Etsuro Fujita, slightly adjusted by me.
Discussion: http://postgr.es/m/
e87c4a6d-23d7-5e7c-e8db-
44ed418eb5d1@lab.ntt.co.jp
* 'operation' is the operation type
* 'canSetTag' is true if we set the command tag/es_processed
* 'nominalRelation' is the parent RT index for use of EXPLAIN
+ * 'partitioned_rels' is an integer list of RT indexes of non-leaf tables in
+ * the partition tree, if this is an UPDATE/DELETE to a partitioned table.
+ * Otherwise NIL.
* 'resultRelations' is an integer list of actual RT indexes of target rel(s)
* 'subpaths' is a list of Path(s) producing source data (one per rel)
* 'subroots' is a list of PlannerInfo structs (one per rel)