diff --git a/src/cuda_common.h b/src/cuda_common.h
index 8306b7937..c15511af6 100644
--- a/src/cuda_common.h
+++ b/src/cuda_common.h
@@ -43,8 +43,6 @@ STROM_WRITEBACK_ERROR_STATUS(kern_errorbuf *ebuf, kern_context *kcxt)
 				  ERRCODE_STROM_SUCCESS,
 				  kcxt->errcode) == ERRCODE_STROM_SUCCESS)
 	{
-		const char *filename = __basenam
-
 		ebuf->errcode = kcxt->errcode;
 		ebuf->lineno  = kcxt->error_lineno;
 		__strncpy(ebuf->filename,
diff --git a/src/misc.c b/src/misc.c
index 32bc68760..9410108a6 100644
--- a/src/misc.c
+++ b/src/misc.c
@@ -18,64 +18,80 @@
  *
  * ----------------------------------------------------------------
  */
-static List *
-__form_codegen_kvar_defitem(codegen_kvar_defitem *kvdef)
+static void
+__form_codegen_kvar_defitem(codegen_kvar_defitem *kvdef,
+							List **p__kv_privs,
+							List **p__kv_exprs)
 {
-	List	   *result = NIL;
-	List	   *subfields = NIL;
+	List	   *__kv_privs = NIL;
+	List	   *__kv_exprs = NIL;
+	List	   *__sub_privs = NIL;
+	List	   *__sub_exprs = NIL;
 	ListCell   *lc;
 
-	result = lappend(result, makeInteger(kvdef->kv_slot_id));
-	result = lappend(result, makeInteger(kvdef->kv_depth));
-	result = lappend(result, makeInteger(kvdef->kv_resno));
-	result = lappend(result, makeInteger(kvdef->kv_maxref));
-	result = lappend(result, makeInteger(kvdef->kv_offset));
-
-	result = lappend(result, makeInteger(kvdef->kv_type_oid));
-	result = lappend(result, makeInteger(kvdef->kv_type_code));
-	result = lappend(result, makeBoolean(kvdef->kv_typbyval));
-	result = lappend(result, makeInteger(kvdef->kv_typalign));
-	result = lappend(result, makeInteger(kvdef->kv_typlen));
-	result = lappend(result, makeInteger(kvdef->kv_kvec_sizeof));
-	result = lappend(result, kvdef->kv_expr);
+	__kv_privs = lappend(__kv_privs, makeInteger(kvdef->kv_slot_id));
+	__kv_privs = lappend(__kv_privs, makeInteger(kvdef->kv_depth));
+	__kv_privs = lappend(__kv_privs, makeInteger(kvdef->kv_resno));
+	__kv_privs = lappend(__kv_privs, makeInteger(kvdef->kv_maxref));
+	__kv_privs = lappend(__kv_privs, makeInteger(kvdef->kv_offset));
+
+	__kv_privs = lappend(__kv_privs, makeInteger(kvdef->kv_type_oid));
+	__kv_privs = lappend(__kv_privs, makeInteger(kvdef->kv_type_code));
+	__kv_privs = lappend(__kv_privs, makeBoolean(kvdef->kv_typbyval));
+	__kv_privs = lappend(__kv_privs, makeInteger(kvdef->kv_typalign));
+	__kv_privs = lappend(__kv_privs, makeInteger(kvdef->kv_typlen));
+	__kv_privs = lappend(__kv_privs, makeInteger(kvdef->kv_kvec_sizeof));
+	__kv_exprs = lappend(__kv_exprs, kvdef->kv_expr);
 	foreach (lc, kvdef->kv_subfields)
 	{
 		codegen_kvar_defitem *__kvdef = lfirst(lc);
-		subfields = lappend(subfields, __form_codegen_kvar_defitem(__kvdef));
+		List   *__privs = NIL;
+		List   *__exprs = NIL;
+
+		__form_codegen_kvar_defitem(__kvdef, &__privs, &__exprs);
+		__sub_privs = lappend(__sub_privs, __privs);
+		__sub_exprs = lappend(__sub_exprs, __exprs);
 	}
-	result = lappend(result, subfields);
+	__kv_privs = lappend(__kv_privs, __sub_privs);
+	__kv_exprs = lappend(__kv_exprs, __sub_exprs);
 
