diff --git a/doc/src/sgml/fdwhandler.sgml b/doc/src/sgml/fdwhandler.sgml
index dc2d890..66210d5 100644
--- a/doc/src/sgml/fdwhandler.sgml
+++ b/doc/src/sgml/fdwhandler.sgml
@@ -1022,6 +1022,20 @@ GetForeignTable(Oid relid);
 
     <para>
 <programlisting>
+UserMapping *
+GetUserMappingById(Oid umid);
+</programlisting>
+
+     This function returns a <structname>UserMapping</structname> object for
+     the given user mapping OID.  The OID of a user mapping is available in
+     <structname>RelOptInfo</structname> for a foreign scan.
+     (If there is no mapping for the OID, it will throw an error.)
+     A <structname>UserMapping</structname> object contains properties of the
+     user mapping (see <filename>foreign/foreign.h</filename> for details).
+    </para>
+
+    <para>
+<programlisting>
 List *
 GetForeignColumnOptions(Oid relid, AttrNumber attnum);
 </programlisting>
diff --git a/src/backend/foreign/foreign.c b/src/backend/foreign/foreign.c
index 47c00af..18e1418 100644
--- a/src/backend/foreign/foreign.c
+++ b/src/backend/foreign/foreign.c
@@ -160,6 +160,54 @@ GetForeignServerByName(const char *srvname, bool missing_ok)
 	return GetForeignServer(serverid);
 }
 
+/*
+ * GetUserMappingById - look up the user mapping by its OID.
+ */
+UserMapping *
+GetUserMappingById(Oid umid)
+{
+	Datum		datum;
+	HeapTuple	tp;
+	bool		isnull;
+	UserMapping *um;
+
+	tp = SearchSysCache1(USERMAPPINGOID, ObjectIdGetDatum(umid));
+	if (!HeapTupleIsValid(tp))
+		elog(ERROR, "cache lookup failed for user mapping %u", umid);
+
+	um = (UserMapping *) palloc(sizeof(UserMapping));
+	um->umid = umid;
+
+	/* Extract the umuser */
+	datum = SysCacheGetAttr(USERMAPPINGOID,
+							tp,
+							Anum_pg_user_mapping_umuser,
+							&isnull);
+	Assert(!isnull);
+	um->userid = DatumGetObjectId(datum);
+
+	/* Extract the umserver */
+	datum = SysCacheGetAttr(USERMAPPINGOID,
+							tp,
+							Anum_pg_user_mapping_umserver,
+							&isnull);
+	Assert(!isnull);
+	um->serverid = DatumGetObjectId(datum);
+
+	/* Extract the umoptions */
+	datum = SysCacheGetAttr(USERMAPPINGOID,
+							tp,
+							Anum_pg_user_mapping_umoptions,
+							&isnull);
+	if (isnull)
+		um->options = NIL;
+	else
+		um->options = untransformRelOptions(datum);
+
+	ReleaseSysCache(tp);
+
+	return um;
+}
 
 /*
  * GetUserMapping - look up the user mapping.
diff --git a/src/include/foreign/foreign.h b/src/include/foreign/foreign.h
index d135916..71f8e55 100644
--- a/src/include/foreign/foreign.h
+++ b/src/include/foreign/foreign.h
@@ -73,6 +73,7 @@ extern ForeignServer *GetForeignServer(Oid serverid);
 extern ForeignServer *GetForeignServerByName(const char *name, bool missing_ok);
 extern UserMapping *GetUserMapping(Oid userid, Oid serverid);
 extern Oid GetUserMappingId(Oid userid, Oid serverid);
+extern UserMapping *GetUserMappingById(Oid umid);
 extern ForeignDataWrapper *GetForeignDataWrapper(Oid fdwid);
 extern ForeignDataWrapper *GetForeignDataWrapperByName(const char *name,
 							bool missing_ok);