CREATE UNLOGGED TABLE change_log (
    id BIGSERIAL PRIMARY KEY,
    table_name TEXT NOT NULL,
    row_id TEXT NOT NULL
);

ALTER TABLE change_log
SET (
        autovacuum_enabled = FALSE,
        toast.autovacuum_enabled = FALSE
    );

CREATE
OR REPLACE FUNCTION fn_process_change_log() RETURNS TRIGGER AS $$
DECLARE cur_state enum_switchover_state := 'idle';

BEGIN
SELECT INTO cur_state current_state
FROM switchover_state;

IF cur_state != 'in_progress' THEN RETURN NEW;

END IF;

IF (TG_OP = 'DELETE') THEN
INSERT INTO change_log (table_name, row_id)
VALUES (
        TG_TABLE_NAME,
        cast(OLD .id AS TEXT)
    );

RETURN OLD;

ELSE
INSERT INTO change_log (table_name, row_id)
VALUES (
        TG_TABLE_NAME,
        cast(NEW .id AS TEXT)
    );

RETURN NEW;

END IF;

RETURN NULL;

END;

$$ LANGUAGE 'plpgsql'