  Supporting the interactive exploration of large datasets is a popular and
challenging use case for data management systems. Traditionally, the interface
and the back-end system are built and optimized separately, and interface
design and system optimization require different skill sets that are difficult
for one person to master. To enable analysts to focus on visualization design,
we contribute VegaPlus, a system that automatically optimizes interactive
dashboards to support large datasets. To achieve this, VegaPlus leverages two
core ideas. First, we introduce an optimizer that can reason about execution
plans in Vega, a back-end DBMS, or a mix of both environments. The optimizer
also considers how user interactions may alter execution plan performance, and
can partially or fully rewrite the plans when needed. Through a series of
benchmark experiments on seven different dashboard designs, our results show
that VegaPlus provides superior performance and versatility compared to
standard dashboard optimization techniques.
