.alter database policy caching command
Applies to: ✅ Microsoft Fabric ✅ Azure Data Explorer
Changes the database cache policy. To speed up queries, data is cached on processing nodes, SSD, or even in RAM. The cache policy allows your database to describe the data artifacts that it uses, so that more important data can take priority.
Permissions
You must have at least Database Admin permissions to run this command.
Syntax
.alter database DatabaseName policy caching PolicyParameter
Learn more about syntax conventions.
Parameters
| Name | Type | Required | Description |
|---|---|---|---|
| DatabaseName | string |
✔️ | The name of the database for which to alter the caching policy. |
| PolicyParameter | string |
✔️ | One or more policy parameters. For parameters, see cache policy. |
Returns
Returns a JSON representation of the policy.
Example
The following example sets the caching policy to include the last 30 days.
.alter database MyDatabase policy caching hot = 30d
Output
| PolicyName | EntityName | Policy | ChildEntities | EntityType |
|---|---|---|---|---|
| CachingPolicy | database1 | {"DataHotSpan": {"Value": "30.00:00:00"},"IndexHotSpan": { "Value": "30.00:00:00" }} |
Define hot-cache windows
This command sets the caching policy to include the last 30 days and additional data from January and April 2021.
.alter database MyDatabase policy caching
hot = 30d,
hot_window = datetime(2021-01-01) .. datetime(2021-02-01),
hot_window = datetime(2021-04-01) .. datetime(2021-05-01)
Output
| PolicyName | EntityName | Policy | ChildEntities | EntityType |
|---|---|---|---|---|
| CachingPolicy | {"DataHotSpan": { "Value": "30.00:00:00" }, "IndexHotSpan": { "Value": "30.00:00:00" },"HotWindows": [{ "MinValue": "2021-01-01T00:00:00Z", "MaxValue": "2021-02-01T00:00:00Z" }, { "MinValue": "2021-04-01T00:00:00Z", "MaxValue": "2021-05-01T00:00:00Z" }]} |