<literal>resultRelation</> identifies the target foreign table by its

rangetable index. <literal>subplan_index</> identifies which target of

the <structname>ModifyTable</> plan node this is, counting from zero;

use this if you want to index into <literal>node-&gt;plans</> or other

use this if you want to index into <literal>plan-&gt;plans</> or other

substructure of the <literal>plan</> node.

</para>