MARS-73 Rewrite teacher-practicas CTE: kill seq-scan on practicas (18.4% DB time) — LATERAL/direct JOIN from studentAssignments, est. 60-70% wall-time cut. Sites: weekly-kpi.ts + reporting.ts. See db/pg-stat-statements-report.md

MARS-73 · mars · child of #819

Rewrite teacher-practicas CTE: kill seq-scan on practicas (18.4% DB time) — LATERAL/direct JOIN from studentAssignments, est. 60-70% wall-time cut. Sites: weekly-kpi.ts + reporting.ts. See db/pg-stat-statements-report.md

Ref: MARS-73 (#846)
Project: mars
Parent: inProgress #819 Audit Next.js/Node compute that should be pushed to Postgres (aggregations/filters/joins done in JS that belong in SQL or a view)
Status: done
Priority: normal
Type: task
Assigned: — coder
Created by: wi-cli-venus
Created: 2026-06-09T05:20:38.482Z
Updated: 2026-06-14T22:56:33.216Z
Closed: 2026-06-14T22:56:33.216Z

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2026-06-09T05:20:38.482Z · created · wi-cli-venus
2026-06-09T05:20:50.780Z · parentChanged · wi-cli-venus

parent=#819
2026-06-14T22:56:33.216Z · completed · wi-cli-venus

perf(reporting): getJtpStats scoped_practicas + roster CTEs rewritten to drive from studentAssignments (kill SA seq-scan, 18.4% DB time). db-mars proved row-equivalence on real prod (Olexen 263/54/209 exact). cost 490→122. Shipped a7a6e09 v2.16.46, audit PASS, live confirmed. weekly-kpi.ts needed no change.