CREATE TABLE provider_dependency_state (
    tenant_id UUID NOT NULL REFERENCES tenant(id) ON DELETE CASCADE,
    provider VARCHAR(64) NOT NULL,
    status VARCHAR(16) NOT NULL DEFAULT 'AVAILABLE'
        CHECK (status IN ('AVAILABLE', 'UNAVAILABLE')),
    consecutive_failures INTEGER NOT NULL DEFAULT 0 CHECK (consecutive_failures >= 0),
    open_until TIMESTAMPTZ,
    last_error_code VARCHAR(64),
    last_failure_at TIMESTAMPTZ,
    last_success_at TIMESTAMPTZ,
    row_version BIGINT NOT NULL DEFAULT 1,
    updated_at TIMESTAMPTZ NOT NULL DEFAULT now(),
    PRIMARY KEY (tenant_id, provider)
);

CREATE INDEX idx_provider_dependency_unavailable
    ON provider_dependency_state (updated_at DESC)
    WHERE status = 'UNAVAILABLE';