-- Per-MX-operator throttling for the trucking/main warmup pool.
-- Sender reputation is tracked by the RECEIVING mail operator (Microsoft 365,
-- Google Workspace, Proofpoint, ...), not by recipient domain. The Jun 13-14
-- Gmail + Outlook block storm came from hammering Google/MS-Workspace-hosted
-- business domains. mx_provider lets the builder exclude those during warmup and
-- cap volume per operator (mirrors the HC pool). Populated by mx_tag_carriers.py.

ALTER TABLE fmcsa_carriers
  ADD COLUMN IF NOT EXISTS mx_provider TEXT;

CREATE INDEX CONCURRENTLY IF NOT EXISTS idx_fmcsa_carriers_mx_provider
  ON fmcsa_carriers (mx_provider)
  WHERE mx_provider IS NOT NULL;