MDEV-7098 spider/bg.spider_fixes failed in buildbot with safe_mutex: Trying to unlock mutex conn->mta_conn_mutex that wasn't locked at storage/spider/spd_db_conn.cc, line 671bb-10.4-midenok-MDEV-18706

8 files changed, 1658 insertions, 545 deletions

diff --git a/storage/spider/ha_spider.cc b/storage/spider/ha_spider.cc
index 1f4439161b2..b2600859b88 100644
--- a/storage/spider/ha_spider.cc
+++ b/storage/spider/ha_spider.cc
@@ -2333,6 +2333,7 @@ int ha_spider::index_read_map_internal(
       }
 #endif
       spider_db_handler *dbton_hdl = dbton_handler[conn->dbton_id];
+      pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
       if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
       {
         pthread_mutex_lock(&conn->mta_conn_mutex);
@@ -2340,6 +2341,11 @@ int ha_spider::index_read_map_internal(
       }
       if ((error_num = dbton_hdl->set_sql_for_exec(sql_type, roop_count)))
       {
+        if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
+        {
+          SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+          pthread_mutex_unlock(&conn->mta_conn_mutex);
+        }
         DBUG_RETURN(error_num);
       }
       if (!dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
@@ -2361,11 +2367,15 @@ int ha_spider::index_read_map_internal(
       } else {
 #endif
         conn->need_mon = &need_mons[roop_count];
+        DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = TRUE;
         conn->mta_conn_mutex_unlock_later = TRUE;
         if ((error_num = spider_db_set_names(this, conn,
           roop_count)))
         {
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -2401,6 +2411,8 @@ int ha_spider::index_read_map_internal(
           result_list.quick_mode,
           &need_mons[roop_count])
         ) {
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           error_num = spider_db_errorno(conn);
@@ -2428,6 +2440,8 @@ int ha_spider::index_read_map_internal(
           DBUG_RETURN(check_error_mode_eof(error_num));
         }
         connection_ids[roop_count] = conn->connection_id;
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         if (roop_count == link_ok)
@@ -2829,6 +2843,7 @@ int ha_spider::index_read_last_map_internal(
       }
 #endif
       spider_db_handler *dbton_hdl = dbton_handler[conn->dbton_id];
+      pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
       if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
       {
         pthread_mutex_lock(&conn->mta_conn_mutex);
@@ -2836,6 +2851,11 @@ int ha_spider::index_read_last_map_internal(
       }
       if ((error_num = dbton_hdl->set_sql_for_exec(sql_type, roop_count)))
       {
+        if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
+        {
+          SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+          pthread_mutex_unlock(&conn->mta_conn_mutex);
+        }
         DBUG_RETURN(error_num);
       }
       if (!dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
@@ -2854,11 +2874,15 @@ int ha_spider::index_read_last_map_internal(
       } else {
 #endif
         conn->need_mon = &need_mons[roop_count];
+        DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = TRUE;
         conn->mta_conn_mutex_unlock_later = TRUE;
         if ((error_num = spider_db_set_names(this, conn,
           roop_count)))
         {
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -2894,6 +2918,8 @@ int ha_spider::index_read_last_map_internal(
           result_list.quick_mode,
           &need_mons[roop_count])
         ) {
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           error_num = spider_db_errorno(conn);
@@ -2921,6 +2947,8 @@ int ha_spider::index_read_last_map_internal(
           DBUG_RETURN(check_error_mode_eof(error_num));
         }
         connection_ids[roop_count] = conn->connection_id;
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         if (roop_count == link_ok)
@@ -3299,6 +3327,7 @@ int ha_spider::index_first_internal(
         }
 #endif
         spider_db_handler *dbton_hdl = dbton_handler[conn->dbton_id];
+        pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
         if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
         {
           pthread_mutex_lock(&conn->mta_conn_mutex);
@@ -3307,6 +3336,11 @@ int ha_spider::index_first_internal(
         if ((error_num =
           dbton_hdl->set_sql_for_exec(sql_type, roop_count)))
         {
+          if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
+          {
+            SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+            pthread_mutex_unlock(&conn->mta_conn_mutex);
+          }
           DBUG_RETURN(error_num);
         }
         if (!dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
@@ -3325,11 +3359,15 @@ int ha_spider::index_first_internal(
         } else {
 #endif
           conn->need_mon = &need_mons[roop_count];
+          DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = TRUE;
           conn->mta_conn_mutex_unlock_later = TRUE;
           if ((error_num = spider_db_set_names(this, conn,
             roop_count)))
           {
+            DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+            DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
             conn->mta_conn_mutex_lock_already = FALSE;
             conn->mta_conn_mutex_unlock_later = FALSE;
             SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -3365,6 +3403,8 @@ int ha_spider::index_first_internal(
             result_list.quick_mode,
             &need_mons[roop_count])
           ) {
+            DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+            DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
             conn->mta_conn_mutex_lock_already = FALSE;
             conn->mta_conn_mutex_unlock_later = FALSE;
             error_num = spider_db_errorno(conn);
@@ -3392,6 +3432,8 @@ int ha_spider::index_first_internal(
             DBUG_RETURN(check_error_mode_eof(error_num));
           }
           connection_ids[roop_count] = conn->connection_id;
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           if (roop_count == link_ok)
@@ -3687,6 +3729,7 @@ int ha_spider::index_last_internal(
         }
 #endif
         spider_db_handler *dbton_hdl = dbton_handler[conn->dbton_id];
+        pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
         if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
         {
           pthread_mutex_lock(&conn->mta_conn_mutex);
@@ -3695,6 +3738,11 @@ int ha_spider::index_last_internal(
         if ((error_num =
           dbton_hdl->set_sql_for_exec(sql_type, roop_count)))
         {
+          if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
+          {
+            SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+            pthread_mutex_unlock(&conn->mta_conn_mutex);
+          }
           DBUG_RETURN(error_num);
         }
         if (!dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
@@ -3713,11 +3761,15 @@ int ha_spider::index_last_internal(
         } else {
 #endif
           conn->need_mon = &need_mons[roop_count];
+          DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = TRUE;
           conn->mta_conn_mutex_unlock_later = TRUE;
           if ((error_num = spider_db_set_names(this, conn,
             roop_count)))
           {
+            DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+            DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
             conn->mta_conn_mutex_lock_already = FALSE;
             conn->mta_conn_mutex_unlock_later = FALSE;
             SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -3753,6 +3805,8 @@ int ha_spider::index_last_internal(
             result_list.quick_mode,
             &need_mons[roop_count])
           ) {
+            DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+            DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
             conn->mta_conn_mutex_lock_already = FALSE;
             conn->mta_conn_mutex_unlock_later = FALSE;
             error_num = spider_db_errorno(conn);
@@ -3780,6 +3834,8 @@ int ha_spider::index_last_internal(
             DBUG_RETURN(check_error_mode_eof(error_num));
           }
           connection_ids[roop_count] = conn->connection_id;
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           if (roop_count == link_ok)
@@ -4135,6 +4191,7 @@ int ha_spider::read_range_first_internal(
       }
 #endif
       spider_db_handler *dbton_hdl = dbton_handler[conn->dbton_id];
+      pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
       if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
       {
         pthread_mutex_lock(&conn->mta_conn_mutex);
@@ -4142,6 +4199,11 @@ int ha_spider::read_range_first_internal(
       }
       if ((error_num = dbton_hdl->set_sql_for_exec(sql_type, roop_count)))
       {
+        if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
+        {
+          SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+          pthread_mutex_unlock(&conn->mta_conn_mutex);
+        }
         DBUG_RETURN(error_num);
       }
       if (!dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
@@ -4160,11 +4222,15 @@ int ha_spider::read_range_first_internal(
       } else {
 #endif
         conn->need_mon = &need_mons[roop_count];
+        DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = TRUE;
         conn->mta_conn_mutex_unlock_later = TRUE;
         if ((error_num = spider_db_set_names(this, conn,
           roop_count)))
         {
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -4200,6 +4266,8 @@ int ha_spider::read_range_first_internal(
           result_list.quick_mode,
           &need_mons[roop_count])
         ) {
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           error_num = spider_db_errorno(conn);
@@ -4227,6 +4295,8 @@ int ha_spider::read_range_first_internal(
           DBUG_RETURN(check_error_mode_eof(error_num));
         }
         connection_ids[roop_count] = conn->connection_id;
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         if (roop_count == link_ok)
@@ -4824,6 +4894,7 @@ int ha_spider::read_multi_range_first_internal(
           }
 #endif
           spider_db_handler *dbton_hdl = dbton_handler[conn->dbton_id];
+          pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
           if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
           {
             pthread_mutex_lock(&conn->mta_conn_mutex);
@@ -4832,6 +4903,11 @@ int ha_spider::read_multi_range_first_internal(
           if ((error_num =
             dbton_hdl->set_sql_for_exec(sql_type, roop_count)))
           {
+            if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
+            {
+              SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+              pthread_mutex_unlock(&conn->mta_conn_mutex);
+            }
             DBUG_RETURN(error_num);
           }
           if (!dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
@@ -4856,11 +4932,15 @@ int ha_spider::read_multi_range_first_internal(
           } else {
 #endif
             conn->need_mon = &need_mons[roop_count];
+            DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+            DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
             conn->mta_conn_mutex_lock_already = TRUE;
             conn->mta_conn_mutex_unlock_later = TRUE;
             if ((error_num = spider_db_set_names(this, conn,
               roop_count)))
             {
+              DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+              DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
               conn->mta_conn_mutex_lock_already = FALSE;
               conn->mta_conn_mutex_unlock_later = FALSE;
               SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -4897,6 +4977,8 @@ int ha_spider::read_multi_range_first_internal(
                 result_list.quick_mode,
                 &need_mons[roop_count])
               ) {
+                DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+                DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
                 conn->mta_conn_mutex_lock_already = FALSE;
                 conn->mta_conn_mutex_unlock_later = FALSE;
                 error_num = spider_db_errorno(conn);
@@ -4926,6 +5008,8 @@ int ha_spider::read_multi_range_first_internal(
             if (!error_num)
             {
               connection_ids[roop_count] = conn->connection_id;
+              DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+              DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
