SkewJoinOptimizer might not kick in if columns are renamed after TableScanOperator

set hive.optimize.skewjoin.compiletime = true;

CREATE TABLE T1(key STRING, val STRING)
SKEWED BY (key) ON ((2)) STORED AS TEXTFILE;

CREATE TABLE T2(key STRING, val STRING)
SKEWED BY (key) ON ((3)) STORED AS TEXTFILE;

SELECT a.*, b.*
FROM T1 a JOIN T2 b
ON a.key = b.key

SELECT a.*, b.*
FROM 
  (SELECT key as k, val as v FROM T1) a
  JOIN
  (SELECT key as k, val as v FROM T2) b
ON a.k = b.k;