Rolling 30-day Aggregate View

CREATE MATERIALIZED VIEW daily_views_30d AS
  SELECT
    date_trunc('day', viewed_at) AS day,
    module_id,
    count(*) AS views
  FROM module_views
  WHERE viewed_at >= now() - interval '30 days'
  GROUP BY 1, 2;

CREATE UNIQUE INDEX ON daily_views_30d (day, module_id);

-- Refresh with CONCURRENTLY (no lock)
REFRESH MATERIALIZED VIEW CONCURRENTLY daily_views_30d;