Auto-Prep: Holistic Prediction of Data Preparation Steps for Self-Service Business Intelligence

Business Intelligence (BI) plays a critical role in empowering modern enterprises to make informed data-driven decisions, and has grown into a billion-dollar business. Self-service BI tools like Power BI and Tableau have democratized the ``dashboarding'' phase of BI, by offering user-friendly, drag-and-drop interfaces that are tailored to non-technical enterprise users. However, despite these advances, we observe that the ``data preparation'' phase of BI continues to be a key pain point for BI users today. In this work, we systematically study around 2K real BI projects harvested from public sources, focusing on the data-preparation phase of the BI workflows. We observe that users often have to program both (1) data transformation steps and (2) table joins steps, before their raw data can be ready for dashboarding and analysis. A careful study of the BI workflows reveals that transformation and join steps are often intertwined in the same BI project, such that considering both holistically is crucial to accurately predict these steps. Leveraging this observation, we develop an Auto-Prep system to holistically predict transformations and joins, using a principled graph-based algorithm inspired by Steiner-tree, with provable quality guarantees. Extensive evaluations using real BI projects suggest that Auto-Prep can correctly predict over 70\% transformation and join steps, significantly more accurate than existing algorithms as well as language-models such as GPT-4.