               conn->mta_conn_mutex_lock_already = FALSE;
               conn->mta_conn_mutex_unlock_later = FALSE;
               if (roop_count == link_ok)
@@ -5634,6 +5718,7 @@ int ha_spider::read_multi_range_first_internal(
           }
 #endif
           spider_db_handler *dbton_hdl = dbton_handler[conn->dbton_id];
+          pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
           if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
           {
             pthread_mutex_lock(&conn->mta_conn_mutex);
@@ -5642,6 +5727,11 @@ int ha_spider::read_multi_range_first_internal(
           if ((error_num =
             dbton_hdl->set_sql_for_exec(sql_type, roop_count)))
           {
+            if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
+            {
+              SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+              pthread_mutex_unlock(&conn->mta_conn_mutex);
+            }
             DBUG_RETURN(error_num);
           }
           if (!dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
@@ -5667,11 +5757,15 @@ int ha_spider::read_multi_range_first_internal(
           } else {
 #endif
             conn->need_mon = &need_mons[roop_count];
+            DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+            DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
             conn->mta_conn_mutex_lock_already = TRUE;
             conn->mta_conn_mutex_unlock_later = TRUE;
             if ((error_num = spider_db_set_names(this, conn,
               roop_count)))
             {
+              DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+              DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
               conn->mta_conn_mutex_lock_already = FALSE;
               conn->mta_conn_mutex_unlock_later = FALSE;
               SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -5714,6 +5808,8 @@ int ha_spider::read_multi_range_first_internal(
                 -1,
                 &need_mons[roop_count])
               ) {
+                DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+                DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
                 conn->mta_conn_mutex_lock_already = FALSE;
                 conn->mta_conn_mutex_unlock_later = FALSE;
                 error_num = spider_db_errorno(conn);
@@ -5750,6 +5846,8 @@ int ha_spider::read_multi_range_first_internal(
               result_list.quick_mode,
               &need_mons[roop_count])
             ) {
+              DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+              DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
               conn->mta_conn_mutex_lock_already = FALSE;
               conn->mta_conn_mutex_unlock_later = FALSE;
               error_num = spider_db_errorno(conn);
@@ -5777,6 +5875,8 @@ int ha_spider::read_multi_range_first_internal(
               break;
             }
             connection_ids[roop_count] = conn->connection_id;
+            DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+            DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
             conn->mta_conn_mutex_lock_already = FALSE;
             conn->mta_conn_mutex_unlock_later = FALSE;
             if (roop_count == link_ok)
@@ -6294,6 +6394,7 @@ int ha_spider::read_multi_range_next(
           }
 #endif
           spider_db_handler *dbton_hdl = dbton_handler[conn->dbton_id];
+          pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
           if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
           {
             pthread_mutex_lock(&conn->mta_conn_mutex);
@@ -6302,6 +6403,11 @@ int ha_spider::read_multi_range_next(
           if ((error_num =
             dbton_hdl->set_sql_for_exec(sql_type, roop_count)))
           {
+            if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
+            {
+              SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+              pthread_mutex_unlock(&conn->mta_conn_mutex);
+            }
             DBUG_RETURN(error_num);
           }
           if (!dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
@@ -6326,11 +6432,15 @@ int ha_spider::read_multi_range_next(
           } else {
 #endif
             conn->need_mon = &need_mons[roop_count];
+            DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+            DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
             conn->mta_conn_mutex_lock_already = TRUE;
             conn->mta_conn_mutex_unlock_later = TRUE;
             if ((error_num = spider_db_set_names(this, conn,
               roop_count)))
             {
+              DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+              DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
               conn->mta_conn_mutex_lock_already = FALSE;
               conn->mta_conn_mutex_unlock_later = FALSE;
               SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -6367,6 +6477,8 @@ int ha_spider::read_multi_range_next(
                 result_list.quick_mode,
                 &need_mons[roop_count])
               ) {
+                DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+                DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
                 conn->mta_conn_mutex_lock_already = FALSE;
                 conn->mta_conn_mutex_unlock_later = FALSE;
                 error_num = spider_db_errorno(conn);
@@ -6396,6 +6508,8 @@ int ha_spider::read_multi_range_next(
             if (!error_num)
             {
               connection_ids[roop_count] = conn->connection_id;
+              DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+              DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
               conn->mta_conn_mutex_lock_already = FALSE;
               conn->mta_conn_mutex_unlock_later = FALSE;
               if (roop_count == link_ok)
@@ -7099,6 +7213,7 @@ int ha_spider::read_multi_range_next(
           }
 #endif
           spider_db_handler *dbton_hdl = dbton_handler[conn->dbton_id];
+          pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
           if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
           {
             pthread_mutex_lock(&conn->mta_conn_mutex);
@@ -7107,6 +7222,11 @@ int ha_spider::read_multi_range_next(
           if ((error_num =
             dbton_hdl->set_sql_for_exec(sql_type, roop_count)))
           {
+            if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
+            {
+              SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+              pthread_mutex_unlock(&conn->mta_conn_mutex);
+            }
             DBUG_RETURN(error_num);
           }
           if (!dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
@@ -7132,11 +7252,15 @@ int ha_spider::read_multi_range_next(
           } else {
 #endif
             conn->need_mon = &need_mons[roop_count];
+            DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+            DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
             conn->mta_conn_mutex_lock_already = TRUE;
             conn->mta_conn_mutex_unlock_later = TRUE;
             if ((error_num = spider_db_set_names(this, conn,
               roop_count)))
             {
+              DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+              DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
               conn->mta_conn_mutex_lock_already = FALSE;
               conn->mta_conn_mutex_unlock_later = FALSE;
               SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -7179,6 +7303,8 @@ int ha_spider::read_multi_range_next(
                 -1,
                 &need_mons[roop_count])
               ) {
+                DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+                DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
                 conn->mta_conn_mutex_lock_already = FALSE;
                 conn->mta_conn_mutex_unlock_later = FALSE;
                 error_num = spider_db_errorno(conn);
@@ -7215,6 +7341,8 @@ int ha_spider::read_multi_range_next(
               result_list.quick_mode,
               &need_mons[roop_count])
             ) {
+              DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+              DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
               conn->mta_conn_mutex_lock_already = FALSE;
               conn->mta_conn_mutex_unlock_later = FALSE;
               error_num = spider_db_errorno(conn);
@@ -7242,6 +7370,8 @@ int ha_spider::read_multi_range_next(
               break;
             }
             connection_ids[roop_count] = conn->connection_id;
+            DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+            DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
             conn->mta_conn_mutex_lock_already = FALSE;
             conn->mta_conn_mutex_unlock_later = FALSE;
             if (roop_count == link_ok)
@@ -7765,6 +7895,7 @@ int ha_spider::rnd_next_internal(
           sql_type = SPIDER_SQL_TYPE_HANDLER;
         }
         spider_db_handler *dbton_hdl = dbton_handler[conn->dbton_id];
+        pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
         if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
         {
           pthread_mutex_lock(&conn->mta_conn_mutex);
@@ -7773,6 +7904,11 @@ int ha_spider::rnd_next_internal(
         if ((error_num =
           dbton_hdl->set_sql_for_exec(sql_type, roop_count)))
         {
+          if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
+          {
+            SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+            pthread_mutex_unlock(&conn->mta_conn_mutex);
+          }
           DBUG_RETURN(error_num);
         }
         if (!dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
@@ -7782,11 +7918,15 @@ int ha_spider::rnd_next_internal(
         }
         DBUG_PRINT("info",("spider sql_type=%lu", sql_type));
         conn->need_mon = &need_mons[roop_count];
+        DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = TRUE;
         conn->mta_conn_mutex_unlock_later = TRUE;
         if ((error_num = spider_db_set_names(this, conn,
           roop_count)))
         {
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -7822,6 +7962,8 @@ int ha_spider::rnd_next_internal(
           result_list.quick_mode,
           &need_mons[roop_count])
         ) {
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           error_num = spider_db_errorno(conn);
@@ -7849,6 +7991,8 @@ int ha_spider::rnd_next_internal(
           DBUG_RETURN(check_error_mode_eof(error_num));
         }
         connection_ids[roop_count] = conn->connection_id;
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         if (roop_count == link_ok)
@@ -8381,6 +8525,7 @@ int ha_spider::ft_read_internal(
         uint dbton_id = share->use_sql_dbton_ids[roop_count];
         spider_db_handler *dbton_hdl = dbton_handler[dbton_id];
         SPIDER_CONN *conn = conns[roop_count];
+        pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
         if (dbton_hdl->need_lock_before_set_sql_for_exec(
           SPIDER_SQL_TYPE_SELECT_SQL))
         {
@@ -8390,6 +8535,12 @@ int ha_spider::ft_read_internal(
         if ((error_num = dbton_hdl->set_sql_for_exec(
           SPIDER_SQL_TYPE_SELECT_SQL, roop_count)))
         {
+          if (dbton_hdl->need_lock_before_set_sql_for_exec(
+            SPIDER_SQL_TYPE_SELECT_SQL))
+          {
+            SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+            pthread_mutex_unlock(&conn->mta_conn_mutex);
+          }
           DBUG_RETURN(error_num);
         }
         if (!dbton_hdl->need_lock_before_set_sql_for_exec(
@@ -8399,10 +8550,14 @@ int ha_spider::ft_read_internal(
           SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
         }
         conn->need_mon = &need_mons[roop_count];
+        DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = TRUE;
         conn->mta_conn_mutex_unlock_later = TRUE;
         if ((error_num = spider_db_set_names(this, conn, roop_count)))
         {
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -8437,6 +8592,8 @@ int ha_spider::ft_read_internal(
           result_list.quick_mode,
           &need_mons[roop_count])
         ) {
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           error_num = spider_db_errorno(conn);
@@ -8464,6 +8621,8 @@ int ha_spider::ft_read_internal(
           DBUG_RETURN(check_error_mode_eof(error_num));
         }
         connection_ids[roop_count] = conn->connection_id;
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         if (roop_count == link_ok)
