Mingle’s Daily History Chart works with historical data, and so can take a long time to prepare data. To speed up this process, Mingle uses a cache strategy.
How does daily history chart cache work?
The daily history chart is cached WHEN you go to the card or page containing a chart that has not already been cached.
Once the chart is cached, you should be able to quickly view the chart on the card or page containing the chart.
If you change values for any chart parameter, the existing cache should be cleared.
If you change meta data (e.g. modify/delete project variable, modify/delete card property), the existing cache should be cleared and new one will be generated.
Then why doesn't the daily history chart support the project parameter?
The project parameter allows you to access data from other Mingle projects to build cross project reports. Since the daily history chart uses cached data, it requires the cache to be cleared when the meta data of the source project is changed. Currently, Mingle does not have a mechanism to clear cache content for charts in other projects. That’s why we don’t support project parameter in daily history chart.