Prefer options

The API supports setting some request and response options using the Prefer header. This section describes how to set each preference and their values.

In the query language, you can specify different render options. By default, the API doesn't return information about the type of visualization. To include a specific visualization, include this header:

    Prefer: include-render=true

The header includes a render property in the response that specifies the type of visualization selected by the query and any properties for that visualization.

For example, the following request specifies a visualization of a bar chart with title "Perf events in the last day":

    POST https://api.loganalytics.azure.cn/v1/workspaces/{workspace-id}/query
    Authorization: Bearer <access token>
    Prefer: include-render=true
    Content-Type: application/json
    
    {
        "query": "Perf | summarize count() by bin(TimeGenerated, 4h) | render barchart title='24H Perf events'",
        "timespan": "P1D"
    }

The response contains a render property, which describes the metadata for the selected visualization.

    HTTP/1.1 200 OK
    Content-Type: application/json; charset=utf-8
    
    {
        "tables": [ ...query results... ],
        "render": {
            "visualization": "barchart",
            "title": "24H Perf events",
            "accumulate": false,
            "isQuerySorted": false,
            "kind": "default",
            "annotation": "",
            "by": null
        }
    }

To get information about query statistics, include this header:

    Prefer: include-statistics=true

The header includes a statistics property in the response that describes various performance statistics such as query execution time and resource usage.

The default query timeout is 3 minutes. To adjust the query timeout set the wait property, as documented here.

To get information about the query data sources - regions, workspaces, clusters and tables, include this header:

    Prefer: include-dataSources=true