Function rollupDay

telemetry-worker/src/rollup.ts:203–223

(
  env: Env,
  day: string,
  opts: { cutoff: string; reset?: boolean },
)

 * real day is the one irreversible thing this file could do.
 */
export async function rollupDay(
  env: Env,
  day: string,
  opts: { cutoff: string; reset?: boolean },
): Promise<DayResult> {
  const pastRetention = day < opts.cutoff;
  const statements: D1PreparedStatement[] = [];

  if (opts.reset && !pastRetention) {
    for (const table of EVENT_DERIVED_TABLES) {
      statements.push(env.DB.prepare(`DELETE FROM ${table} WHERE day = ?`).bind(day));
    }
  }
  for (const sql of ROLLUP_STATEMENTS) {
    statements.push(env.DB.prepare(sql).bind(day));
  }

  const results = await env.DB.batch(statements);
  const rows = results.reduce((total, r) => total + (r.meta?.changes ?? 0), 0);
  return { day, rows, pastRetention };
}

export interface PurgeResult {
  /** Everything strictly before this day was deleted. */