G select * from t1 right join t2 on t1.f1 = t2.f2; (before rewrites) cluster0 Box0:Select cluster1 Box1:OuterJoin cluster3 Box3:BaseTable T2 cluster2 Box2:BaseTable T1 boxhead0 Distinct: Preserve 0: Q2.c0 as F1 1: Q2.c1 as F2 2: Q2.c2 as F3 3: Q2.c3 as F1 4: Q2.c4 as F2 5: Q2.c5 as F3 Q2 Q2(F) boxhead1 Distinct: Preserve 0: Q0.c0 as F1 1: Q0.c1 as F2 2: Q0.c2 as F3 3: Q1.c0 as F1 4: Q1.c1 as F2 5: Q1.c2 as F3 Q2->boxhead1 Q0 Q0(F) as T1 Q1 Q1(P) as T2 Q0->Q1 (Q0.c0) = (Q1.c1) boxhead2 Distinct: Preserve 0: c0 as F1 1: c1 as F2 2: c2 as F3 Q0->boxhead2 boxhead3 Distinct: Preserve 0: c0 as F1 1: c1 as F2 2: c2 as F3 Q1->boxhead3