Aliases, relations, and lazy evaluation
Wednesday, February 23, 2011
10:43 AM
Aliases, relations, and lazy evaluation
To make things as efficient as possible, Pig computes the results of an expression as late as possible. 
This is called lazy evaluation. 
When you write a statement in Pig, it is not executed immediately, but instead, recorded as something to be executed later. 
Thus, all variables in Pig are actually aliases for instructions to be executed later. 