diff --git a/include/groonga/plugin.h b/include/groonga/plugin.h
index c7f265bc83..94ed076710 100644
--- a/include/groonga/plugin.h
+++ b/include/groonga/plugin.h
@@ -151,6 +151,14 @@ void grn_plugin_mutex_lock(grn_ctx *ctx, grn_plugin_mutex *mutex);
  */
 void grn_plugin_mutex_unlock(grn_ctx *ctx, grn_plugin_mutex *mutex);
 
+/*
+  grn_plugin_proc_alloc() allocates a `grn_obj` object.
+  You can use it in function that is registered as GRN_PROC_FUNCTION.
+ */
+grn_obj *grn_plugin_proc_alloc(grn_ctx *ctx, grn_user_data *user_data,
+                               grn_id domain, grn_obj_flags flags);
+
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/plugin.c b/lib/plugin.c
index a91a709ab5..20da194ede 100644
--- a/lib/plugin.c
+++ b/lib/plugin.c
@@ -523,3 +523,10 @@ grn_plugin_mutex_unlock(grn_ctx *ctx, grn_plugin_mutex *mutex)
     CRITICAL_SECTION_LEAVE(mutex->critical_section);
   }
 }
+
+grn_obj *
+grn_plugin_proc_alloc(grn_ctx *ctx, grn_user_data *user_data,
+                      grn_id domain, grn_obj_flags flags)
+{
+  return grn_proc_alloc(ctx, user_data, domain, flags);
+}
diff --git a/plugins/query_expanders/tsv.c b/plugins/query_expanders/tsv.c
index ab75c5cadd..2e501a6469 100644
--- a/plugins/query_expanders/tsv.c
+++ b/plugins/query_expanders/tsv.c
@@ -20,8 +20,6 @@
 /* groonga's internal headers: They should be removed. */
 /* for grn_text_fgets() */
 #include <str.h>
-/* for GRN_PROC_ALLOC() */
-#include <db.h>
 /* for grn_win32_base_dir() */
 #include <util.h>
 
@@ -185,7 +183,7 @@ func_query_expander_tsv(grn_ctx *ctx, int nargs, grn_obj **args,
     rc = GRN_SUCCESS;
   }
 
-  rc_object = GRN_PROC_ALLOC(GRN_DB_INT32, 0);
+  rc_object = grn_plugin_proc_alloc(ctx, user_data, GRN_DB_INT32, 0);
   if (rc_object) {
     GRN_INT32_SET(ctx, rc_object, rc);
   }