-- One row per Series that is failing right now (ADR-0016): the row's
-- existence is the failure state, failing_since ages the run of failures,
-- and a correct read deletes the row. Keyed by the same (site, series_id)
-- composite the rest of the system uses, with the cascade so deleting a
-- Series takes its failure row and orphan removal stays a single statement.
CREATE TABLE poll_failures (
	site text NOT NULL,
	series_id text NOT NULL,
	outcome text NOT NULL,
	failing_since bigint NOT NULL,
	PRIMARY KEY (site, series_id),
	FOREIGN KEY (site, series_id) REFERENCES series (site, series_id) ON DELETE CASCADE
);