Skip to content

Commit b82f83a

Browse files
Merge pull request #2790 from MicrosoftDocs/main639001225741623340sync_temp
For protected branch, push strategy should use PR and merge to target branch method to work around git push error
2 parents 83f36f8 + d8159ca commit b82f83a

File tree

1 file changed

+15
-2
lines changed

1 file changed

+15
-2
lines changed

data-explorer/kusto/management/alter-query-acceleration-policy-command.md

Lines changed: 15 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -3,7 +3,7 @@ title: .alter query acceleration policy command
33
description: Learn how to use the .alter query acceleration policy command to accelerate queries over external delta tables.
44
ms.reviewer: sharmaanshul
55
ms.topic: reference
6-
ms.date: 09/16/2025
6+
ms.date: 11/30/2025
77
---
88

99
# `.alter query acceleration policy` command
@@ -30,17 +30,21 @@ You must have at least [Database Admin](../access-control/role-based-access-cont
3030
| _JSON-serialized policy_ | `string` | :heavy_check_mark: | String literal holding a [JSON property bag](#json-property-bag). |
3131

3232
### JSON property bag
33+
3334
::: moniker range="microsoft-fabric"
35+
3436
| Property | Type | Required | Description |
3537
| ------------------- | ---------- | ------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
3638
| IsEnabled | `Boolean` | :heavy_check_mark: | Indicates whether the policy is enabled. |
3739
| Hot | `Timespan` | :heavy_check_mark: | The hot period defined in the query acceleration policy. Minimum value = 1 d. |
3840
| HotWindows | `DateTime` | | One or more optional time windows. Delta data files created within these time windows are accelerated. |
3941
| MaxAge | `Timespan` | | The external table returns accelerated data if the last index refresh time is greater than @now - MaxAge. Otherwise, the external table operates in non-accelerated mode. Default is 5 minutes. Minimum is 1 minute. This property can also be overridden at query time by using the [`external_table()` function's](../query/external-table-function.md) `MaxAgeOverride` parameter. |
4042
| HotDateTimeColumn | `String` | | Optional. The name of a datetime column in the Delta table whose values will be used to determine hot-cache eligibility. When set, data files whose rows have values within the configured Hot period (and/or HotWindows) are selected for caching. |
43+
4144
::: moniker-end
4245

4346
::: moniker range="azure-data-explorer"
47+
4448
| Property | Type | Required | Description |
4549
| ------------------- | ---------- | ------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
4650
| IsEnabled | `Boolean` | :heavy_check_mark: | Indicates whether the policy is enabled. |
@@ -49,9 +53,12 @@ You must have at least [Database Admin](../access-control/role-based-access-cont
4953
| MaxAge | `Timespan` | | The external table returns accelerated data if the last index refresh time is greater than @now - MaxAge. Otherwise, the external table operates in non-accelerated mode. Default is 5 minutes. Minimum is 1 minute. This property can also be overridden at query time by using the [`external_table()` function's](../query/external-table-function.md) `MaxAgeOverride` parameter. |
5054
| ManagedIdentity | `string` | | Optional managed identity for which the query acceleration background operations are executed. This identity must have relevant delta table permissions and must be enabled for AutomatedFlows in the cluster / database managed identity policy. For more information, see [Managed identities overview](/azure/data-explorer/managed-identities-overview). |
5155
| HotDateTimeColumn | `String` | | Optional. The name of a datetime column in the Delta table whose values will be used to determine hot-cache eligibility. When set, data files whose rows have values within the configured Hot period (and/or HotWindows) are selected for caching. |
56+
5257
::: moniker-end
58+
5359
> [!NOTE]
54-
> 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](https://github.com/delta-io/delta/blob/master/PROTOCOL.md#add-file-and-remove-file).
60+
>
61+
> Query acceleration is applied to data within a specific time period, based on the `modificationTime` as stated for each file in the [delta log](https://github.com/delta-io/delta/blob/master/PROTOCOL.md#add-file-and-remove-file) by default. You can override the default behavior, by specifying the _HotDateTimeColumn_ property in the policy.
5562
5663
### Example
5764

@@ -72,17 +79,23 @@ The command returns a table with one record that includes the modified policy ob
7279
| EntityType | `string` | The type of the entity the policy applies to - `ExternalTable` |
7380

7481
## Example
82+
7583
::: moniker range="microsoft-fabric"
84+
7685
```Kusto
7786
.alter external table MyExternalTable policy query_acceleration '{"IsEnabled": true, "Hot": "1.00:00:00", "HotWindows":[{"MinValue":"2025-07-07 07:00:00","MaxValue":"2025-07-09 07:00:00"}], "MaxAge": "00:05:00", "HotDateTimeColumn":"dt1"}'
7887
```
88+
7989
::: moniker-end
8090

8191
::: moniker range="azure-data-explorer"
92+
8293
```Kusto
8394
.alter external table MyExternalTable policy query_acceleration '{"IsEnabled": true, "Hot": "1.00:00:00", "HotWindows":[{"MinValue":"2025-07-07 07:00:00","MaxValue":"2025-07-09 07:00:00"}], "MaxAge": "00:05:00", "ManagedIdentity": "12345678-1234-1234-1234-1234567890ab", "HotDateTimeColumn":"dt1"}'
8495
```
96+
8597
::: moniker-end
98+
8699
## Related content
87100

88101
- [Query acceleration policy](query-acceleration-policy.md)

0 commit comments

Comments
 (0)