text: -- insert2.test
  -- 
  -- execsql {
  --       BEGIN;
  --       INSERT INTO t4 SELECT x+(SELECT max(x)+1 FROM t4),y FROM t4;
  --       SELECT count(*) from t4;
  --       ROLLBACK;
  -- }
  BEGIN;
  INSERT INTO t4 SELECT x+(SELECT max(x)+1 FROM t4),y FROM t4;
  SELECT count(*) from t4;
  ROLLBACK;