3 files changed, 31 insertions, 28 deletions

diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 79d5e96021e..1590b643920 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -2803,27 +2803,34 @@ typedef struct HashState
 /* ----------------
  *	 SetOpState information
  *
- *		Even in "sorted" mode, SetOp nodes are more complex than a simple
- *		Unique, since we have to count how many duplicates to return.  But
- *		we also support hashing, so this is really more like a cut-down
- *		form of Agg.
+ *		SetOp nodes support either sorted or hashed de-duplication.
+ *		The sorted mode is a bit like MergeJoin, the hashed mode like Agg.
  * ----------------
  */
-/* this struct is private in nodeSetOp.c: */
-typedef struct SetOpStatePerGroupData *SetOpStatePerGroup;
+typedef struct SetOpStatePerInput
+{
+	TupleTableSlot *firstTupleSlot; /* first tuple of current group */
+	int64		numTuples;		/* number of tuples in current group */
+	TupleTableSlot *nextTupleSlot;	/* next input tuple, if already read */
+	bool		needGroup;		/* do we need to load a new group? */
+} SetOpStatePerInput;
 
 typedef struct SetOpState
 {
 	PlanState	ps;				/* its first field is NodeTag */
-	ExprState  *eqfunction;		/* equality comparator */
-	Oid		   *eqfuncoids;		/* per-grouping-field equality fns */
-	FmgrInfo   *hashfunctions;	/* per-grouping-field hash fns */
 	bool		setop_done;		/* indicates completion of output scan */
-	long		numOutput;		/* number of dups left to output */
+	int64		numOutput;		/* number of dups left to output */
+	int			numCols;		/* number of grouping columns */
+
 	/* these fields are used in SETOP_SORTED mode: */
-	SetOpStatePerGroup pergroup;	/* per-group working state */
-	HeapTuple	grp_firstTuple; /* copy of first tuple of current group */
+	SortSupport sortKeys;		/* per-grouping-field sort data */
+	SetOpStatePerInput leftInput;	/* current outer-relation input state */
+	SetOpStatePerInput rightInput;	/* current inner-relation input state */
+	bool		need_init;		/* have we read the first tuples yet? */
+
 	/* these fields are used in SETOP_HASHED mode: */
+	Oid		   *eqfuncoids;		/* per-grouping-field equality fns */
+	FmgrInfo   *hashfunctions;	/* per-grouping-field hash fns */
 	TupleHashTable hashtable;	/* hash table with one entry per group */
 	MemoryContext tableContext; /* memory context containing hash table */
 	bool		table_filled;	/* hash table filled yet? */
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index 0759e00e96d..58748d2ca6f 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -2342,13 +2342,12 @@ typedef struct WindowAggPath
 typedef struct SetOpPath
 {
 	Path		path;
-	Path	   *subpath;		/* path representing input source */
+	Path	   *leftpath;		/* paths representing input sources */
+	Path	   *rightpath;
 	SetOpCmd	cmd;			/* what to do, see nodes.h */
 	SetOpStrategy strategy;		/* how to do it, see nodes.h */
-	List	   *distinctList;	/* SortGroupClauses identifying target cols */
-	AttrNumber	flagColIdx;		/* where is the flag column, if any */
-	int			firstFlag;		/* flag value for first input relation */
-	Cardinality numGroups;		/* estimated number of groups in input */
+	List	   *groupList;		/* SortGroupClauses identifying target cols */
+	Cardinality numGroups;		/* estimated number of groups in left input */
 } SetOpPath;
 
 /*
diff --git a/src/include/nodes/plannodes.h b/src/include/nodes/plannodes.h
index 52f29bcdb69..4633121689c 100644
--- a/src/include/nodes/plannodes.h
+++ b/src/include/nodes/plannodes.h
@@ -1225,23 +1225,20 @@ typedef struct SetOp
 	/* how to do it, see nodes.h */
 	SetOpStrategy strategy;
 
-	/* number of columns to check for duplicate-ness */
+	/* number of columns to compare */
 	int			numCols;
 
 	/* their indexes in the target list */
-	AttrNumber *dupColIdx pg_node_attr(array_size(numCols));
+	AttrNumber *cmpColIdx pg_node_attr(array_size(numCols));
 
-	/* equality operators to compare with */
-	Oid		   *dupOperators pg_node_attr(array_size(numCols));
-	Oid		   *dupCollations pg_node_attr(array_size(numCols));
-
-	/* where is the flag column, if any */
-	AttrNumber	flagColIdx;
+	/* comparison operators (either equality operators or sort operators) */
+	Oid		   *cmpOperators pg_node_attr(array_size(numCols));
+	Oid		   *cmpCollations pg_node_attr(array_size(numCols));
 
-	/* flag value for first input relation */
-	int			firstFlag;
+	/* nulls-first flags if sorting, otherwise not interesting */
+	bool	   *cmpNullsFirst pg_node_attr(array_size(numCols));
 
-	/* estimated number of groups in input */
+	/* estimated number of groups in left input */
 	long		numGroups;
 } SetOp;