title: Spark inner join API returns too many records
body: <p><a href="https://filebin.net/bqdbgcuuc6jbnbpy/annual-enterprise-survey-2018-financial-year-provisional-csv.csv?t=9mkxw7wu" rel="nofollow noreferrer">File link here</a> I have two same dataframes each has 27817 rows.Try to inner join these dataframes it returns 128954989 rows. </p>
  
  <p>dataframe1.join(dataframe2,"_c0").count
  res16: Long = 128954989 </p>
  
  <p>how to resolve this .</p>