Please see this https://pig.apache.org/docs/r0.15.0/test.html#explai
Use the EXPLAIN operator to review the logical, physical, and map reduce execution plans that are used to compute the specified relationship.
If no script is given:
- The logical plan shows a pipeline of operators to be executed to build the relation. Type checking and backend-independent optimizations (such as applying filters early on) also apply.
- The physical plan shows how the logical operators are translated to backend-specific physical operators. Some backend optimizations also apply.
- The mapreduce plan shows how the physical operators are grouped into map reduce jobs.