diff --git a/contrib/bloom/blutils.c b/contrib/bloom/blutils.c
index 06077af..cb0f5f9 100644
--- a/contrib/bloom/blutils.c
+++ b/contrib/bloom/blutils.c
@@ -109,7 +109,6 @@ blhandler(PG_FUNCTION_ARGS)
 	amroutine->amstrategies = BLOOM_NSTRATEGIES;
 	amroutine->amsupport = BLOOM_NPROC;
 	amroutine->amcanorder = false;
-	amroutine->amcanorderbyop = false;
 	amroutine->amcanbackward = false;
 	amroutine->amcanunique = false;
 	amroutine->amcanmulticol = true;
@@ -138,6 +137,7 @@ blhandler(PG_FUNCTION_ARGS)
 	amroutine->amendscan = blendscan;
 	amroutine->ammarkpos = NULL;
 	amroutine->amrestrpos = NULL;
+	amroutine->amcanorderbyop = NULL;
 
 	PG_RETURN_POINTER(amroutine);
 }
diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index 3fce672..e85e224 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -82,7 +82,6 @@ brinhandler(PG_FUNCTION_ARGS)
 	amroutine->amstrategies = 0;
 	amroutine->amsupport = BRIN_LAST_OPTIONAL_PROCNUM;
 	amroutine->amcanorder = false;
-	amroutine->amcanorderbyop = false;
 	amroutine->amcanbackward = false;
 	amroutine->amcanunique = false;
 	amroutine->amcanmulticol = true;
@@ -111,6 +110,7 @@ brinhandler(PG_FUNCTION_ARGS)
 	amroutine->amendscan = brinendscan;
 	amroutine->ammarkpos = NULL;
 	amroutine->amrestrpos = NULL;
+	amroutine->amcanorderbyop = NULL;
 
 	PG_RETURN_POINTER(amroutine);
 }
diff --git a/src/backend/access/gin/ginutil.c b/src/backend/access/gin/ginutil.c
index 3909638..c7ff0fd 100644
--- a/src/backend/access/gin/ginutil.c
+++ b/src/backend/access/gin/ginutil.c
@@ -39,7 +39,6 @@ ginhandler(PG_FUNCTION_ARGS)
 	amroutine->amstrategies = 0;
 	amroutine->amsupport = GINNProcs;
 	amroutine->amcanorder = false;
-	amroutine->amcanorderbyop = false;
 	amroutine->amcanbackward = false;
 	amroutine->amcanunique = false;
 	amroutine->amcanmulticol = true;
@@ -68,6 +67,7 @@ ginhandler(PG_FUNCTION_ARGS)
 	amroutine->amendscan = ginendscan;
 	amroutine->ammarkpos = NULL;
 	amroutine->amrestrpos = NULL;
+	amroutine->amcanorderbyop = NULL;
 
 	PG_RETURN_POINTER(amroutine);
 }
diff --git a/src/backend/access/gist/gist.c b/src/backend/access/gist/gist.c
index 4092a8b..504d9ee 100644
--- a/src/backend/access/gist/gist.c
+++ b/src/backend/access/gist/gist.c
@@ -59,7 +59,6 @@ gisthandler(PG_FUNCTION_ARGS)
 	amroutine->amstrategies = 0;
 	amroutine->amsupport = GISTNProcs;
 	amroutine->amcanorder = false;
-	amroutine->amcanorderbyop = true;
 	amroutine->amcanbackward = false;
 	amroutine->amcanunique = false;
 	amroutine->amcanmulticol = true;
@@ -88,6 +87,7 @@ gisthandler(PG_FUNCTION_ARGS)
 	amroutine->amendscan = gistendscan;
 	amroutine->ammarkpos = NULL;
 	amroutine->amrestrpos = NULL;
+	amroutine->amcanorderbyop = gistcanorderbyop;
 