@@ -11300,9 +11459,12 @@ void ha_spider::bulk_req_exec()
     if (conn->bulk_access_requests)
     {
       spider_bg_conn_wait(conn);
+      pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
       pthread_mutex_lock(&conn->mta_conn_mutex);
       SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
       conn->need_mon = &need_mon;
+      DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = TRUE;
       conn->mta_conn_mutex_unlock_later = TRUE;
       /* currently only used for HS */
@@ -11320,6 +11482,8 @@ void ha_spider::bulk_req_exec()
       conn->bulk_access_sended += conn->bulk_access_requests;
 */
       conn->bulk_access_requests = 0;
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -13136,6 +13300,7 @@ int ha_spider::drop_tmp_tables()
         uint dbton_id = share->use_sql_dbton_ids[roop_count];
         spider_db_handler *dbton_hdl = dbton_handler[dbton_id];
         SPIDER_CONN *conn = conns[roop_count];
+        pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
         if (dbton_hdl->need_lock_before_set_sql_for_exec(
           SPIDER_SQL_TYPE_TMP_SQL))
         {
@@ -13145,6 +13310,12 @@ int ha_spider::drop_tmp_tables()
         if ((error_num = dbton_hdl->set_sql_for_exec(
           SPIDER_SQL_TYPE_TMP_SQL, roop_count)))
         {
+          if (dbton_hdl->need_lock_before_set_sql_for_exec(
+            SPIDER_SQL_TYPE_TMP_SQL))
+          {
+            SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+            pthread_mutex_unlock(&conn->mta_conn_mutex);
+          }
           DBUG_RETURN(error_num);
         }
         if (!dbton_hdl->need_lock_before_set_sql_for_exec(
@@ -13154,10 +13325,14 @@ int ha_spider::drop_tmp_tables()
           SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
         }
         conn->need_mon = &need_mon;
+        DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = TRUE;
         conn->mta_conn_mutex_unlock_later = TRUE;
         if ((tmp_error_num = spider_db_set_names(this, conn, roop_count)))
         {
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -13195,6 +13370,8 @@ int ha_spider::drop_tmp_tables()
             -1,
             &need_mons[roop_count])
           ) {
+            DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+            DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
             conn->mta_conn_mutex_lock_already = FALSE;
             conn->mta_conn_mutex_unlock_later = FALSE;
             tmp_error_num = spider_db_errorno(conn);
@@ -13221,6 +13398,8 @@ int ha_spider::drop_tmp_tables()
             }
             error_num = tmp_error_num;
           } else {
+            DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+            DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
             conn->mta_conn_mutex_lock_already = FALSE;
             conn->mta_conn_mutex_unlock_later = FALSE;
             SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
diff --git a/storage/spider/spd_conn.cc b/storage/spider/spd_conn.cc
index 03afdfd68f8..1e973493ba8 100644
--- a/storage/spider/spd_conn.cc
+++ b/storage/spider/spd_conn.cc
@@ -2628,6 +2628,7 @@ void *spider_bg_conn_action(
           sql_type = SPIDER_SQL_TYPE_SELECT_HS;
         }
 #endif
+        pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
         if (dbton_handler->need_lock_before_set_sql_for_exec(sql_type))
         {
           pthread_mutex_lock(&conn->mta_conn_mutex);
@@ -2668,6 +2669,8 @@ void *spider_bg_conn_action(
         if (!result_list->bgs_error)
         {
           conn->need_mon = &spider->need_mons[conn->link_idx];
+          DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = TRUE;
           conn->mta_conn_mutex_unlock_later = TRUE;
 #ifdef HA_CAN_BULK_ACCESS
@@ -2745,6 +2748,8 @@ void *spider_bg_conn_action(
 #ifdef HA_CAN_BULK_ACCESS
           }
 #endif
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -2755,11 +2760,14 @@ void *spider_bg_conn_action(
         }
       } else {
         spider->connection_ids[conn->link_idx] = conn->connection_id;
+        pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+        DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_unlock_later = TRUE;
         result_list->bgs_error =
           spider_db_store_result(spider, conn->link_idx, result_list->table);
         if ((result_list->bgs_error_with_message = thd->is_error()))
           strmov(result_list->bgs_error_msg, spider_stmt_da_message(thd));
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_unlock_later = FALSE;
       }
       conn->bg_search = FALSE;
@@ -2823,12 +2831,26 @@ void *spider_bg_conn_action(
     {
       DBUG_PRINT("info",("spider bg exec sql start"));
       spider = (ha_spider*) conn->bg_target;
+      pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+      pthread_mutex_lock(&conn->mta_conn_mutex);
+      SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+      conn->need_mon = &spider->need_mons[conn->link_idx];
+      DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = TRUE;
+      conn->mta_conn_mutex_unlock_later = TRUE;
       *conn->bg_error_num = spider_db_query_with_set_names(
         conn->bg_sql_type,
         spider,
         conn,
         conn->link_idx
       );
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = FALSE;
+      conn->mta_conn_mutex_unlock_later = FALSE;
+      SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+      pthread_mutex_unlock(&conn->mta_conn_mutex);
       conn->bg_exec_sql = FALSE;
       continue;
     }
diff --git a/storage/spider/spd_db_conn.cc b/storage/spider/spd_db_conn.cc
index 08d2591a07e..6d2afc1fd55 100644
--- a/storage/spider/spd_db_conn.cc
+++ b/storage/spider/spd_db_conn.cc
@@ -214,22 +214,13 @@ int spider_db_ping_internal(
 ) {
   int error_num;
   DBUG_ENTER("spider_db_ping_internal");
-  if (!conn->mta_conn_mutex_lock_already)
-  {
-    pthread_mutex_lock(&conn->mta_conn_mutex);
-    SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
-    conn->need_mon = need_mon;
-  }
+  pthread_mutex_assert_owner(&conn->mta_conn_mutex);
   DBUG_ASSERT(conn->mta_conn_mutex_file_pos.file_name);
   if (conn->server_lost || conn->queued_connect)
   {
     if ((error_num = spider_db_connect(share, conn, all_link_idx)))
     {
-      if (!conn->mta_conn_mutex_unlock_later)
-      {
-        SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-        pthread_mutex_unlock(&conn->mta_conn_mutex);
-      }
+      pthread_mutex_assert_owner(&conn->mta_conn_mutex);
       DBUG_RETURN(error_num);
     }
     conn->server_lost = FALSE;
@@ -242,11 +233,7 @@ int spider_db_ping_internal(
     {
       DBUG_PRINT("info", ("spider conn=%p SERVER_LOST", conn));
       conn->server_lost = TRUE;
-      if (!conn->mta_conn_mutex_unlock_later)
-      {
-        SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-        pthread_mutex_unlock(&conn->mta_conn_mutex);
-      }
+      pthread_mutex_assert_owner(&conn->mta_conn_mutex);
       DBUG_RETURN(error_num);
     }
     if((error_num = conn->db_conn->ping()))
@@ -254,20 +241,12 @@ int spider_db_ping_internal(
       spider_db_disconnect(conn);
       DBUG_PRINT("info", ("spider conn=%p SERVER_LOST", conn));
       conn->server_lost = TRUE;
-      if (!conn->mta_conn_mutex_unlock_later)
-      {
-        SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-        pthread_mutex_unlock(&conn->mta_conn_mutex);
-      }
+      pthread_mutex_assert_owner(&conn->mta_conn_mutex);
       DBUG_RETURN(error_num);
     }
   }
   conn->ping_time = (time_t) time((time_t*) 0);
-  if (!conn->mta_conn_mutex_unlock_later)
-  {
-    SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-    pthread_mutex_unlock(&conn->mta_conn_mutex);
-  }
+  pthread_mutex_assert_owner(&conn->mta_conn_mutex);
   DBUG_RETURN(0);
 }
 
@@ -322,6 +301,7 @@ int spider_db_conn_queue_action(
     conn->queued_connect = FALSE;
   }
 
+  pthread_mutex_assert_owner(&conn->mta_conn_mutex);
 #if defined(HS_HAS_SQLCOM) && defined(HAVE_HANDLERSOCKET)
   if (conn->conn_kind == SPIDER_CONN_KIND_MYSQL)
   {
@@ -616,7 +596,6 @@ int spider_db_before_query(
   int *need_mon
 ) {
   int error_num;
-  bool tmp_mta_conn_mutex_lock_already;
   DBUG_ENTER("spider_db_before_query");
   DBUG_ASSERT(need_mon);
 #ifndef WITHOUT_SPIDER_BG_SEARCH
@@ -624,25 +603,18 @@ int spider_db_before_query(
     spider_bg_conn_break(conn, NULL);
 #endif
   conn->in_before_query = TRUE;
-  if (!conn->mta_conn_mutex_lock_already)
-  {
-    pthread_mutex_lock(&conn->mta_conn_mutex);
-    SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
-    conn->need_mon = need_mon;
-  }
+  pthread_mutex_assert_owner(&conn->mta_conn_mutex);
   DBUG_ASSERT(conn->mta_conn_mutex_file_pos.file_name);
-  tmp_mta_conn_mutex_lock_already = conn->mta_conn_mutex_lock_already;
-  conn->mta_conn_mutex_lock_already = TRUE;
   if ((error_num = spider_db_conn_queue_action(conn)))
   {
     conn->in_before_query = FALSE;
-    conn->mta_conn_mutex_lock_already = tmp_mta_conn_mutex_lock_already;
+    pthread_mutex_assert_owner(&conn->mta_conn_mutex);
     DBUG_RETURN(error_num);
   }
-  conn->mta_conn_mutex_lock_already = tmp_mta_conn_mutex_lock_already;
   if (conn->server_lost)
   {
     conn->in_before_query = FALSE;
+    pthread_mutex_assert_owner(&conn->mta_conn_mutex);
     DBUG_RETURN(CR_SERVER_GONE_ERROR);
   }
   DBUG_PRINT("info", ("spider conn[%p]->quick_target=%p",
@@ -669,6 +641,7 @@ int spider_db_before_query(
         ) {
           conn->mta_conn_mutex_unlock_later = tmp_mta_conn_mutex_unlock_later;
           conn->in_before_query = FALSE;
+          pthread_mutex_assert_owner(&conn->mta_conn_mutex);
           DBUG_RETURN(error_num);
         }
       }
@@ -684,6 +657,7 @@ int spider_db_before_query(
     }
   }
   conn->in_before_query = FALSE;
+  pthread_mutex_assert_owner(&conn->mta_conn_mutex);
   DBUG_RETURN(0);
 }
 
@@ -696,6 +670,7 @@ int spider_db_query(
 ) {
   int error_num;
   DBUG_ENTER("spider_db_query");
+  pthread_mutex_assert_owner(&conn->mta_conn_mutex);
 #if defined(HS_HAS_SQLCOM) && defined(HAVE_HANDLERSOCKET)
   if (conn->conn_kind == SPIDER_CONN_KIND_MYSQL)
   {
@@ -738,6 +713,7 @@ int spider_db_errorno(
   int error_num;
   DBUG_ENTER("spider_db_errorno");
   DBUG_ASSERT(conn->need_mon);
+  pthread_mutex_assert_owner(&conn->mta_conn_mutex);
 #if defined(HS_HAS_SQLCOM) && defined(HAVE_HANDLERSOCKET)
   if (conn->conn_kind == SPIDER_CONN_KIND_MYSQL)
   {
@@ -752,6 +728,7 @@ int spider_db_errorno(
       }
       if (!conn->mta_conn_mutex_unlock_later)
       {
+        DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
         pthread_mutex_unlock(&conn->mta_conn_mutex);
       }
@@ -773,6 +750,7 @@ int spider_db_errorno(
         }
         if (!conn->mta_conn_mutex_unlock_later)
         {
+          DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
           pthread_mutex_unlock(&conn->mta_conn_mutex);
         }
@@ -785,6 +763,7 @@ int spider_db_errorno(
         conn->error_length = strlen(conn->error_str);
         if (!conn->mta_conn_mutex_unlock_later)
         {
+          DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
           pthread_mutex_unlock(&conn->mta_conn_mutex);
         }
@@ -810,6 +789,7 @@ int spider_db_errorno(
         }
         if (!conn->mta_conn_mutex_unlock_later)
         {
+          DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
           pthread_mutex_unlock(&conn->mta_conn_mutex);
         }
@@ -831,6 +811,7 @@ int spider_db_errorno(
       }
       if (!conn->mta_conn_mutex_unlock_later)
       {
+        DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
         pthread_mutex_unlock(&conn->mta_conn_mutex);
       }
@@ -847,6 +828,7 @@ int spider_db_errorno(
       conn->server_lost = TRUE;
       if (!conn->mta_conn_mutex_unlock_later)
       {
+        DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
         pthread_mutex_unlock(&conn->mta_conn_mutex);
       }
@@ -856,6 +838,7 @@ int spider_db_errorno(
       *conn->need_mon = 0;
       if (!conn->mta_conn_mutex_unlock_later)
       {
+        DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
         pthread_mutex_unlock(&conn->mta_conn_mutex);
       }
@@ -878,6 +861,7 @@ int spider_db_errorno(
     *conn->need_mon = ER_SPIDER_HS_NUM;
     if (!conn->mta_conn_mutex_unlock_later)
     {
+      DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
       pthread_mutex_unlock(&conn->mta_conn_mutex);
     }
@@ -886,6 +870,7 @@ int spider_db_errorno(
 #endif
   if (!conn->mta_conn_mutex_unlock_later)
   {
+    DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
