Add SQL Standard WITH ORDINALITY support for UNNEST (and any other SRF)

Author: Andrew Gierth, David Fetter
Reviewers: Dean Rasheed, Jeevan Chalke, Stephen Frost

3 files changed, 26 insertions, 7 deletions

diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 298af26e96..3b430e0f24 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1395,7 +1395,10 @@ typedef struct SubqueryScanState
  *		function appearing in FROM (typically a function returning set).
  *
  *		eflags				node's capability flags
- *		tupdesc				expected return tuple description
+ *		ordinal				column value for WITH ORDINALITY
+ *		scan_tupdesc		scan tuple descriptor 
+ *		func_tupdesc		function tuple descriptor 
+ *		func_slot			function result slot, or null
  *		tuplestorestate		private state of tuplestore.c
  *		funcexpr			state for function expression being evaluated
  * ----------------
@@ -1404,7 +1407,10 @@ typedef struct FunctionScanState
 {
 	ScanState	ss;				/* its first field is NodeTag */
 	int			eflags;
-	TupleDesc	tupdesc;
+	int64       ordinal;
+	TupleDesc	scan_tupdesc;
+	TupleDesc	func_tupdesc;
+	TupleTableSlot *func_slot;
 	Tuplestorestate *tuplestorestate;
 	ExprState  *funcexpr;
 } FunctionScanState;
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index b4013e893d..51fef68ca3 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -471,6 +471,7 @@ typedef struct RangeFunction
 {
 	NodeTag		type;
 	bool		lateral;		/* does it have LATERAL prefix? */
+	bool		ordinality;		/* does it have WITH ORDINALITY suffix? */
 	Node	   *funccallnode;	/* untransformed function call tree */
 	Alias	   *alias;			/* table alias & optional column aliases */
 	List	   *coldeflist;		/* list of ColumnDef nodes to describe result
@@ -651,8 +652,13 @@ typedef struct XmlSerialize
  *	  dropped columns.	Note however that a stored rule may have nonempty
  *	  colnames for columns dropped since the rule was created (and for that
  *	  matter the colnames might be out of date due to column renamings).
+ *
  *	  The same comments apply to FUNCTION RTEs when the function's return type
- *	  is a named composite type.
+ *	  is a named composite type. In addition, for all return types, FUNCTION
+ *    RTEs with ORDINALITY must always have the last colname entry being the
+ *    one for the ordinal column; this is enforced when constructing the RTE.
+ *    Thus when ORDINALITY is used, there will be exactly one more colname
+ *    than would have been present otherwise.
  *
  *	  In JOIN RTEs, the colnames in both alias and eref are one-to-one with
  *	  joinaliasvars entries.  A JOIN RTE will omit columns of its inputs when
@@ -751,15 +757,21 @@ typedef struct RangeTblEntry
 	/*
 	 * Fields valid for a function RTE (else NULL):
 	 *
-	 * If the function returns RECORD, funccoltypes lists the column types
-	 * declared in the RTE's column type specification, funccoltypmods lists
-	 * their declared typmods, funccolcollations their collations.	Otherwise,
-	 * those fields are NIL.
+	 * If the function returns an otherwise-unspecified RECORD, funccoltypes
+	 * lists the column types declared in the RTE's column type specification,
+	 * funccoltypmods lists their declared typmods, funccolcollations their
+	 * collations.  Note that in this case, ORDINALITY is not permitted, so
+	 * there is no extra ordinal column to be allowed for.
+	 *
+     * Otherwise, those fields are NIL, and the result column types must be
+	 * derived from the funcexpr while treating the ordinal column, if
+	 * present, as a special case.  (see get_rte_attribute_*)
 	 */
 	Node	   *funcexpr;		/* expression tree for func call */
 	List	   *funccoltypes;	/* OID list of column type OIDs */
 	List	   *funccoltypmods; /* integer list of column typmods */
 	List	   *funccolcollations;		/* OID list of column collation OIDs */
+	bool		funcordinality;	/* is this called WITH ORDINALITY? */
 
 	/*
 	 * Fields valid for a values RTE (else NIL):
diff --git a/src/include/nodes/plannodes.h b/src/include/nodes/plannodes.h
index aa4f12cec5..44ea0b7752 100644
--- a/src/include/nodes/plannodes.h
+++ b/src/include/nodes/plannodes.h
@@ -425,6 +425,7 @@ typedef struct FunctionScan
 {
 	Scan		scan;
 	Node	   *funcexpr;		/* expression tree for func call */
+	bool        funcordinality; /* WITH ORDINALITY */
 	List	   *funccolnames;	/* output column names (string Value nodes) */
 	List	   *funccoltypes;	/* OID list of column type OIDs */
 	List	   *funccoltypmods; /* integer list of column typmods */