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Applies to: ✅ 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.
You must have at least Database Admin permissions to run this command.
.alter
database
DatabaseName policy
caching
PolicyParameter
Learn more about syntax conventions.
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 a JSON representation of the policy.
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" }} |
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" }]} |