-- Per-phase timing breakdown for HTTP checks. Pre-existing rows leave
-- these NULL; the dashboard chart skips nulls. response_ms remains the
-- canonical total (alert email avg still reads it).
ALTER TABLE checks ADD COLUMN dns_ms  INTEGER;
ALTER TABLE checks ADD COLUMN tcp_ms  INTEGER;
ALTER TABLE checks ADD COLUMN tls_ms  INTEGER;
ALTER TABLE checks ADD COLUMN ttfb_ms INTEGER;
