would make it incompatible with previous versions, we will clearly document those changes. In such cases, applying the update will require a manual step to ensure you're aware of the potential impact. Importantly, updates won't automatically make the database incompatible with previous versions. Even in these cases, we'll provide the ability to roll back to the previous CU if needed.
You can leave PREVIEW_FEATURES set to OFF. You retain full rollback and restore capabilities across CUs and GA. Any update to the features using the PREVIEW_FEATURES opt-in mechanism doesn't affect your database.
The database scoped setting enables the usage of all preview features.
Yes, support is provided for preview features, similar to What's new in Azure SQL Database?
GDR patches are orthogonal to CUs and don't affect the status of PREVIEW_FEATURES. Features moved to GA via CU require that CU to be applied; GDRs don't include feature payloads.