     pthread_mutex_unlock(&conn->mta_conn_mutex);
   }
@@ -908,33 +893,25 @@ int spider_db_set_names_internal(
   int all_link_idx,
   int *need_mon
 ) {
-  bool tmp_mta_conn_mutex_lock_already;
   DBUG_ENTER("spider_db_set_names_internal");
 #if defined(HS_HAS_SQLCOM) && defined(HAVE_HANDLERSOCKET)
   if (conn->conn_kind == SPIDER_CONN_KIND_MYSQL)
   {
 #endif
-    if (!conn->mta_conn_mutex_lock_already)
-    {
-      pthread_mutex_lock(&conn->mta_conn_mutex);
-      SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
-      conn->need_mon = need_mon;
-    }
+    pthread_mutex_assert_owner(&conn->mta_conn_mutex);
     DBUG_ASSERT(conn->mta_conn_mutex_file_pos.file_name);
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     if (
       !conn->access_charset ||
       share->access_charset->cset != conn->access_charset->cset
     ) {
-      tmp_mta_conn_mutex_lock_already = conn->mta_conn_mutex_lock_already;
-      conn->mta_conn_mutex_lock_already = TRUE;
       if (
         spider_db_before_query(conn, need_mon) ||
         conn->db_conn->set_character_set(share->access_charset->csname)
       ) {
-        conn->mta_conn_mutex_lock_already = tmp_mta_conn_mutex_lock_already;
         DBUG_RETURN(spider_db_errorno(conn));
       }
-      conn->mta_conn_mutex_lock_already = tmp_mta_conn_mutex_lock_already;
       conn->access_charset = share->access_charset;
     }
     if (
@@ -949,13 +926,10 @@ int spider_db_set_names_internal(
     ) {
       DBUG_PRINT("info",("spider all_link_idx=%d db=%s", all_link_idx,
         share->tgt_dbs[all_link_idx]));
-      tmp_mta_conn_mutex_lock_already = conn->mta_conn_mutex_lock_already;
-      conn->mta_conn_mutex_lock_already = TRUE;
       if (
         spider_db_before_query(conn, need_mon) ||
         conn->db_conn->select_db(share->tgt_dbs[all_link_idx])
       ) {
-        conn->mta_conn_mutex_lock_already = tmp_mta_conn_mutex_lock_already;
         DBUG_RETURN(spider_db_errorno(conn));
       }
       conn->default_database.length(0);
@@ -965,12 +939,6 @@ int spider_db_set_names_internal(
       conn->default_database.q_append(share->tgt_dbs[all_link_idx],
         share->tgt_dbs_lengths[all_link_idx] + 1);
       conn->default_database.length(share->tgt_dbs_lengths[all_link_idx]);
-      conn->mta_conn_mutex_lock_already = tmp_mta_conn_mutex_lock_already;
-    }
-    if (!conn->mta_conn_mutex_unlock_later)
-    {
-      SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-      pthread_mutex_unlock(&conn->mta_conn_mutex);
     }
 #if defined(HS_HAS_SQLCOM) && defined(HAVE_HANDLERSOCKET)
   }
@@ -999,19 +967,11 @@ int spider_db_query_with_set_names(
   spider_db_handler *dbton_hdl = spider->dbton_handler[conn->dbton_id];
   DBUG_ENTER("spider_db_query_with_set_names");
 
-/*
-  pthread_mutex_lock(&conn->mta_conn_mutex);
-  SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
-*/
-  conn->need_mon = &spider->need_mons[link_idx];
-  conn->mta_conn_mutex_lock_already = TRUE;
-  conn->mta_conn_mutex_unlock_later = TRUE;
+  pthread_mutex_assert_owner(&conn->mta_conn_mutex);
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
   if ((error_num = spider_db_set_names(spider, conn, link_idx)))
   {
-    conn->mta_conn_mutex_lock_already = FALSE;
-    conn->mta_conn_mutex_unlock_later = FALSE;
-    SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-    pthread_mutex_unlock(&conn->mta_conn_mutex);
     if (
       share->monitoring_kind[link_idx] &&
       spider->need_mons[link_idx]
@@ -1043,8 +1003,6 @@ int spider_db_query_with_set_names(
     -1,
     &spider->need_mons[link_idx])
   ) {
-    conn->mta_conn_mutex_lock_already = FALSE;
-    conn->mta_conn_mutex_unlock_later = FALSE;
     error_num = spider_db_errorno(conn);
     if (
       share->monitoring_kind[link_idx] &&
@@ -1069,10 +1027,6 @@ int spider_db_query_with_set_names(
     }
     DBUG_RETURN(error_num);
   }
-  conn->mta_conn_mutex_lock_already = FALSE;
-  conn->mta_conn_mutex_unlock_later = FALSE;
-  SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-  pthread_mutex_unlock(&conn->mta_conn_mutex);
   DBUG_RETURN(0);
 }
 
@@ -1086,15 +1040,16 @@ int spider_db_query_for_bulk_update(
   SPIDER_SHARE *share = spider->share;
   DBUG_ENTER("spider_db_query_for_bulk_update");
 
-/*
-  pthread_mutex_lock(&conn->mta_conn_mutex);
-  SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
-*/
+  pthread_mutex_assert_owner(&conn->mta_conn_mutex);
   conn->need_mon = &spider->need_mons[link_idx];
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = TRUE;
   conn->mta_conn_mutex_unlock_later = TRUE;
   if ((error_num = spider_db_set_names(spider, conn, link_idx)))
   {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -1131,6 +1086,8 @@ int spider_db_query_for_bulk_update(
     -1,
     &spider->need_mons[link_idx])
   ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     error_num = spider_db_errorno(conn);
@@ -1178,6 +1135,8 @@ int spider_db_query_for_bulk_update(
   }
   if (error_num > 0 && !conn->db_conn->is_dup_entry_error(error_num))
   {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -1205,6 +1164,8 @@ int spider_db_query_for_bulk_update(
     }
     DBUG_RETURN(error_num);
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = FALSE;
   conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -3952,6 +3913,7 @@ int spider_db_store_result(
         ER_SPIDER_REMOTE_SERVER_GONE_AWAY_STR, MYF(0));
       if (!conn->mta_conn_mutex_unlock_later)
       {
+        DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
         pthread_mutex_unlock(&conn->mta_conn_mutex);
       }
@@ -3968,6 +3930,7 @@ int spider_db_store_result(
         ) {
           if (!conn->mta_conn_mutex_unlock_later)
           {
+            DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
             SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
             pthread_mutex_unlock(&conn->mta_conn_mutex);
           }
@@ -3999,6 +3962,7 @@ int spider_db_store_result(
           ) {
             if (!conn->mta_conn_mutex_unlock_later)
             {
+              DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
               SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
               pthread_mutex_unlock(&conn->mta_conn_mutex);
             }
@@ -4042,6 +4006,7 @@ int spider_db_store_result(
           ) {
             if (!conn->mta_conn_mutex_unlock_later)
             {
+              DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
               SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
               pthread_mutex_unlock(&conn->mta_conn_mutex);
             }
@@ -4081,6 +4046,7 @@ int spider_db_store_result(
         {
           if (!conn->mta_conn_mutex_unlock_later)
           {
+            DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
             SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
             pthread_mutex_unlock(&conn->mta_conn_mutex);
           }
@@ -4109,6 +4075,7 @@ int spider_db_store_result(
 #endif
         if (!conn->mta_conn_mutex_unlock_later && !call_db_errorno)
         {
+          DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
           pthread_mutex_unlock(&conn->mta_conn_mutex);
         }
@@ -4116,6 +4083,7 @@ int spider_db_store_result(
       } else {
         if (!conn->mta_conn_mutex_unlock_later)
         {
+          DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
           pthread_mutex_unlock(&conn->mta_conn_mutex);
         }
@@ -4159,6 +4127,7 @@ int spider_db_store_result(
         result_list->limit_num -= current->prev->record_num;
         if (!conn->mta_conn_mutex_unlock_later)
         {
+          DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
           pthread_mutex_unlock(&conn->mta_conn_mutex);
         }
@@ -4182,6 +4151,7 @@ int spider_db_store_result(
           } else {
             if (!conn->mta_conn_mutex_unlock_later)
             {
+              DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
               SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
               pthread_mutex_unlock(&conn->mta_conn_mutex);
             }
@@ -4193,6 +4163,7 @@ int spider_db_store_result(
         spider->quick_targets[link_idx] = spider;
         if (!conn->mta_conn_mutex_unlock_later)
         {
+          DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
           pthread_mutex_unlock(&conn->mta_conn_mutex);
         }
@@ -4423,6 +4394,7 @@ int spider_db_store_result(
         ER_SPIDER_REMOTE_SERVER_GONE_AWAY_STR, MYF(0));
       if (!conn->mta_conn_mutex_unlock_later)
       {
+        DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
         pthread_mutex_unlock(&conn->mta_conn_mutex);
       }
@@ -4448,6 +4420,7 @@ int spider_db_store_result(
       } else {
         if (!conn->mta_conn_mutex_unlock_later)
         {
+          DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
           pthread_mutex_unlock(&conn->mta_conn_mutex);
         }
@@ -4458,6 +4431,7 @@ int spider_db_store_result(
     result_list->hs_has_result = TRUE;
     if (!conn->mta_conn_mutex_unlock_later)
     {
+      DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
       pthread_mutex_unlock(&conn->mta_conn_mutex);
     }
@@ -4543,15 +4517,15 @@ int spider_db_bulk_store_result(
   error_num = spider_db_bulk_open_handler(spider, conn, link_idx);
   if (!discard_result)
   {
-    bool tmp_mta_conn_mutex_unlock_later;
-    tmp_mta_conn_mutex_unlock_later = conn->mta_conn_mutex_unlock_later;
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+    DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_unlock_later = TRUE;
     if ((tmp_error_num = spider_db_store_result(spider, link_idx,
       spider->get_table())))
     {
       error_num = tmp_error_num;
     }
-    conn->mta_conn_mutex_unlock_later = tmp_mta_conn_mutex_unlock_later;
+    conn->mta_conn_mutex_unlock_later = FALSE;
   } else {
     if (spider->connection_ids[link_idx] == conn->connection_id)
       spider_db_discard_result(spider, link_idx, conn);
@@ -4780,6 +4754,7 @@ int spider_db_seek_next(
               link_idx = link_idx_holder->link_idx;
               spider_db_handler *dbton_handler =
                 spider->dbton_handler[conn->dbton_id];
+              pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
               if (dbton_handler->need_lock_before_set_sql_for_exec(sql_type))
               {
                 pthread_mutex_lock(&conn->mta_conn_mutex);
@@ -4788,6 +4763,11 @@ int spider_db_seek_next(
               if ((error_num = dbton_handler->set_sql_for_exec(sql_type,
                 link_idx)))
               {
+                if (dbton_handler->need_lock_before_set_sql_for_exec(sql_type))
+                {
+                  SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+                  pthread_mutex_unlock(&conn->mta_conn_mutex);
+                }
                 DBUG_PRINT("info",("spider error_num 6=%d", error_num));
                 DBUG_RETURN(error_num);
               }
@@ -4797,10 +4777,14 @@ int spider_db_seek_next(
                 SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
               }
               conn->need_mon = &spider->need_mons[link_idx];
+              DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+              DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
               conn->mta_conn_mutex_lock_already = TRUE;
               conn->mta_conn_mutex_unlock_later = TRUE;
               if ((error_num = spider_db_set_names(spider, conn, link_idx)))
               {
+                DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+                DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
                 conn->mta_conn_mutex_lock_already = FALSE;
                 conn->mta_conn_mutex_unlock_later = FALSE;
                 SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -4821,6 +4805,8 @@ int spider_db_seek_next(
                 result_list->quick_mode,
                 &spider->need_mons[link_idx])
               ) {
+                DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+                DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
                 conn->mta_conn_mutex_lock_already = FALSE;
                 conn->mta_conn_mutex_unlock_later = FALSE;
                 error_num = spider_db_errorno(conn);
@@ -4833,6 +4819,8 @@ int spider_db_seek_next(
                 DBUG_RETURN(error_num);
               }
               spider->connection_ids[link_idx] = conn->connection_id;
