KQL Database consumption

KQL databases operate on a fully managed Kusto engine. With a KQL database, you can expect available compute for your analytics within 5 to 10 seconds. The compute resources grow with your data analytic needs. This article explains compute usage reporting of the KQL databases in Microsoft Fabric, including KustoUpTime and storage.

When you use a Fabric capacity, your usage charges appear in the Azure portal under your subscription in Microsoft Cost Management. To understand your Fabric billing, visit Understand your Azure bill on a Fabric capacity.

Important

Changes to Microsoft Fabric Workload Consumption Rate

Consumption rates are subject to change at any time. Microsoft will use reasonable efforts to provide notice via email or through in-product notification. Changes shall be effective on the date stated in Microsoft’s Release Notes or Microsoft Fabric Blog. If any change to a Microsoft Fabric Workload Consumption Rate materially increases the Capacity Units (CU) required to use a particular workload, customers can use the cancellation options available for the chosen payment method.

Capacity

Based on the Capacity SKU that was purchased in Fabric, you're entitled to a set of Capacity Units (CUs) that are shared across all Fabric workloads. For more information on licenses supported, see Microsoft Fabric licenses.

Capacity is a dedicated set of resources that is available at a given time to be used. Capacity defines the ability of a resource to perform an activity or to produce output. Different resources consume CUs at different times. The amount of capacity that used by a KQL database is based on the KustoUpTime operation.

KustoUpTime

KustoUpTime is the number of seconds that your KQL database is active in relation to the number of virtual cores used by your database. An autoscale mechanism is used to determine the size of your KQL database. This mechanism ensures cost and performance optimization based on your usage pattern.

For example, a database using 4 virtual cores that is active for 30 seconds will use 120 seconds of Capacity Units.

Monitor KustoUpTime

You can monitor KustoUpTime with the Microsoft Fabric Capacity Metric app. Learn how to understand the Metrics app compute page in Understand the metrics app compute page. This example shows information specific to monitoring KustoUpTime.

Note

You must be a capacity administrator to monitor capacity usage. For more information, see Understand Microsoft Fabric admin roles.

The following image shows a sample compute page from monitoring a KQL database in the Fabric Capacity Metric app:

Here are some insights you can take from the above example:

• The capacity being examined is called democapacity.
• The capacity units for the selected day were used by several different workspaces, such as Trident Real Time Analytics, Houston Event, and others.
• Selecting a single item, like the KQL database item on the top, breaks down the CU usage by operations.
• The utilization graph, on the right side of the app, shows nearly 100% CU usage over time. This high utilization explains query throttling experienced by the user and indicates a need to increase the capacity units.

Storage billing

Storage is billed separately from your Fabric or Power BI Premium Capacity units. Data ingested into a KQL database is stored in two tiers of storage: OneLake Cache Storage, and OneLake Standard Storage.

• OneLake Cache Storage is premium storage that is utilized to provide the fastest query response times. When you set the cache policy, you affect this storage tier. For instance, if you typically query back seven days then you can set the cache retention to seven days for best performance. This storage tier is comparable to the Azure ADLS (Azure Data Lake Storage) premium tier.

• OneLake Standard Storage is standard storage that is used to persist and store all queryable data. When you set the retention policy, you affect this storage tier. For instance, if you need to maintain 365 days of queryable data you can set the retention to 365 days. This storage tier is comparable to the Azure ADLS (Azure Data Lake Storage) hot tier.

Monitor OneLake Storage

The Microsoft Fabric Capacity Metric app allows any capacity administrator to monitor OneLake Storage. Learn how to understand the Metrics app storage page in Understand the metrics app storage page.

The following image shows a sample storage page from monitoring a KQL database in the Fabric Capacity Metric app:

Related content

• Microsoft Fabric concepts and licenses
• What is the Microsoft Fabric Capacity Metrics app?
• Create a KQL database