flowchart TD Src["lrs.statements
one row per statement"]:::src MV1["mv_section_concept_daily
grain: section + concept + day"]:::p1 MV2["mv_student_concept_rollup
grain: student + concept"]:::p2 MV3["mv_student_page_rollup
grain: student + page"]:::p3 Sum["Summarizer
reads changed rows via last_seen watermark"]:::src V1["SectionRollup vertex"]:::p1 V2["ConceptMastery vertex"]:::p2 V3["PageEngagement vertex"]:::p3 Src --> MV1 --> Sum Src --> MV2 --> Sum Src --> MV3 --> Sum Sum --> V1 Sum --> V2 Sum --> V3 classDef src fill:#5f6e82,stroke:#3f4a59,color:#fff,font-size:13px classDef p1 fill:#0f5c53,stroke:#0a3f39,color:#fff,font-size:13px classDef p2 fill:#2a9d8f,stroke:#1f7a6f,color:#fff,font-size:13px classDef p3 fill:#8fd3c9,stroke:#3bab9d,color:#0c2f2b,font-size:13px linkStyle default stroke:#999,stroke-width:2px