We radically improved the burndown chart performance. Now most burndowns will be nearly instantaneous!
Just to give you some numbers: burndown for a week-long sprint with 5 users and 50 tasks is rendered 5 times faster! Previously it took 300ms, now - only 60ms.
Corporate and Enterprise users should benefit from this optimization the most. Burndowns on ad-hoc analytics pages were unusably slow. Now they will usually take less than a second to calculate and render. For example, multisprint burndown for last two sprints in our organization became 18 times faster! Before it took 11sec, now - only 0.6 sec.
Please note that we optimized only ad-hoc analytics burndowns. Rendering the list of tasks for multisprint analytics might still be slow. We'll speed that up later.
As an aside note, Acunote uses the burndown data to make predictions. Therefore predictions became proportionally faster too!