[SOLVED] How to get log based yaxis scaling working with a columnchart in azure kql?

How to get log based yaxis scaling working with a columnchart in azure kql?

I have a query

CommonSecurityLog
| where DeviceVendor == 'Foo'
| where DeviceProduct startswith 'Thing'
| extend ReceivedMegaBytes = (ReceivedBytes / 1024.0 / 1024.0)
| extend SentMegaBytes = (SentBytes / 1024.0 / 1024.0)
| summarize
    ['ReceivedMegaBytes'] = sum(ReceivedMegaBytes)
 by
    ['Time Block'] = bin(MyFooTime, 10m)
| render columnchart  with ( title='traffic', kind=stacked, yaxis=log)

however, the rendering doesnt seem to change the columnchart yaxis to logarithmic scaling instead of linear?

is there something missing here?

Solution

The logarithmic scaling doesn't work in Log Analytics, only in Azure Data explorer.

Here are some AI generated data that shows proper logarithmic scaling in ADX, but not in Sentinel/LA - which I throw into both after fiddling with your query with my CommonSecurityLog data - the task left unaccomplished.

let SalesData = datatable(Timestamp: datetime, ProductCategory: string, SalesAmount: real)
[
    datetime(2025-10-01), "Electronics", 1500,
    datetime(2025-10-01), "Clothing", 700,
    datetime(2025-10-01), "Furniture", 300,
    datetime(2025-10-02), "Electronics", 2000,
    datetime(2025-10-02), "Clothing", 500,
    datetime(2025-10-02), "Furniture", 450,
    datetime(2025-10-03), "Electronics", 1700,
    datetime(2025-10-03), "Clothing", 900,
    datetime(2025-10-03), "Furniture", 300,
    datetime(2025-10-04), "Electronics", 2200,
    datetime(2025-10-04), "Clothing", 650,
    datetime(2025-10-04), "Furniture", 400,
    datetime(2025-10-05), "Electronics", 1800,
    datetime(2025-10-05), "Clothing", 800,
    datetime(2025-10-05), "Furniture", 350
];
SalesData
| summarize TotalSales = sum(SalesAmount) by bin(Timestamp, 1d), ProductCategory
| order by Timestamp asc
| render columnchart with (title="test", kind=stacked)