.alter query acceleration policy command (preview)
Applies to: ✅ Microsoft Fabric ✅ Azure Data Explorer
Alters the query acceleration policy of a specific external delta table.
For limitations, see Limitations.
Permissions
You must have at least Database Admin permissions to run this command.
Syntax
.alter external table ExternalTableName policy query_acceleration 'JSON-serialized policy'
Parameters
| Name | Type | Required | Description |
|---|---|---|---|
| ExternalTableName | string |
✔️ | The name of the external delta table. |
| JSON-serialized policy | string |
✔️ | String literal holding a JSON property bag. |
JSON property bag
| Property | Type | Required | Description |
|---|---|---|---|
| IsEnabled | Boolean |
✔️ | Indicates whether the policy is enabled. |
| Hot | Timespan |
✔️ | The hot period defined in the query acceleration policy. Minimum value = 1 d. |
Note
Query acceleration is applied to data within a specific time period, defined as timespan, starting from the modificationTime as stated for each file in the delta log.
Example
{"IsEnabled": true, "Hot": "1.00:00:00"}
Returns
The command returns a table with one record that includes the modified policy object.
| Column | Type | Description |
|---|---|---|
| PolicyName | string |
The name of the policy - QueryAcceleration |
| EntityName | string |
The fully qualified name of the entity: [DatabaseName].[ExternalTableName] |
| Policy | string |
A JSON-serialization of the query acceleration policy that is set on the external delta table |
| ChildEntities | string |
The child entities this policy affects - null |
| EntityType | string |
The type of the entity the policy applies to - ExternalTable |
Example
.alter external table MyExternalTable policy query_acceleration '{"IsEnabled": true, "Hot": "1.00:00:00"}'