+              DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+              DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
               conn->mta_conn_mutex_lock_already = FALSE;
               conn->mta_conn_mutex_unlock_later = FALSE;
               if (fields->is_first_link_ok_chain(link_idx_chain))
@@ -4874,6 +4862,7 @@ int spider_db_seek_next(
               }
               spider_db_handler *dbton_handler =
                 spider->dbton_handler[conn->dbton_id];
+              pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
               if (dbton_handler->need_lock_before_set_sql_for_exec(sql_type))
               {
                 pthread_mutex_lock(&conn->mta_conn_mutex);
@@ -4882,6 +4871,11 @@ int spider_db_seek_next(
               if ((error_num = dbton_handler->set_sql_for_exec(sql_type,
                 roop_count)))
               {
+                if (dbton_handler->need_lock_before_set_sql_for_exec(sql_type))
+                {
+                  SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+                  pthread_mutex_unlock(&conn->mta_conn_mutex);
+                }
                 DBUG_PRINT("info",("spider error_num 6=%d", error_num));
                 DBUG_RETURN(error_num);
               }
@@ -4891,10 +4885,14 @@ int spider_db_seek_next(
                 SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
               }
               conn->need_mon = &spider->need_mons[roop_count];
+              DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+              DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
               conn->mta_conn_mutex_lock_already = TRUE;
               conn->mta_conn_mutex_unlock_later = TRUE;
               if ((error_num = spider_db_set_names(spider, conn, roop_count)))
               {
+                DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+                DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
                 conn->mta_conn_mutex_lock_already = FALSE;
                 conn->mta_conn_mutex_unlock_later = FALSE;
                 SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -4931,6 +4929,8 @@ int spider_db_seek_next(
                 result_list->quick_mode,
                 &spider->need_mons[roop_count])
               ) {
+                DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+                DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
                 conn->mta_conn_mutex_lock_already = FALSE;
                 conn->mta_conn_mutex_unlock_later = FALSE;
                 error_num = spider_db_errorno(conn);
@@ -4959,6 +4959,8 @@ int spider_db_seek_next(
                 DBUG_RETURN(error_num);
               }
               spider->connection_ids[roop_count] = conn->connection_id;
+              DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+              DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
               conn->mta_conn_mutex_lock_already = FALSE;
               conn->mta_conn_mutex_unlock_later = FALSE;
               if (roop_count == link_ok)
@@ -5003,6 +5005,8 @@ int spider_db_seek_next(
 #endif
         } else {
           spider->connection_ids[link_idx] = conn->connection_id;
+          pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+          DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_unlock_later = TRUE;
           if ((error_num = spider_db_store_result(spider, link_idx, table)))
           {
@@ -5129,6 +5133,7 @@ int spider_db_seek_last(
       }
       conn = spider->conns[roop_count];
       spider_db_handler *dbton_handler = spider->dbton_handler[conn->dbton_id];
+      pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
       if (dbton_handler->need_lock_before_set_sql_for_exec(sql_type))
       {
         pthread_mutex_lock(&conn->mta_conn_mutex);
@@ -5136,6 +5141,11 @@ int spider_db_seek_last(
       }
       if ((error_num = dbton_handler->set_sql_for_exec(sql_type, roop_count)))
       {
+        if (dbton_handler->need_lock_before_set_sql_for_exec(sql_type))
+        {
+          SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+          pthread_mutex_unlock(&conn->mta_conn_mutex);
+        }
         DBUG_RETURN(error_num);
       }
       if (!dbton_handler->need_lock_before_set_sql_for_exec(sql_type))
@@ -5145,10 +5155,14 @@ int spider_db_seek_last(
       }
       DBUG_PRINT("info",("spider sql_type=%lu", sql_type));
       conn->need_mon = &spider->need_mons[roop_count];
+      DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = TRUE;
       conn->mta_conn_mutex_unlock_later = TRUE;
       if ((error_num = spider_db_set_names(spider, conn, roop_count)))
       {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -5184,6 +5198,8 @@ int spider_db_seek_last(
         result_list->quick_mode,
         &spider->need_mons[roop_count])
       ) {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         error_num = spider_db_errorno(conn);
@@ -5211,6 +5227,8 @@ int spider_db_seek_last(
         DBUG_RETURN(error_num);
       }
       spider->connection_ids[roop_count] = conn->connection_id;
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       if (roop_count == link_ok)
@@ -5332,6 +5350,7 @@ int spider_db_seek_last(
     }
     conn = spider->conns[roop_count];
     spider_db_handler *dbton_handler = spider->dbton_handler[conn->dbton_id];
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
     if (dbton_handler->need_lock_before_set_sql_for_exec(sql_type))
     {
       pthread_mutex_lock(&conn->mta_conn_mutex);
@@ -5339,6 +5358,11 @@ int spider_db_seek_last(
     }
     if ((error_num = dbton_handler->set_sql_for_exec(sql_type, roop_count)))
     {
+      if (dbton_handler->need_lock_before_set_sql_for_exec(sql_type))
+      {
+        SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+        pthread_mutex_unlock(&conn->mta_conn_mutex);
+      }
       DBUG_RETURN(error_num);
     }
     if (!dbton_handler->need_lock_before_set_sql_for_exec(sql_type))
@@ -5348,10 +5372,14 @@ int spider_db_seek_last(
     }
     DBUG_PRINT("info",("spider sql_type=%lu", sql_type));
     conn->need_mon = &spider->need_mons[roop_count];
+    DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = TRUE;
     conn->mta_conn_mutex_unlock_later = TRUE;
     if ((error_num = spider_db_set_names(spider, conn, roop_count)))
     {
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -5387,6 +5415,8 @@ int spider_db_seek_last(
       result_list->quick_mode,
       &spider->need_mons[roop_count])
     ) {
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       error_num = spider_db_errorno(conn);
@@ -5414,6 +5444,8 @@ int spider_db_seek_last(
       DBUG_RETURN(error_num);
     }
     spider->connection_ids[roop_count] = conn->connection_id;
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     if (roop_count == link_ok)
@@ -6124,8 +6156,6 @@ int spider_db_bulk_insert(
 #endif
   SPIDER_SHARE *share = spider->share;
   THD *thd = spider->trx->thd;
-  bool mta_conn_mutex_lock_already_backup;
-  bool mta_conn_mutex_unlock_later_backup;
   DBUG_ENTER("spider_db_bulk_insert");
 
   if (!bulk_end)
@@ -6181,61 +6211,50 @@ int spider_db_bulk_insert(
           sql_type = SPIDER_SQL_TYPE_INSERT_SQL;
           conn = spider->conns[roop_count2];
           dbton_handler = spider->dbton_handler[conn->dbton_id];
-          mta_conn_mutex_lock_already_backup =
-            conn->mta_conn_mutex_lock_already;
-          mta_conn_mutex_unlock_later_backup =
-            conn->mta_conn_mutex_unlock_later;
+          pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
           if (dbton_handler->need_lock_before_set_sql_for_exec(sql_type))
           {
-            if (!mta_conn_mutex_lock_already_backup)
-            {
-              pthread_mutex_lock(&conn->mta_conn_mutex);
-              SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
-            }
+            pthread_mutex_lock(&conn->mta_conn_mutex);
+            SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
           }
           if ((error_num = dbton_handler->set_sql_for_exec(sql_type,
             roop_count2)))
           {
+            if (dbton_handler->need_lock_before_set_sql_for_exec(sql_type))
+            {
+              SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+              pthread_mutex_unlock(&conn->mta_conn_mutex);
+            }
             DBUG_RETURN(error_num);
           }
           if (!dbton_handler->need_lock_before_set_sql_for_exec(sql_type))
           {
-            if (!mta_conn_mutex_lock_already_backup)
-            {
-              pthread_mutex_lock(&conn->mta_conn_mutex);
-              SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
-            }
+            pthread_mutex_lock(&conn->mta_conn_mutex);
+            SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
           }
 #if defined(HS_HAS_SQLCOM) && defined(HAVE_HANDLERSOCKET)
         } else {
           sql_type = SPIDER_SQL_TYPE_INSERT_HS;
           conn = spider->hs_w_conns[roop_count2];
           dbton_handler = spider->dbton_handler[conn->dbton_id];
-          mta_conn_mutex_lock_already_backup =
-            conn->mta_conn_mutex_lock_already;
-          mta_conn_mutex_unlock_later_backup =
-            conn->mta_conn_mutex_unlock_later;
-          if (!mta_conn_mutex_lock_already_backup)
-          {
-            pthread_mutex_lock(&conn->mta_conn_mutex);
-            SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
-          }
+          pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+          pthread_mutex_lock(&conn->mta_conn_mutex);
+          SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
         }
 #endif
         conn->need_mon = &spider->need_mons[roop_count2];
+        DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = TRUE;
         conn->mta_conn_mutex_unlock_later = TRUE;
         if ((error_num = spider_db_set_names(spider, conn, roop_count2)))
         {
-          conn->mta_conn_mutex_lock_already =
-            mta_conn_mutex_lock_already_backup;
-          conn->mta_conn_mutex_unlock_later =
-            mta_conn_mutex_unlock_later_backup;
-          if (!mta_conn_mutex_unlock_later_backup)
-          {
-            SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-            pthread_mutex_unlock(&conn->mta_conn_mutex);
-          }
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+          conn->mta_conn_mutex_lock_already = FALSE;
+          conn->mta_conn_mutex_unlock_later = FALSE;
+          SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+          pthread_mutex_unlock(&conn->mta_conn_mutex);
           if (
             share->monitoring_kind[roop_count2] &&
             spider->need_mons[roop_count2]
@@ -6274,15 +6293,12 @@ int spider_db_bulk_insert(
           {
             conn->db_conn->set_dup_key_idx(spider, roop_count2);
           }
-          conn->mta_conn_mutex_lock_already =
-            mta_conn_mutex_lock_already_backup;
-          conn->mta_conn_mutex_unlock_later =
-            mta_conn_mutex_unlock_later_backup;
-          if (!mta_conn_mutex_unlock_later_backup)
-          {
-            SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-            pthread_mutex_unlock(&conn->mta_conn_mutex);
-          }
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+          conn->mta_conn_mutex_lock_already = FALSE;
+          conn->mta_conn_mutex_unlock_later = FALSE;
+          SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+          pthread_mutex_unlock(&conn->mta_conn_mutex);
           if (
             error_num != ER_DUP_ENTRY &&
             error_num != ER_DUP_KEY &&
@@ -6309,8 +6325,10 @@ int spider_db_bulk_insert(
           }
           DBUG_RETURN(error_num);
         }
-        conn->mta_conn_mutex_lock_already = mta_conn_mutex_lock_already_backup;
-        conn->mta_conn_mutex_unlock_later = mta_conn_mutex_unlock_later_backup;
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+        conn->mta_conn_mutex_lock_already = FALSE;
+        conn->mta_conn_mutex_unlock_later = FALSE;
         if (!insert_info && copy_info)
         {
           insert_info =
@@ -6351,11 +6369,8 @@ int spider_db_bulk_insert(
           }
         }
 #endif
-        if (!mta_conn_mutex_unlock_later_backup)
-        {
-          SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-          pthread_mutex_unlock(&conn->mta_conn_mutex);
-        }
+        SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+        pthread_mutex_unlock(&conn->mta_conn_mutex);
         if (first_insert_link_idx == -1)
         {