-	return result;
+	*p__kv_privs = __kv_privs;
+	*p__kv_exprs = __kv_exprs;
 }
 
 static codegen_kvar_defitem *
-__deform_codegen_kvar_defitem(List *sublist)
+__deform_codegen_kvar_defitem(List *__kv_privs, List *__kv_exprs)
 {
 	codegen_kvar_defitem *kvdef = palloc0(sizeof(codegen_kvar_defitem));
-	List	   *subfields = NIL;
-	ListCell   *lc;
-	int			kvindex = 0;
-
-	kvdef->kv_slot_id  = intVal(list_nth(sublist, kvindex++));
-	kvdef->kv_depth    = intVal(list_nth(sublist, kvindex++));
-	kvdef->kv_resno    = intVal(list_nth(sublist, kvindex++));
-	kvdef->kv_maxref   = intVal(list_nth(sublist, kvindex++));
-	kvdef->kv_offset   = intVal(list_nth(sublist, kvindex++));
-
-	kvdef->kv_type_oid = intVal(list_nth(sublist, kvindex++));
-	kvdef->kv_type_code = intVal(list_nth(sublist, kvindex++));
-	kvdef->kv_typbyval = boolVal(list_nth(sublist, kvindex++));
-	kvdef->kv_typalign = intVal(list_nth(sublist, kvindex++));
-	kvdef->kv_typlen   = intVal(list_nth(sublist, kvindex++));
-	kvdef->kv_kvec_sizeof = intVal(list_nth(sublist, kvindex++));
-	kvdef->kv_expr     = list_nth(sublist, kvindex++);
-	subfields          = list_nth(sublist, kvindex++);
-	foreach (lc, subfields)
+	List	   *__sub_privs = NIL;
+	List	   *__sub_exprs = NIL;
+	ListCell   *lc1, *lc2;
+	int			pindex = 0;
+	int			eindex = 0;
+
+	kvdef->kv_slot_id   = intVal(list_nth(__kv_privs, pindex++));
+	kvdef->kv_depth     = intVal(list_nth(__kv_privs, pindex++));
+	kvdef->kv_resno     = intVal(list_nth(__kv_privs, pindex++));
+	kvdef->kv_maxref    = intVal(list_nth(__kv_privs, pindex++));
+	kvdef->kv_offset    = intVal(list_nth(__kv_privs, pindex++));
+
+	kvdef->kv_type_oid  = intVal(list_nth(__kv_privs, pindex++));
+	kvdef->kv_type_code = intVal(list_nth(__kv_privs, pindex++));
+	kvdef->kv_typbyval  = boolVal(list_nth(__kv_privs, pindex++));
+	kvdef->kv_typalign  = intVal(list_nth(__kv_privs, pindex++));
+	kvdef->kv_typlen    = intVal(list_nth(__kv_privs, pindex++));
+	kvdef->kv_kvec_sizeof = intVal(list_nth(__kv_privs, pindex++));
+	kvdef->kv_expr      = list_nth(__kv_exprs, eindex++);
+	__sub_privs         = list_nth(__kv_privs, pindex++);
+	__sub_exprs         = list_nth(__kv_exprs, eindex++);
+	forboth (lc1, __sub_privs,
+			 lc2, __sub_exprs)
 	{
-		List   *__sublist = lfirst(lc);
+		codegen_kvar_defitem *__kvdef;
 
