--> Explain types of re-distribution of data happening for joining of columns from two tables Case 1 - P.I = P.I joins Case 2 - P.I = non Index joins Case 3 - non Index = non Index joins

Case1 - there is no redistribution of data over amp's. Since amp local joins happen as data are present in same AMP and need not be re-distributed. These types of joins on unique primary index are very fast.
Case2 - data from second table will be re-distributed on all amps since joins are happening on PI vs. non Index column. Ideal scenario is when small table is redistributed to be joined with large table records on same amp
case3 - data from both the tables are redistributed on all AMPs. This is one of the longest processing queries , Care should be taken to see that stats are collected on these columns 
How to skip the header row in the fastload script

RECORD 2; /* this skips first record in the source file */
DEFINE ...