Fix problems related to RangeTblEntry members enrname and enrtuples.

Commit 18ce3a4ab22d2984f8540ab480979c851dae5338 failed to update
the comments in parsenodes.h for the new members, and made only
incomplete updates to src/backend/nodes

Thomas Munro, per a report from Noah Misch.

Discussion: http://postgr.es/m/20170611062525.GA1628882@rfd.leadboat.com

src/backend/nodes/copyfuncs.c

@@ -2303,10 +2303,11 @@ _copyRangeTblEntry(const RangeTblEntry *from)
 	COPY_STRING_FIELD(ctename);
 	COPY_SCALAR_FIELD(ctelevelsup);
 	COPY_SCALAR_FIELD(self_reference);
-	COPY_STRING_FIELD(enrname);
 	COPY_NODE_FIELD(coltypes);
 	COPY_NODE_FIELD(coltypmods);
 	COPY_NODE_FIELD(colcollations);
+	COPY_STRING_FIELD(enrname);
+	COPY_SCALAR_FIELD(enrtuples);
 	COPY_NODE_FIELD(alias);
 	COPY_NODE_FIELD(eref);
 	COPY_SCALAR_FIELD(lateral);

src/backend/nodes/equalfuncs.c

@@ -2631,6 +2631,8 @@ _equalRangeTblEntry(const RangeTblEntry *a, const RangeTblEntry *b)
 	COMPARE_NODE_FIELD(coltypes);
 	COMPARE_NODE_FIELD(coltypmods);
 	COMPARE_NODE_FIELD(colcollations);
+	COMPARE_STRING_FIELD(enrname);
+	COMPARE_SCALAR_FIELD(enrtuples);
 	COMPARE_NODE_FIELD(alias);
 	COMPARE_NODE_FIELD(eref);
 	COMPARE_SCALAR_FIELD(lateral);

src/backend/nodes/outfuncs.c

@@ -3047,6 +3047,7 @@ _outRangeTblEntry(StringInfo str, const RangeTblEntry *node)
 			break;
 		case RTE_NAMEDTUPLESTORE:
 			WRITE_STRING_FIELD(enrname);
+			WRITE_FLOAT_FIELD(enrtuples, "%.0f");
 			WRITE_OID_FIELD(relid);
 			WRITE_NODE_FIELD(coltypes);
 			WRITE_NODE_FIELD(coltypmods);

src/backend/nodes/readfuncs.c

@@ -1358,6 +1358,7 @@ _readRangeTblEntry(void)
 			break;
 		case RTE_NAMEDTUPLESTORE:
 			READ_STRING_FIELD(enrname);
+			READ_FLOAT_FIELD(enrtuples);
 			READ_OID_FIELD(relid);
 			READ_NODE_FIELD(coltypes);
 			READ_NODE_FIELD(coltypmods);

src/include/nodes/parsenodes.h

@@ -944,6 +944,11 @@ typedef struct RangeTblEntry
 
 	/*
 	 * Fields valid for a plain relation RTE (else zero):
+	 *
+	 * As a special case, RTE_NAMEDTUPLESTORE can also set relid to indicate
+	 * that the tuple format of the tuplestore is the same as the referenced
+	 * relation.  This allows plans referencing AFTER trigger transition
+	 * tables to be invalidated if the underlying table is altered.
 	 */
 	Oid			relid;			/* OID of the relation */
 	char		relkind;		/* relation kind (see pg_class.relkind) */
@@ -1004,16 +1009,23 @@ typedef struct RangeTblEntry
 	bool		self_reference; /* is this a recursive self-reference? */
 
 	/*
-	 * Fields valid for values and CTE RTEs (else NIL):
+	 * Fields valid for table functions, values, CTE and ENR RTEs (else NIL):
 	 *
 	 * We need these for CTE RTEs so that the types of self-referential
 	 * columns are well-defined.  For VALUES RTEs, storing these explicitly
 	 * saves having to re-determine the info by scanning the values_lists.
+	 * For ENRs, we store the types explicitly here (we could get the
+	 * information from the catalogs if 'relid' was supplied, but we'd still
+	 * need these for TupleDesc-based ENRs, so we might as well always store
+	 * the type info here).
 	 */
 	List	   *coltypes;		/* OID list of column type OIDs */
 	List	   *coltypmods;		/* integer list of column typmods */
 	List	   *colcollations;	/* OID list of column collation OIDs */
 
+	/*
+	 * Fields valid for ENR RTEs (else NULL/zero):
+	 */
 	char	   *enrname;		/* name of ephemeral named relation */
 	double		enrtuples;		/* estimated or actual from caller */