flattenPB,
parentRowType,
childRowType,
LEFT_JOIN,
KEEP_PARENT);
RowType pbRowType = flattenPB.rowType();
checkRowFields(pbRowType);
RowType pcRowType = plan.rowType();
checkRowFields(pcRowType);
Row[] expected = new Row[]{
row(ancestorRowType, 4L, "a4"),
row(parentRowType, 41L, 4L, "p41"),
row(pbRowType, 41L, 4L, "p41", null, null, null),