HAWQ-1811. set hawq_rm_stmt_vseg_memory to 256mb by default
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index a56a59c..cf98f22 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -8805,7 +8805,7 @@
 			NULL
 		},
 		&rm_stmt_vseg_mem_str,
-		"128mb", assign_hawq_rm_stmt_vseg_memory, NULL
+		"256mb", assign_hawq_rm_stmt_vseg_memory, NULL
 	},
 
 	{