What kind of Issues/bugs arise in ETL projects? I would like to know few issues (critical to somewhat bugs ) normally occur in ETL process especially when testing? Domains can be banking, healthcare or any.

1.To find faults in software
2.To purify that software has no defects.
3.To find perform problems.
4.To give cunt in software.

select best option.

How to check the existence of a lookup file in a graph ..The requriement is if Lookup file is present then some search will be carried out in the same else default value will be set. PLEASE NOTE we need to check the existence of the lookup file in graph level only..