insert overwrite doesn't throw exception when drop old data fails

dataframe.write.mode(SaveMode.Overwrite).insertInto(s"$databaseName.$tableName")

Insert overwrite mode will drop old data in hive table if there's old data.

But if data deleting fails, no exception will be thrown and the data folder will be like:

hdfs://uxs_nbp/nba_score/dt=2018-08-15/seq_num=2/part-00000

hdfs://uxs_nbp/nba_score/dt=2018-08-15/seq_num=2/part-000001534916642513.

Two copies of data will be kept.