           first_insert_link_idx = roop_count2;
@@ -6364,14 +6379,12 @@ int spider_db_bulk_insert(
       }
 
       conn = first_insert_conn;
-      mta_conn_mutex_lock_already_backup = conn->mta_conn_mutex_lock_already;
-      mta_conn_mutex_unlock_later_backup = conn->mta_conn_mutex_unlock_later;
-      if (!mta_conn_mutex_lock_already_backup)
-      {
-        pthread_mutex_lock(&conn->mta_conn_mutex);
-        SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
-      }
+      pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+      pthread_mutex_lock(&conn->mta_conn_mutex);
+      SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
       conn->need_mon = &spider->need_mons[first_insert_link_idx];
+      DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = TRUE;
       conn->mta_conn_mutex_unlock_later = TRUE;
       if (spider->sql_kinds & SPIDER_SQL_KIND_SQL)
@@ -6393,15 +6406,12 @@ int spider_db_bulk_insert(
         else if ((error_num = dbton_handler->
           show_last_insert_id(first_insert_link_idx, last_insert_id)))
         {
-          conn->mta_conn_mutex_lock_already =
-            mta_conn_mutex_lock_already_backup;
-          conn->mta_conn_mutex_unlock_later =
-            mta_conn_mutex_unlock_later_backup;
-          if (!mta_conn_mutex_unlock_later_backup)
-          {
-            SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-            pthread_mutex_unlock(&conn->mta_conn_mutex);
-          }
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+          conn->mta_conn_mutex_lock_already = FALSE;
+          conn->mta_conn_mutex_unlock_later = FALSE;
+          SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+          pthread_mutex_unlock(&conn->mta_conn_mutex);
           DBUG_RETURN(error_num);
         }
         table->next_number_field->set_notnull();
@@ -6411,25 +6421,21 @@ int spider_db_bulk_insert(
           (error_num = table->next_number_field->store(
             last_insert_id, TRUE))
         ) {
-          conn->mta_conn_mutex_lock_already =
-            mta_conn_mutex_lock_already_backup;
-          conn->mta_conn_mutex_unlock_later =
-            mta_conn_mutex_unlock_later_backup;
-          if (!mta_conn_mutex_unlock_later_backup)
-          {
-            SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-            pthread_mutex_unlock(&conn->mta_conn_mutex);
-          }
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+          conn->mta_conn_mutex_lock_already = FALSE;
+          conn->mta_conn_mutex_unlock_later = FALSE;
+          SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+          pthread_mutex_unlock(&conn->mta_conn_mutex);
           DBUG_RETURN(error_num);
         }
       }
-      conn->mta_conn_mutex_lock_already = mta_conn_mutex_lock_already_backup;
-      conn->mta_conn_mutex_unlock_later = mta_conn_mutex_unlock_later_backup;
-      if (!mta_conn_mutex_unlock_later_backup)
-      {
-        SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-        pthread_mutex_unlock(&conn->mta_conn_mutex);
-      }
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = FALSE;
+      conn->mta_conn_mutex_unlock_later = FALSE;
+      SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+      pthread_mutex_unlock(&conn->mta_conn_mutex);
       spider->store_last_insert_id = 0;
 #ifdef HA_CAN_BULK_ACCESS
     }
@@ -6473,8 +6479,11 @@ int spider_db_bulk_bulk_insert(
       conn = spider->hs_w_conns[roop_count2];
     }
 #endif
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
     pthread_mutex_lock(&conn->mta_conn_mutex);
     SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+    DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = TRUE;
     conn->mta_conn_mutex_unlock_later = TRUE;
     if ((tmp_error_num = spider_db_bulk_open_handler(spider, conn,
@@ -6482,6 +6491,8 @@ int spider_db_bulk_bulk_insert(
     {
       error_num = tmp_error_num;
     }
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
 #if defined(HS_HAS_SQLCOM) && defined(HAVE_HANDLERSOCKET)
@@ -6530,9 +6541,12 @@ int spider_db_bulk_bulk_insert(
   }
 
   conn = first_insert_conn;
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
   pthread_mutex_lock(&conn->mta_conn_mutex);
   SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
   conn->need_mon = &spider->need_mons[first_insert_link_idx];
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = TRUE;
   conn->mta_conn_mutex_unlock_later = TRUE;
   if (table->next_number_field &&
@@ -6559,6 +6573,8 @@ int spider_db_bulk_bulk_insert(
       error_num = tmp_error_num;
     }
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = FALSE;
   conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -6686,6 +6702,7 @@ int spider_db_bulk_update_size_limit(
     ) {
       conn = spider->conns[roop_count];
       spider_db_handler *dbton_hdl = spider->dbton_handler[conn->dbton_id];
+      pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
       if (dbton_hdl->need_lock_before_set_sql_for_exec(
         SPIDER_SQL_TYPE_BULK_UPDATE_SQL))
       {
@@ -6695,6 +6712,12 @@ int spider_db_bulk_update_size_limit(
       if ((error_num = dbton_hdl->set_sql_for_exec(
         SPIDER_SQL_TYPE_BULK_UPDATE_SQL, roop_count)))
       {
+        if (dbton_hdl->need_lock_before_set_sql_for_exec(
+          SPIDER_SQL_TYPE_BULK_UPDATE_SQL))
+        {
+          SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+          pthread_mutex_unlock(&conn->mta_conn_mutex);
+        }
         DBUG_RETURN(error_num);
       }
       if (!dbton_hdl->need_lock_before_set_sql_for_exec(
@@ -6705,7 +6728,11 @@ int spider_db_bulk_update_size_limit(
       }
       if ((error_num = spider_db_query_for_bulk_update(
         spider, conn, roop_count, &dup_key_found)))
+      {
+        pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
         DBUG_RETURN(error_num);
+      }
+      pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
     }
     spider->reset_sql_sql(SPIDER_SQL_TYPE_BULK_UPDATE_SQL);
   } else {
@@ -6771,6 +6798,7 @@ int spider_db_bulk_update_end(
         ) {
           conn = spider->conns[roop_count];
           spider_db_handler *dbton_hdl = spider->dbton_handler[conn->dbton_id];
+          pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
           if (dbton_hdl->need_lock_before_set_sql_for_exec(
             SPIDER_SQL_TYPE_BULK_UPDATE_SQL))
           {
@@ -6780,14 +6808,14 @@ int spider_db_bulk_update_end(
           if ((error_num = dbton_hdl->set_sql_for_exec(
             SPIDER_SQL_TYPE_BULK_UPDATE_SQL, roop_count)))
           {
+            if (dbton_hdl->need_lock_before_set_sql_for_exec(
+              SPIDER_SQL_TYPE_BULK_UPDATE_SQL))
+            {
+              SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+              pthread_mutex_unlock(&conn->mta_conn_mutex);
+            }
             if (error_num == ER_SPIDER_COND_SKIP_NUM)
             {
-              if (dbton_hdl->need_lock_before_set_sql_for_exec(
-                SPIDER_SQL_TYPE_BULK_UPDATE_SQL))
-              {
-                SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-                pthread_mutex_unlock(&conn->mta_conn_mutex);
-              }
               continue;
             }
             DBUG_RETURN(error_num);
@@ -6800,7 +6828,11 @@ int spider_db_bulk_update_end(
           }
           if ((error_num = spider_db_query_for_bulk_update(
             spider, conn, roop_count, dup_key_found)))
+          {
+            pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
             goto error_query;
+          }
+          pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
         }
       }
       if (error_num != HA_ERR_END_OF_FILE)
@@ -6825,6 +6857,7 @@ int spider_db_bulk_update_end(
       ) {
         conn = spider->conns[roop_count];
         spider_db_handler *dbton_hdl = spider->dbton_handler[conn->dbton_id];
+        pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
         if (dbton_hdl->need_lock_before_set_sql_for_exec(
           SPIDER_SQL_TYPE_BULK_UPDATE_SQL))
         {
@@ -6834,6 +6867,12 @@ int spider_db_bulk_update_end(
         if ((error_num = dbton_hdl->set_sql_for_exec(
           SPIDER_SQL_TYPE_BULK_UPDATE_SQL, roop_count)))
         {
+          if (dbton_hdl->need_lock_before_set_sql_for_exec(
+            SPIDER_SQL_TYPE_BULK_UPDATE_SQL))
+          {
+            SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+            pthread_mutex_unlock(&conn->mta_conn_mutex);
+          }
           DBUG_RETURN(error_num);
         }
         if (!dbton_hdl->need_lock_before_set_sql_for_exec(
@@ -6844,7 +6883,11 @@ int spider_db_bulk_update_end(
         }
         if ((error_num = spider_db_query_for_bulk_update(
           spider, conn, roop_count, dup_key_found)))
+        {
+          pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
           goto error_last_query;
+        }
+        pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
       }
     }
   }
@@ -6912,6 +6955,7 @@ int spider_db_update(
 #if defined(MARIADB_BASE_VERSION) && MYSQL_VERSION_ID >= 100000
     conn->ignore_dup_key = spider->ignore_dup_key;
 #endif
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
     if (dbton_hdl->need_lock_before_set_sql_for_exec(
       SPIDER_SQL_TYPE_UPDATE_SQL))
     {
@@ -6921,6 +6965,12 @@ int spider_db_update(
     if ((error_num = dbton_hdl->set_sql_for_exec(
       SPIDER_SQL_TYPE_UPDATE_SQL, roop_count)))
     {
+      if (dbton_hdl->need_lock_before_set_sql_for_exec(
+        SPIDER_SQL_TYPE_UPDATE_SQL))
+      {
+        SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+        pthread_mutex_unlock(&conn->mta_conn_mutex);
+      }
       DBUG_RETURN(error_num);
     }
     if (!dbton_hdl->need_lock_before_set_sql_for_exec(
@@ -6930,10 +6980,14 @@ int spider_db_update(
       SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
     }
     conn->need_mon = &spider->need_mons[roop_count];
+    DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = TRUE;
     conn->mta_conn_mutex_unlock_later = TRUE;
     if ((error_num = spider_db_set_names(spider, conn, roop_count)))
     {
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -6969,6 +7023,8 @@ int spider_db_update(
       -1,
       &spider->need_mons[roop_count])
     ) {
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       error_num = spider_db_errorno(conn);
@@ -7008,6 +7064,8 @@ int spider_db_update(
       if ((error_num = dbton_hdl->append_insert_for_recovery(
         SPIDER_SQL_TYPE_INSERT_SQL, roop_count)))
       {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -7022,6 +7080,8 @@ int spider_db_update(
         -1,
         &spider->need_mons[roop_count])
       ) {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         error_num = spider_db_errorno(conn);
@@ -7052,6 +7112,8 @@ int spider_db_update(
         DBUG_RETURN(error_num);
       }
     }
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -7242,6 +7304,7 @@ int spider_db_direct_update(
     }
 #endif
     spider_db_handler *dbton_hdl = spider->dbton_handler[conn->dbton_id];
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
     if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
     {
       pthread_mutex_lock(&conn->mta_conn_mutex);
@@ -7249,6 +7312,11 @@ int spider_db_direct_update(
     }
     if ((error_num = dbton_hdl->set_sql_for_exec(sql_type, roop_count)))
     {
+      if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
+      {
+        SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+        pthread_mutex_unlock(&conn->mta_conn_mutex);
+      }
       DBUG_RETURN(error_num);
     }
     if (!dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
@@ -7264,10 +7332,14 @@ int spider_db_direct_update(
     } else {
 #endif
       conn->need_mon = &spider->need_mons[roop_count];
+      DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = TRUE;
       conn->mta_conn_mutex_unlock_later = TRUE;
       if ((error_num = spider_db_set_names(spider, conn, roop_count)))
       {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -7306,6 +7378,8 @@ int spider_db_direct_update(
         ) &&
         (error_num != HA_ERR_FOUND_DUPP_KEY || !spider->ignore_dup_key)
       ) {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         error_num = spider_db_errorno(conn);
@@ -7377,6 +7451,8 @@ int spider_db_direct_update(
           {
             error_num = spider_db_errorno(conn);
           }
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -7385,11 +7461,13 @@ int spider_db_direct_update(
         }
       }
 #endif