-		kvdef->kv_subfields = lappend(kvdef->kv_subfields,
-									  __deform_codegen_kvar_defitem(__sublist));
+		__kvdef = __deform_codegen_kvar_defitem(lfirst(lc1),
+												lfirst(lc2));
+		kvdef->kv_subfields = lappend(kvdef->kv_subfields, __kvdef);
 	}
 	return kvdef;
 }
@@ -85,7 +101,8 @@ form_pgstrom_plan_info(CustomScan *cscan, pgstromPlanInfo *pp_info)
 {
 	List	   *privs = NIL;
 	List	   *exprs = NIL;
-	List	   *kvars_deflist = NIL;
+	List	   *kvars_deflist_privs = NIL;
+	List	   *kvars_deflist_exprs = NIL;
 	ListCell   *lc;
 	int			endpoint_id;
 
@@ -129,11 +146,16 @@ form_pgstrom_plan_info(CustomScan *cscan, pgstromPlanInfo *pp_info)
 	foreach (lc, pp_info->kvars_deflist)
 	{
 		codegen_kvar_defitem *kvdef = lfirst(lc);
+		List   *__kv_privs = NIL;
+		List   *__kv_exprs = NIL;
 
-		kvars_deflist = lappend(kvars_deflist, __form_codegen_kvar_defitem(kvdef));
+		__form_codegen_kvar_defitem(kvdef, &__kv_privs, &__kv_exprs);
+		kvars_deflist_privs = lappend(kvars_deflist_privs, __kv_privs);
+		kvars_deflist_exprs = lappend(kvars_deflist_exprs, __kv_exprs);
 	}
 	/* other planner fields */
-	privs = lappend(privs, kvars_deflist);
+	privs = lappend(privs, kvars_deflist_privs);
+	exprs = lappend(exprs, kvars_deflist_exprs);
 	privs = lappend(privs, makeInteger(pp_info->kvecs_bufsz));
 	privs = lappend(privs, makeInteger(pp_info->kvecs_ndims));
 	privs = lappend(privs, makeInteger(pp_info->extra_flags));
@@ -189,8 +211,9 @@ deform_pgstrom_plan_info(CustomScan *cscan)
 	List	   *exprs = cscan->custom_exprs;
 	int			pindex = 0;
 	int			eindex = 0;
-	List	   *kvars_deflist;
-	ListCell   *lc;
+	List	   *kvars_deflist_privs;
+	List	   *kvars_deflist_exprs;
+	ListCell   *lc1, *lc2;
 	int			endpoint_id;
 
 	memset(&pp_data, 0, sizeof(pgstromPlanInfo));
@@ -232,13 +255,17 @@ deform_pgstrom_plan_info(CustomScan *cscan)
 	pp_data.kexp_groupby_keycomp   = __getByteaConst(list_nth(privs, pindex++));
 	pp_data.kexp_groupby_actions   = __getByteaConst(list_nth(privs, pindex++));
 	/* Kvars definitions */
-	kvars_deflist = list_nth(privs, pindex++);
-	foreach (lc, kvars_deflist)
+	kvars_deflist_privs = list_nth(privs, pindex++);
+	kvars_deflist_exprs = list_nth(exprs, eindex++);
+	Assert(list_length(kvars_deflist_privs) == list_length(kvars_deflist_exprs));
+	forboth (lc1, kvars_deflist_privs,
+			 lc2, kvars_deflist_exprs)
 	{
-		List	   *sublist = (List *)lfirst(lc);
+		codegen_kvar_defitem *kvdef;
 
-		pp_data.kvars_deflist = lappend(pp_data.kvars_deflist,
-										__deform_codegen_kvar_defitem(sublist));
+		kvdef = __deform_codegen_kvar_defitem(lfirst(lc1),
+											  lfirst(lc2));
+		pp_data.kvars_deflist = lappend(pp_data.kvars_deflist, kvdef);
 	}
 	pp_data.kvecs_bufsz = intVal(list_nth(privs, pindex++));
 	pp_data.kvecs_ndims = intVal(list_nth(privs, pindex++));