 	PG_RETURN_POINTER(amroutine);
 }
diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c
index f92baed..159987e 100644
--- a/src/backend/access/gist/gistutil.c
+++ b/src/backend/access/gist/gistutil.c
@@ -19,6 +19,7 @@
 #include "access/htup_details.h"
 #include "access/reloptions.h"
 #include "catalog/pg_opclass.h"
+#include "optimizer/paths.h"
 #include "storage/indexfsm.h"
 #include "storage/lmgr.h"
 #include "utils/builtins.h"
@@ -964,3 +965,31 @@ gistGetFakeLSN(Relation rel)
 		return GetFakeLSNForUnloggedRel();
 	}
 }
+
+/* gistcanorderbyop() */
+Expr *
+gistcanorderbyop(IndexOptInfo *index, PathKey *pathkey, int pathkeyno,
+				 Expr *orderby_clause, int *indexcol_p)
+{
+	int		indexcol;
+
+	/*
+	 * We allow any column of the GiST index to match each pathkey;
+	 * they don't have to match left-to-right as you might expect.
+	 */
+
+	for (indexcol = 0; indexcol < index->ncolumns; indexcol++)
+	{
+		Expr	   *expr = match_clause_to_ordering_op(index,
+													   indexcol,
+													   orderby_clause,
+													   pathkey->pk_opfamily);
+		if (expr)
+		{
+			*indexcol_p = indexcol;
+			return expr;
+		}
+	}
+
+	return NULL;
+}
diff --git a/src/backend/access/hash/hash.c b/src/backend/access/hash/hash.c
index 0cbf6b0..8cdefac 100644
--- a/src/backend/access/hash/hash.c
+++ b/src/backend/access/hash/hash.c
@@ -56,7 +56,6 @@ hashhandler(PG_FUNCTION_ARGS)
 	amroutine->amstrategies = HTMaxStrategyNumber;
 	amroutine->amsupport = HASHNProcs;
 	amroutine->amcanorder = false;
-	amroutine->amcanorderbyop = false;
 	amroutine->amcanbackward = true;
 	amroutine->amcanunique = false;
 	amroutine->amcanmulticol = false;
@@ -85,6 +84,7 @@ hashhandler(PG_FUNCTION_ARGS)
 	amroutine->amendscan = hashendscan;
 	amroutine->ammarkpos = NULL;
 	amroutine->amrestrpos = NULL;
+	amroutine->amcanorderbyop = NULL;
 
 	PG_RETURN_POINTER(amroutine);
 }
diff --git a/src/backend/access/nbtree/nbtree.c b/src/backend/access/nbtree/nbtree.c
index c6eed63..9e4384a 100644
--- a/src/backend/access/nbtree/nbtree.c
+++ b/src/backend/access/nbtree/nbtree.c
@@ -88,7 +88,6 @@ bthandler(PG_FUNCTION_ARGS)
 	amroutine->amstrategies = BTMaxStrategyNumber;
 	amroutine->amsupport = BTNProcs;
 	amroutine->amcanorder = true;
-	amroutine->amcanorderbyop = false;
 	amroutine->amcanbackward = true;
 	amroutine->amcanunique = true;
 	amroutine->amcanmulticol = true;
@@ -117,6 +116,7 @@ bthandler(PG_FUNCTION_ARGS)
 	amroutine->amendscan = btendscan;
 	amroutine->ammarkpos = btmarkpos;
 	amroutine->amrestrpos = btrestrpos;
+	amroutine->amcanorderbyop = NULL;
 
 	PG_RETURN_POINTER(amroutine);
 }
diff --git a/src/backend/access/spgist/spgutils.c b/src/backend/access/spgist/spgutils.c
index b9e4940..f18b0bc 100644
--- a/src/backend/access/spgist/spgutils.c
+++ b/src/backend/access/spgist/spgutils.c
@@ -38,7 +38,6 @@ spghandler(PG_FUNCTION_ARGS)
 	amroutine->amstrategies = 0;
 	amroutine->amsupport = SPGISTNProc;
 	amroutine->amcanorder = false;
-	amroutine->amcanorderbyop = false;
 	amroutine->amcanbackward = false;
 	amroutine->amcanunique = false;
 	amroutine->amcanmulticol = false;
@@ -67,6 +66,7 @@ spghandler(PG_FUNCTION_ARGS)
 	amroutine->amendscan = spgendscan;
 	amroutine->ammarkpos = NULL;
 	amroutine->amrestrpos = NULL;
+	amroutine->amcanorderbyop = NULL;
 
 	PG_RETURN_POINTER(amroutine);
 }
diff --git a/src/backend/optimizer/path/indxpath.c b/src/backend/optimizer/path/indxpath.c
index 0a5c050..b9b4701 100644
--- a/src/backend/optimizer/path/indxpath.c
+++ b/src/backend/optimizer/path/indxpath.c
@@ -17,6 +17,7 @@
 
