question about join/lookup
Posted: Thu Nov 20, 2014 2:16 am
Hi dear friend,
would you please help to clarify the usage of join stage and lookup stage ?
I have below questions.
1, in join stage, is it necessary to sort both input links ? what will happen if we don't sort but just patition the input data by the keys?
2, sometimes the join stage and lookup stage can do the same time, in what condition should i use join stage, and when should i use lookup?
Thanks!![Embarassed :oops:](./images/smilies/icon_redface.gif)
would you please help to clarify the usage of join stage and lookup stage ?
I have below questions.
1, in join stage, is it necessary to sort both input links ? what will happen if we don't sort but just patition the input data by the keys?
2, sometimes the join stage and lookup stage can do the same time, in what condition should i use join stage, and when should i use lookup?
Thanks!
![Embarassed :oops:](./images/smilies/icon_redface.gif)