ALTER TABLE memory_subjects ADD COLUMN session_cursors JSON;
ALTER TABLE memory_subjects ADD COLUMN extract_attempt_id VARCHAR(36) NOT NULL DEFAULT '';
ALTER TABLE memory_subjects ADD COLUMN extract_lease_until DATETIME;
ALTER TABLE memory_subjects ADD COLUMN extract_started_at DATETIME;
ALTER TABLE memory_subjects ADD COLUMN extract_next_at DATETIME;
ALTER TABLE memory_subjects ADD COLUMN extract_failures INTEGER NOT NULL DEFAULT 0;
ALTER TABLE memory_subjects ADD COLUMN extract_chat_model_id VARCHAR(64) NOT NULL DEFAULT '';
ALTER TABLE memory_subjects ADD COLUMN extract_language VARCHAR(64) NOT NULL DEFAULT '';
CREATE INDEX idx_memory_extraction_due ON memory_subjects(extract_next_at);