 #include <math.h>
 
+#include "access/amapi.h"
 #include "access/stratnum.h"
 #include "access/sysattr.h"
 #include "catalog/pg_am.h"
@@ -166,8 +167,6 @@ static bool match_rowcompare_to_indexcol(IndexOptInfo *index,
 static void match_pathkeys_to_index(IndexOptInfo *index, List *pathkeys,
 						List **orderby_clauses_p,
 						List **clause_columns_p);
-static Expr *match_clause_to_ordering_op(IndexOptInfo *index,
-							int indexcol, Expr *clause, Oid pk_opfamily);
 static bool ec_member_matches_indexcol(PlannerInfo *root, RelOptInfo *rel,
 						   EquivalenceClass *ec, EquivalenceMember *em,
 						   void *arg);
@@ -2473,12 +2472,15 @@ match_pathkeys_to_index(IndexOptInfo *index, List *pathkeys,
 	List	   *orderby_clauses = NIL;
 	List	   *clause_columns = NIL;
 	ListCell   *lc1;
+	int			pathkeyno = 1;
+	amcanorderbyop_function amcanorderbyop =
+			(amcanorderbyop_function) index->amcanorderbyop;
 
 	*orderby_clauses_p = NIL;	/* set default results */
 	*clause_columns_p = NIL;
 
-	/* Only indexes with the amcanorderbyop property are interesting here */
-	if (!index->amcanorderbyop)
+	/* Only indexes with the amcanorderbyop function are interesting here */
+	if (!amcanorderbyop)
 		return;
 
 	foreach(lc1, pathkeys)
@@ -2512,42 +2514,29 @@ match_pathkeys_to_index(IndexOptInfo *index, List *pathkeys,
 		foreach(lc2, pathkey->pk_eclass->ec_members)
 		{
 			EquivalenceMember *member = (EquivalenceMember *) lfirst(lc2);
+			Expr	   *expr;
 			int			indexcol;
 
 			/* No possibility of match if it references other relations */
 			if (!bms_equal(member->em_relids, index->rel->relids))
 				continue;
 
-			/*
-			 * We allow any column of the index to match each pathkey; they
-			 * don't have to match left-to-right as you might expect.  This is
-			 * correct for GiST, which is the sole existing AM supporting
-			 * amcanorderbyop.  We might need different logic in future for
-			 * other implementations.
-			 */
-			for (indexcol = 0; indexcol < index->ncolumns; indexcol++)
-			{
-				Expr	   *expr;
+			expr = amcanorderbyop(index, pathkey, pathkeyno, member->em_expr,
+								  &indexcol);
 
-				expr = match_clause_to_ordering_op(index,
-												   indexcol,
-												   member->em_expr,
-												   pathkey->pk_opfamily);
-				if (expr)
-				{
-					orderby_clauses = lappend(orderby_clauses, expr);
-					clause_columns = lappend_int(clause_columns, indexcol);
-					found = true;
-					break;
-				}
+			if (expr)
+			{
+				orderby_clauses = lappend(orderby_clauses, expr);
+				clause_columns = lappend_int(clause_columns, indexcol);
+				found = true;
+				break; /* don't want to look at remaining members */
 			}
-
-			if (found)			/* don't want to look at remaining members */
-				break;
 		}
 
 		if (!found)				/* fail if no match for this pathkey */
 			return;
+
+		pathkeyno++;
 	}
 
 	*orderby_clauses_p = orderby_clauses;		/* success! */
@@ -2579,7 +2568,7 @@ match_pathkeys_to_index(IndexOptInfo *index, List *pathkeys,
  * If successful, return 'clause' as-is if the indexkey is on the left,
  * otherwise a commuted copy of 'clause'.  If no match, return NULL.
  */
-static Expr *
+Expr *
 match_clause_to_ordering_op(IndexOptInfo *index,
 							int indexcol,
 							Expr *clause,
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index 7836e6b..93bda0f 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -237,7 +237,7 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
 
 			/* We copy just the fields we need, not all of rd_amroutine */
 			amroutine = indexRelation->rd_amroutine;
-			info->amcanorderbyop = amroutine->amcanorderbyop;
+			info->amcanorderbyop = (void (*)()) amroutine->amcanorderbyop;
 			info->amoptionalkey = amroutine->amoptionalkey;
 			info->amsearcharray = amroutine->amsearcharray;
 			info->amsearchnulls = amroutine->amsearchnulls;
diff --git a/src/include/access/amapi.h b/src/include/access/amapi.h
index 48b0cc0..436c5f8 100644
--- a/src/include/access/amapi.h
+++ b/src/include/access/amapi.h
@@ -21,6 +21,9 @@
  */
 struct PlannerInfo;
 struct IndexPath;
+struct IndexOptInfo;
+struct PathKey;
+struct Expr;
 