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = FALSE;
+      conn->mta_conn_mutex_unlock_later = FALSE;
 #ifdef HA_CAN_BULK_ACCESS
     }
 #endif
-    conn->mta_conn_mutex_lock_already = FALSE;
-    conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
     pthread_mutex_unlock(&conn->mta_conn_mutex);
   }
@@ -7502,6 +7580,7 @@ int spider_db_direct_update(
     conn = spider->conns[roop_count];
     sql_type = SPIDER_SQL_TYPE_UPDATE_SQL;
     spider_db_handler *dbton_hdl = spider->dbton_handler[conn->dbton_id];
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
     if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
     {
       pthread_mutex_lock(&conn->mta_conn_mutex);
@@ -7509,6 +7588,11 @@ int spider_db_direct_update(
     }
     if ((error_num = dbton_hdl->set_sql_for_exec(sql_type, roop_count)))
     {
+      if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
+      {
+        SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+        pthread_mutex_unlock(&conn->mta_conn_mutex);
+      }
       DBUG_RETURN(error_num);
     }
     if (!dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
@@ -7524,10 +7608,14 @@ int spider_db_direct_update(
     } else {
 #endif
       conn->need_mon = &spider->need_mons[roop_count];
+      DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = TRUE;
       conn->mta_conn_mutex_unlock_later = TRUE;
       if ((error_num = spider_db_set_names(spider, conn, roop_count)))
       {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -7566,6 +7654,8 @@ int spider_db_direct_update(
         ) &&
         (error_num != HA_ERR_FOUND_DUPP_KEY || !spider->ignore_dup_key)
       ) {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         error_num = spider_db_errorno(conn);
@@ -7603,11 +7693,13 @@ int spider_db_direct_update(
         DBUG_PRINT("info", ("spider found_rows = %llu", *found_rows));
         counted = TRUE;
       }
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = FALSE;
+      conn->mta_conn_mutex_unlock_later = FALSE;
 #ifdef HA_CAN_BULK_ACCESS
     }
 #endif
-    conn->mta_conn_mutex_lock_already = FALSE;
-    conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
     pthread_mutex_unlock(&conn->mta_conn_mutex);
   }
@@ -7649,8 +7741,11 @@ int spider_db_bulk_direct_update(
       conn = spider->hs_w_conns[roop_count];
     }
 #endif
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
     pthread_mutex_lock(&conn->mta_conn_mutex);
     SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+    DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = TRUE;
     conn->mta_conn_mutex_unlock_later = TRUE;
     if ((tmp_error_num = spider_db_bulk_open_handler(spider, conn,
@@ -7700,6 +7795,8 @@ int spider_db_bulk_direct_update(
         {
           error_num = spider_db_errorno(conn);
         }
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -7708,6 +7805,8 @@ int spider_db_bulk_direct_update(
       }
     }
 #endif
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -7764,6 +7863,7 @@ int spider_db_delete(
   ) {
     conn = spider->conns[roop_count];
     spider_db_handler *dbton_hdl = spider->dbton_handler[conn->dbton_id];
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
     if (dbton_hdl->need_lock_before_set_sql_for_exec(
       SPIDER_SQL_TYPE_DELETE_SQL))
     {
@@ -7773,6 +7873,12 @@ int spider_db_delete(
     if ((error_num = dbton_hdl->set_sql_for_exec(
       SPIDER_SQL_TYPE_DELETE_SQL, roop_count)))
     {
+      if (dbton_hdl->need_lock_before_set_sql_for_exec(
+        SPIDER_SQL_TYPE_DELETE_SQL))
+      {
+        SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+        pthread_mutex_unlock(&conn->mta_conn_mutex);
+      }
       DBUG_RETURN(error_num);
     }
     if (!dbton_hdl->need_lock_before_set_sql_for_exec(
@@ -7781,9 +7887,27 @@ int spider_db_delete(
       pthread_mutex_lock(&conn->mta_conn_mutex);
       SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
     }
+    DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = TRUE;
+    conn->mta_conn_mutex_unlock_later = TRUE;
     if ((error_num = spider_db_query_with_set_names(
       SPIDER_SQL_TYPE_DELETE_SQL, spider, conn, roop_count)))
+    {
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = FALSE;
+      conn->mta_conn_mutex_unlock_later = FALSE;
+      SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+      pthread_mutex_unlock(&conn->mta_conn_mutex);
       DBUG_RETURN(error_num);
+    }
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = FALSE;
+    conn->mta_conn_mutex_unlock_later = FALSE;
+    SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+    pthread_mutex_unlock(&conn->mta_conn_mutex);
     result_list->update_sqls[roop_count].length(0);
   }
   if ((error_num = spider->reset_sql_sql(SPIDER_SQL_TYPE_DELETE_SQL)))
@@ -7896,6 +8020,7 @@ int spider_db_direct_delete(
     }
 #endif
     spider_db_handler *dbton_hdl = spider->dbton_handler[conn->dbton_id];
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
     if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
     {
       pthread_mutex_lock(&conn->mta_conn_mutex);
@@ -7903,6 +8028,11 @@ int spider_db_direct_delete(
     }
     if ((error_num = dbton_hdl->set_sql_for_exec(sql_type, roop_count)))
     {
+      if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
+      {
+        SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+        pthread_mutex_unlock(&conn->mta_conn_mutex);
+      }
       DBUG_RETURN(error_num);
     }
     if (!dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
@@ -7918,10 +8048,14 @@ int spider_db_direct_delete(
     } else {
 #endif
       conn->need_mon = &spider->need_mons[roop_count];
+      DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = TRUE;
       conn->mta_conn_mutex_unlock_later = TRUE;
       if ((error_num = spider_db_set_names(spider, conn, roop_count)))
       {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -7957,6 +8091,8 @@ int spider_db_direct_delete(
         -1,
         &spider->need_mons[roop_count])
       ) {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         error_num = spider_db_errorno(conn);
@@ -7983,6 +8119,8 @@ int spider_db_direct_delete(
         }
         DBUG_RETURN(error_num);
       }
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
 #if defined(HS_HAS_SQLCOM) && defined(HAVE_HANDLERSOCKET)
@@ -8118,6 +8256,7 @@ int spider_db_direct_delete(
     conn = spider->conns[roop_count];
     sql_type = SPIDER_SQL_TYPE_DELETE_SQL;
     spider_db_handler *dbton_hdl = spider->dbton_handler[conn->dbton_id];
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
     if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
     {
       pthread_mutex_lock(&conn->mta_conn_mutex);
@@ -8125,6 +8264,11 @@ int spider_db_direct_delete(
     }
     if ((error_num = dbton_hdl->set_sql_for_exec(sql_type, roop_count)))
     {
+      if (dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
+      {
+        SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+        pthread_mutex_unlock(&conn->mta_conn_mutex);
+      }
       DBUG_RETURN(error_num);
     }
     if (!dbton_hdl->need_lock_before_set_sql_for_exec(sql_type))
@@ -8140,10 +8284,14 @@ int spider_db_direct_delete(
     } else {
 #endif
       conn->need_mon = &spider->need_mons[roop_count];
+      DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = TRUE;
       conn->mta_conn_mutex_unlock_later = TRUE;
       if ((error_num = spider_db_set_names(spider, conn, roop_count)))
       {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -8179,6 +8327,8 @@ int spider_db_direct_delete(
         -1,
         &spider->need_mons[roop_count])
       ) {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         error_num = spider_db_errorno(conn);
@@ -8205,6 +8355,8 @@ int spider_db_direct_delete(
         }
         DBUG_RETURN(error_num);
       }
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       if (!counted)
@@ -8253,6 +8405,7 @@ int spider_db_delete_all_rows(
     uint dbton_id = share->use_sql_dbton_ids[roop_count];
     spider_db_handler *dbton_hdl = spider->dbton_handler[dbton_id];
     conn = spider->conns[roop_count];
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
     if (dbton_hdl->need_lock_before_set_sql_for_exec(
       SPIDER_SQL_TYPE_DELETE_SQL))
     {
@@ -8262,6 +8415,12 @@ int spider_db_delete_all_rows(
     if ((error_num = dbton_hdl->set_sql_for_exec(
       SPIDER_SQL_TYPE_DELETE_SQL, roop_count)))
     {
+      if (dbton_hdl->need_lock_before_set_sql_for_exec(
+        SPIDER_SQL_TYPE_DELETE_SQL))
+      {
+        SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+        pthread_mutex_unlock(&conn->mta_conn_mutex);
+      }
       DBUG_RETURN(error_num);
     }
     if (!dbton_hdl->need_lock_before_set_sql_for_exec(
@@ -8271,6 +8430,8 @@ int spider_db_delete_all_rows(
       SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
     }
     conn->need_mon = &spider->need_mons[roop_count];
+    DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = TRUE;
     conn->mta_conn_mutex_unlock_later = TRUE;
     spider_conn_set_timeout_from_share(conn, roop_count, spider->trx->thd,
@@ -8293,6 +8454,8 @@ int spider_db_delete_all_rows(
         /* retry */
         if ((error_num = spider_db_ping(spider, conn, roop_count)))
         {
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -8322,6 +8485,8 @@ int spider_db_delete_all_rows(
         }
         if ((error_num = spider_db_set_names(spider, conn, roop_count)))
         {
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -8357,6 +8522,8 @@ int spider_db_delete_all_rows(
           -1,
           &spider->need_mons[roop_count])
         ) {
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           error_num = spider_db_errorno(conn);
@@ -8384,6 +8551,8 @@ int spider_db_delete_all_rows(
           DBUG_RETURN(error_num);
         }
       } else {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -8412,6 +8581,8 @@ int spider_db_delete_all_rows(
         DBUG_RETURN(error_num);
       }
     }
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -10257,7 +10428,14 @@ int spider_db_udf_direct_sql(
   c_thd->lex->sql_command = SQLCOM_INSERT;
 #endif
 
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+  pthread_mutex_lock(&conn->mta_conn_mutex);
+  SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
   conn->need_mon = &need_mon;
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = TRUE;
+  conn->mta_conn_mutex_unlock_later = TRUE;
   if (
     !(error_num = spider_db_udf_direct_sql_set_names(direct_sql, trx, conn)) &&
     !(error_num = spider_db_udf_direct_sql_select_db(direct_sql, conn))
@@ -10280,9 +10458,6 @@ int spider_db_udf_direct_sql(
 #endif
         DBUG_RETURN(error_num);
       }
-      pthread_mutex_lock(&conn->mta_conn_mutex);
-      SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
-      DBUG_ASSERT(conn->mta_conn_mutex_file_pos.file_name);
     }
 #endif
     spider_conn_set_timeout_from_direct_sql(conn, thd, direct_sql);
@@ -10301,8 +10476,6 @@ int spider_db_udf_direct_sql(
       DBUG_PRINT("info",("spider conn=%p", conn));
       if (!direct_sql->table_count)
         roop_count = -1;
-      conn->mta_conn_mutex_lock_already = TRUE;
-      conn->mta_conn_mutex_unlock_later = TRUE;
       do {
         if (roop_count == direct_sql->table_count)
         {
@@ -10514,12 +10687,14 @@ int spider_db_udf_direct_sql(
         if (roop_count >= 0)
           roop_count++;
       } while (status == 0);
-      conn->mta_conn_mutex_lock_already = FALSE;
-      conn->mta_conn_mutex_unlock_later = FALSE;
-      SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-      pthread_mutex_unlock(&conn->mta_conn_mutex);
     }
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = FALSE;
+  conn->mta_conn_mutex_unlock_later = FALSE;
+  SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+  pthread_mutex_unlock(&conn->mta_conn_mutex);
   if (need_trx_end && insert_start)
   {
     if (error_num)
@@ -10549,19 +10724,13 @@ int spider_db_udf_direct_sql_select_db(
   SPIDER_CONN *conn
 ) {
   int error_num, need_mon = 0;
-  bool tmp_mta_conn_mutex_lock_already;
   SPIDER_DB_CONN *db_conn = conn->db_conn;
   DBUG_ENTER("spider_db_udf_direct_sql_select_db");
+  pthread_mutex_assert_owner(&conn->mta_conn_mutex);
 #if defined(HS_HAS_SQLCOM) && defined(HAVE_HANDLERSOCKET)
   if (direct_sql->access_mode == 0)
   {
 #endif
-    if (!conn->mta_conn_mutex_lock_already)
-    {
-      pthread_mutex_lock(&conn->mta_conn_mutex);
-      SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
-      conn->need_mon = &need_mon;
