this.joinComparator = new JoinTupleComparator(outer.getSchema(), inner.getSchema(), sortSpecs);
this.tupleComparator = PlannerUtil.getComparatorsFromJoinQual(
plan.getJoinQual(), outer.getSchema(), inner.getSchema());
// for projection
this.projector = new Projector(inSchema, outSchema, plan.getTargets());
this.evalContexts = projector.renew();
// for join
frameTuple = new FrameTuple();
outTuple = new VTuple(outSchema.getColumnNum());