 /* Likewise, this file shouldn't depend on execnodes.h. */
 struct IndexInfo;
@@ -137,6 +140,12 @@ typedef void (*ammarkpos_function) (IndexScanDesc scan);
 /* restore marked scan position */
 typedef void (*amrestrpos_function) (IndexScanDesc scan);
 
+/* does AM support ORDER BY result of an operator on indexed column? */
+typedef struct Expr *(*amcanorderbyop_function) (struct IndexOptInfo *index,
+												 struct PathKey *pathkey,
+												 int pathkeyno,
+												 struct Expr *orderby_clause,
+												 int *indexcol_p);
 
 /*
  * API struct for an index AM.  Note this must be stored in a single palloc'd
@@ -155,8 +164,6 @@ typedef struct IndexAmRoutine
 	uint16		amsupport;
 	/* does AM support ORDER BY indexed column's value? */
 	bool		amcanorder;
-	/* does AM support ORDER BY result of an operator on indexed column? */
-	bool		amcanorderbyop;
 	/* does AM support backward scanning? */
 	bool		amcanbackward;
 	/* does AM support UNIQUE indexes? */
@@ -196,6 +203,7 @@ typedef struct IndexAmRoutine
 	amendscan_function amendscan;
 	ammarkpos_function ammarkpos;		/* can be NULL */
 	amrestrpos_function amrestrpos;		/* can be NULL */
+	amcanorderbyop_function amcanorderbyop; /* can be NULL */
 } IndexAmRoutine;
 
 
diff --git a/src/include/access/gist_private.h b/src/include/access/gist_private.h
index 72f52d4..0d35646 100644
--- a/src/include/access/gist_private.h
+++ b/src/include/access/gist_private.h
@@ -538,6 +538,11 @@ extern void gistMakeUnionKey(GISTSTATE *giststate, int attno,
 
 extern XLogRecPtr gistGetFakeLSN(Relation rel);
 
+extern struct Expr *gistcanorderbyop(struct IndexOptInfo *index,
+									 struct PathKey *pathkey,  int pathkeyno,
+									 struct Expr *orderby_clause,
+									 int *indexcol_p);
+
 /* gistvacuum.c */
 extern IndexBulkDeleteResult *gistbulkdelete(IndexVacuumInfo *info,
 			   IndexBulkDeleteResult *stats,
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h
index e1d31c7..ccf282a 100644
--- a/src/include/nodes/relation.h
+++ b/src/include/nodes/relation.h
@@ -616,7 +616,6 @@ typedef struct IndexOptInfo
 	bool		hypothetical;	/* true if index doesn't really exist */
 
 	/* Remaining fields are copied from the index AM's API struct: */
-	bool		amcanorderbyop; /* does AM support order by operator result? */
 	bool		amoptionalkey;	/* can query omit key for the first column? */
 	bool		amsearcharray;	/* can AM handle ScalarArrayOpExpr quals? */
 	bool		amsearchnulls;	/* can AM search for NULL/NOT NULL entries? */
@@ -624,6 +623,7 @@ typedef struct IndexOptInfo
 	bool		amhasgetbitmap; /* does AM have amgetbitmap interface? */
 	/* Rather than include amapi.h here, we declare amcostestimate like this */
 	void		(*amcostestimate) ();	/* AM's cost estimator */
+	void		(*amcanorderbyop) ();	/* does AM support order by operator result? */
 } IndexOptInfo;
 
 /*
diff --git a/src/include/optimizer/paths.h b/src/include/optimizer/paths.h
index 81a9be7..bb7611e 100644
--- a/src/include/optimizer/paths.h
+++ b/src/include/optimizer/paths.h
@@ -79,6 +79,10 @@ extern Expr *adjust_rowcompare_for_index(RowCompareExpr *clause,
 							int indexcol,
 							List **indexcolnos,
 							bool *var_on_left_p);
+extern Expr *match_clause_to_ordering_op(IndexOptInfo *index,
+							int indexcol,
+							Expr *clause,
+							Oid pk_opfamily);
 
 /*
  * tidpath.h