User Impact: Broken Dashboards with no data and only Templating Error to display
While verifying the performance for PMM-Server and UI response with server monitoring 1000 nodes & services, we observed an issue with changing scrape Frequency, causing many dashboards to show templating error.
A similar error could be easily observed on MySQL Table Details dashboard too, it can be easily seen on a PMM-Server intance monitoring roughly 100 mysql services
1) Monitor 1000 apprx. nodes & service with PMM
2) Change Scrape Interval from Standard to Frequent
3) Open Home Dashboard, Node Summary etc
4) You will see the error with a limit on matching time-series with the given time range, it seems we need to increase the default VM parameters.