How to do left-outer join and right-outer join in a single read?

[Anonymous]

I have two input files. One is a main, the other is a look-up. Is there any way to do a left-outer join and a right-outer join without reading the input files twice?

[Anonymous]

Hi 
No, you have to do the join two times, and merge the two result, filter the duplicated rows. With a small data set, you can read the data only one time from the files and store them into memory first, read them from memory when doing join. eg:
tFileINputDelimited1--main--tHashOutput1
    |
tfileInputDelimited2--main--tHashOutput2
    |
onsubjobok
    |
tHashInput1--main--tMap--.....
                                |
                            lookup
                                |
                        tHashInput2

Best regards
Shong

[Anonymous]

Thanks for the quick reply!

However, I'm dealing with 5 million+ rows of data. Any best approach that you can suggest without compromising on the performace?

[Anonymous]

No other way can achieve it with best performance, you have to read the data two times.