Azure Application Insights KQL - How to accumulate values?

Question

I would like to accumulate values by timestamp in a ever growing manner.

The following query

ContainerLog
| extend logsize = string_size(LogEntry)
| summarize sum(logsize) by bin(TimeGenerated, 1m)
| render timechart 

generates a graph that goes up and down: I would like to add the previous value with the current value, this way generating an always growing graph symbolizing the total amount of requests up to that moment.

Answer 1

// Sample data generation. Not part of the solution.
let ContainerLog = materialize(range i from 1 to 15 step 1 | extend TimeGenerated = ago(7d*rand()), logsize = rand(1000));
// Solution starts here.
ContainerLog
| summarize sum(logsize) by bin(TimeGenerated, 1m)
| order by TimeGenerated asc
| extend accumulated_sum_logsize = row_cumsum(sum_logsize)
| render timechart

Fiddle

P.S.
I kept sum_logsize for learning purposes.
In your scenario it can be removed.