ALTER TABLE digital_human_jobs
    ADD COLUMN IF NOT EXISTS checkpoint_fingerprint VARCHAR(64) NOT NULL DEFAULT '',
    ADD COLUMN IF NOT EXISTS checkpoint JSON;

CREATE INDEX IF NOT EXISTS idx_digital_human_retry_checkpoint
    ON digital_human_jobs (tenant_id, owner_id, digital_human_id, checkpoint_fingerprint, updated_at DESC)
    WHERE status = 'failed' AND checkpoint IS NOT NULL;