protected void addPartitionColsToInsert(List<FieldSchema> partCols, StringBuilder rewrittenQueryStr) {
    addPartitionColsToInsert(partCols, null, rewrittenQueryStr);
  }
Append list of partition columns to Insert statement, i.e. the 1st set of partCol1,partCol2
INSERT INTO T PARTITION(partCol1,partCol2...) SELECT col1, ... partCol1,partCol2...
ql/src/java/org/apache/hadoop/hive/ql/parse/SemanticAnalyzer.java