Parallel Query Tuning - Expert Oracle RAC Performance Diagnostics and Tuning - page 248

To further understand the parallel exaction architecture, we try to analyze the explain plan generated by
optimizer to execute the query in parallel:
EXPLAIN PLAN FOR SELECT n_name,
r_name,
p_name,
s_name,
SUM(ps_supplycost)
FROM region,
nation,
supplier,
partsupp,
part
WHERE ps_partkey = p_partkey
AND ps_suppkey = s_suppkey
AND s_nationkey = n_nationkey
AND n_regionkey = r_regionkey
GROUP BY n_name,
r_name,
p_name,
s_name;
Table 8-1 illustrates the various columns in the preceding output and column description.