Octave is a Plotly Dash application used daily by about 1,000 Hydro-Québec technicians and engineers to analyze smart meter load and voltage data from 4.5M meters across the province. As adoption grew, Octave’s back end was migrated to Databricks to address increasingly massive scale (>1T data points), governance and security requirements. This talk will summarize how Databricks was optimized to support performant at-scale interactive Dash application experiences while in parallel managing complex back-end ETL processes. The talk will outline optimizations targeted to further optimize query latency and user concurrency, along with plans to increase data update frequency. Non-technology related success factors to be reviewed will include the value of: subject matter expertise, operational autonomy, code quality for long-term maintainability and proactive vendor technical support.