-    }
     DBUG_ASSERT(conn->mta_conn_mutex_file_pos.file_name);
     if (
       !conn->default_database.length() ||
@@ -10570,8 +10739,6 @@ int spider_db_udf_direct_sql_select_db(
       memcmp(direct_sql->tgt_default_db_name, conn->default_database.ptr(),
         direct_sql->tgt_default_db_name_length)
     ) {
-      tmp_mta_conn_mutex_lock_already = conn->mta_conn_mutex_lock_already;
-      conn->mta_conn_mutex_lock_already = TRUE;
       if (
         (
           spider_db_before_query(conn, &need_mon) ||
@@ -10585,7 +10752,6 @@ int spider_db_udf_direct_sql_select_db(
         )
           my_message(ER_SPIDER_REMOTE_SERVER_GONE_AWAY_NUM,
             ER_SPIDER_REMOTE_SERVER_GONE_AWAY_STR, MYF(0));
-        conn->mta_conn_mutex_lock_already = tmp_mta_conn_mutex_lock_already;
         DBUG_RETURN(error_num);
       }
       conn->default_database.length(0);
@@ -10595,12 +10761,6 @@ int spider_db_udf_direct_sql_select_db(
       conn->default_database.q_append(direct_sql->tgt_default_db_name,
         direct_sql->tgt_default_db_name_length + 1);
       conn->default_database.length(direct_sql->tgt_default_db_name_length);
-      conn->mta_conn_mutex_lock_already = tmp_mta_conn_mutex_lock_already;
-    }
-    if (!conn->mta_conn_mutex_unlock_later)
-    {
-      SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-      pthread_mutex_unlock(&conn->mta_conn_mutex);
     }
 #if defined(HS_HAS_SQLCOM) && defined(HAVE_HANDLERSOCKET)
   }
@@ -10614,25 +10774,17 @@ int spider_db_udf_direct_sql_set_names(
   SPIDER_CONN *conn
 ) {
   int error_num, need_mon = 0;
-  bool tmp_mta_conn_mutex_lock_already;
   DBUG_ENTER("spider_db_udf_direct_sql_set_names");
+  pthread_mutex_assert_owner(&conn->mta_conn_mutex);
 #if defined(HS_HAS_SQLCOM) && defined(HAVE_HANDLERSOCKET)
   if (direct_sql->access_mode == 0)
   {
 #endif
-    if (!conn->mta_conn_mutex_lock_already)
-    {
-      pthread_mutex_lock(&conn->mta_conn_mutex);
-      SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
-      conn->need_mon = &need_mon;
-    }
     DBUG_ASSERT(conn->mta_conn_mutex_file_pos.file_name);
     if (
       !conn->access_charset ||
       trx->udf_access_charset->cset != conn->access_charset->cset
     ) {
-      tmp_mta_conn_mutex_lock_already = conn->mta_conn_mutex_lock_already;
-      conn->mta_conn_mutex_lock_already = TRUE;
       if (
         (
           spider_db_before_query(conn, &need_mon) ||
@@ -10647,17 +10799,10 @@ int spider_db_udf_direct_sql_set_names(
           my_message(ER_SPIDER_REMOTE_SERVER_GONE_AWAY_NUM,
             ER_SPIDER_REMOTE_SERVER_GONE_AWAY_STR, MYF(0));
         }
-        conn->mta_conn_mutex_lock_already = tmp_mta_conn_mutex_lock_already;
         DBUG_RETURN(error_num);
       }
-      conn->mta_conn_mutex_lock_already = tmp_mta_conn_mutex_lock_already;
       conn->access_charset = trx->udf_access_charset;
     }
-    if (!conn->mta_conn_mutex_unlock_later)
-    {
-      SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-      pthread_mutex_unlock(&conn->mta_conn_mutex);
-    }
 #if defined(HS_HAS_SQLCOM) && defined(HAVE_HANDLERSOCKET)
   }
 #endif
@@ -10721,13 +10866,18 @@ int spider_db_udf_ping_table(
     spider.conn_link_idx = &tmp_conn_link_idx;
     spider.db_request_phase = &db_request_phase;
     spider.db_request_id = &db_request_id;
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
     pthread_mutex_lock(&conn->mta_conn_mutex);
     SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
     conn->need_mon = &need_mon;
+    DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = TRUE;
     conn->mta_conn_mutex_unlock_later = TRUE;
     if ((error_num = spider_db_ping(&spider, conn, 0)))
     {
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -10743,6 +10893,8 @@ int spider_db_udf_ping_table(
         share->server_names[0]);
       DBUG_RETURN(ER_CONNECT_TO_FOREIGN_DATA_SOURCE);
     }
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -10789,13 +10941,18 @@ int spider_db_udf_ping_table(
         my_afree(sql_buf);
         DBUG_RETURN(error_num);
       }
+      pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
       pthread_mutex_lock(&conn->mta_conn_mutex);
       SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
       conn->need_mon = &need_mon;
+      DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = TRUE;
       conn->mta_conn_mutex_unlock_later = TRUE;
       if ((error_num = spider_db_set_names(&spider, conn, 0)))
       {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -10814,6 +10971,8 @@ int spider_db_udf_ping_table(
         -1,
         &need_mon)
       ) {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         error_num = spider_db_errorno(conn);
@@ -10823,6 +10982,8 @@ int spider_db_udf_ping_table(
         my_afree(sql_buf);
         DBUG_RETURN(error_num);
       }
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       spider_db_discard_result(&spider, 0, conn);
@@ -11028,13 +11189,18 @@ int spider_db_udf_ping_table_mon_next(
     DBUG_RETURN(error_num);
   }
 
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
   pthread_mutex_lock(&conn->mta_conn_mutex);
   SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
   conn->need_mon = &need_mon;
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = TRUE;
   conn->mta_conn_mutex_unlock_later = TRUE;
   if ((error_num = spider_db_ping(&spider, conn, 0)))
   {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -11046,6 +11212,8 @@ int spider_db_udf_ping_table_mon_next(
   }
   if ((error_num = spider_db_set_names(&spider, conn, 0)))
   {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -11061,6 +11229,8 @@ int spider_db_udf_ping_table_mon_next(
     -1,
     &need_mon)
   ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     my_afree(sql_buf);
@@ -11074,9 +11244,18 @@ int spider_db_udf_ping_table_mon_next(
   request_key.next = NULL;
   if (!(res = conn->db_conn->store_result(NULL, &request_key, &error_num)))
   {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
-    if (error_num || (error_num = spider_db_errorno(conn)))
+    if (error_num)
+    {
+      SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+      pthread_mutex_unlock(&conn->mta_conn_mutex);
+      my_afree(sql_buf);
+      DBUG_RETURN(error_num);
+    }
+    else if ((error_num = spider_db_errorno(conn)))
     {
       my_afree(sql_buf);
       DBUG_RETURN(error_num);
@@ -11085,6 +11264,8 @@ int spider_db_udf_ping_table_mon_next(
     my_afree(sql_buf);
     DBUG_RETURN(HA_ERR_OUT_OF_MEM);
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = FALSE;
   conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -11171,8 +11352,22 @@ int spider_db_udf_copy_tables(
         spider_conn_clear_queue_at_commit(tmp_conn);
         if (!tmp_conn->trx_start)
         {
+          pthread_mutex_assert_not_owner(&tmp_conn->mta_conn_mutex);
+          pthread_mutex_lock(&tmp_conn->mta_conn_mutex);
+          SPIDER_SET_FILE_POS(&tmp_conn->mta_conn_mutex_file_pos);
+          tmp_conn->need_mon = &tmp_spider->need_mons[0];
+          DBUG_ASSERT(!tmp_conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(!tmp_conn->mta_conn_mutex_unlock_later);
+          tmp_conn->mta_conn_mutex_lock_already = TRUE;
+          tmp_conn->mta_conn_mutex_unlock_later = TRUE;
           if (spider_db_ping(tmp_spider, tmp_conn, 0))
           {
+            DBUG_ASSERT(tmp_conn->mta_conn_mutex_lock_already);
+            DBUG_ASSERT(tmp_conn->mta_conn_mutex_unlock_later);
+            tmp_conn->mta_conn_mutex_lock_already = FALSE;
+            tmp_conn->mta_conn_mutex_unlock_later = FALSE;
+            SPIDER_CLEAR_FILE_POS(&tmp_conn->mta_conn_mutex_file_pos);
+            pthread_mutex_unlock(&tmp_conn->mta_conn_mutex);
             my_error(ER_CONNECT_TO_FOREIGN_DATA_SOURCE, MYF(0),
               tmp_spider->share->server_names[0]);
             error_num = ER_CONNECT_TO_FOREIGN_DATA_SOURCE;
@@ -11182,8 +11377,21 @@ int spider_db_udf_copy_tables(
             (error_num = spider_db_set_names(tmp_spider, tmp_conn, 0)) ||
             (error_num = spider_db_start_transaction(tmp_conn,
               tmp_spider->need_mons))
-          )
+          ) {
+            DBUG_ASSERT(tmp_conn->mta_conn_mutex_lock_already);
+            DBUG_ASSERT(tmp_conn->mta_conn_mutex_unlock_later);
+            tmp_conn->mta_conn_mutex_lock_already = FALSE;
+            tmp_conn->mta_conn_mutex_unlock_later = FALSE;
+            SPIDER_CLEAR_FILE_POS(&tmp_conn->mta_conn_mutex_file_pos);
+            pthread_mutex_unlock(&tmp_conn->mta_conn_mutex);
             goto error_start_transaction;
+          }
+          DBUG_ASSERT(tmp_conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(tmp_conn->mta_conn_mutex_unlock_later);
+          tmp_conn->mta_conn_mutex_lock_already = FALSE;
+          tmp_conn->mta_conn_mutex_unlock_later = FALSE;
+          SPIDER_CLEAR_FILE_POS(&tmp_conn->mta_conn_mutex_file_pos);
+          pthread_mutex_unlock(&tmp_conn->mta_conn_mutex);
         }
       }
     } else {
@@ -11203,8 +11411,22 @@ int spider_db_udf_copy_tables(
       {
         tmp_spider = &spider[roop_count];
         tmp_conn = tmp_spider->conns[0];
+        pthread_mutex_assert_not_owner(&tmp_conn->mta_conn_mutex);
+        pthread_mutex_lock(&tmp_conn->mta_conn_mutex);
+        SPIDER_SET_FILE_POS(&tmp_conn->mta_conn_mutex_file_pos);
+        tmp_conn->need_mon = &tmp_spider->need_mons[0];
+        DBUG_ASSERT(!tmp_conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(!tmp_conn->mta_conn_mutex_unlock_later);
+        tmp_conn->mta_conn_mutex_lock_already = TRUE;
+        tmp_conn->mta_conn_mutex_unlock_later = TRUE;
         if (spider_db_ping(tmp_spider, tmp_conn, 0))
         {
+          DBUG_ASSERT(tmp_conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(tmp_conn->mta_conn_mutex_unlock_later);
+          tmp_conn->mta_conn_mutex_lock_already = FALSE;
+          tmp_conn->mta_conn_mutex_unlock_later = FALSE;
+          SPIDER_CLEAR_FILE_POS(&tmp_conn->mta_conn_mutex_file_pos);
+          pthread_mutex_unlock(&tmp_conn->mta_conn_mutex);
           my_error(ER_CONNECT_TO_FOREIGN_DATA_SOURCE, MYF(0),
             tmp_spider->share->server_names[0]);
           error_num = ER_CONNECT_TO_FOREIGN_DATA_SOURCE;
@@ -11217,11 +11439,23 @@ int spider_db_udf_copy_tables(
             (error_num = spider_db_lock_tables(tmp_spider, 0))
           )
         ) {
+          DBUG_ASSERT(tmp_conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(tmp_conn->mta_conn_mutex_unlock_later);
+          tmp_conn->mta_conn_mutex_lock_already = FALSE;
+          tmp_conn->mta_conn_mutex_unlock_later = FALSE;
+          SPIDER_CLEAR_FILE_POS(&tmp_conn->mta_conn_mutex_file_pos);
+          pthread_mutex_unlock(&tmp_conn->mta_conn_mutex);
           tmp_conn->table_lock = 0;
           if (error_num == HA_ERR_OUT_OF_MEM)
             my_error(ER_OUT_OF_RESOURCES, MYF(0), HA_ERR_OUT_OF_MEM);
           goto error_lock_tables;
         }
+        DBUG_ASSERT(tmp_conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(tmp_conn->mta_conn_mutex_unlock_later);
+        tmp_conn->mta_conn_mutex_lock_already = FALSE;
+        tmp_conn->mta_conn_mutex_unlock_later = FALSE;
+        SPIDER_CLEAR_FILE_POS(&tmp_conn->mta_conn_mutex_file_pos);
+        pthread_mutex_unlock(&tmp_conn->mta_conn_mutex);
         tmp_conn->table_lock = 1;
       }
     }
@@ -11229,11 +11463,23 @@ int spider_db_udf_copy_tables(
     tmp_conn = src_tbl_conn->conn;
     spider_conn_set_timeout_from_share(tmp_conn, 0,
       copy_tables->trx->thd, src_tbl_conn->share);
+    pthread_mutex_assert_not_owner(&tmp_conn->mta_conn_mutex);
+    pthread_mutex_lock(&tmp_conn->mta_conn_mutex);
+    SPIDER_SET_FILE_POS(&tmp_conn->mta_conn_mutex_file_pos);
+    tmp_conn->need_mon = &src_tbl_conn->need_mon;
+    DBUG_ASSERT(!tmp_conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(!tmp_conn->mta_conn_mutex_unlock_later);
+    tmp_conn->mta_conn_mutex_lock_already = TRUE;
+    tmp_conn->mta_conn_mutex_unlock_later = TRUE;
     if (select_ct->exec_query(
       tmp_conn,
       -1,
       &src_tbl_conn->need_mon)
     ) {
+      DBUG_ASSERT(tmp_conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(tmp_conn->mta_conn_mutex_unlock_later);
+      tmp_conn->mta_conn_mutex_lock_already = FALSE;
+      tmp_conn->mta_conn_mutex_unlock_later = FALSE;
       error_num = spider_db_errorno(tmp_conn);
       if (error_num == ER_SPIDER_REMOTE_SERVER_GONE_AWAY_NUM)
         my_message(ER_SPIDER_REMOTE_SERVER_GONE_AWAY_NUM,
@@ -11262,6 +11508,10 @@ int spider_db_udf_copy_tables(
               my_error(ER_OUT_OF_RESOURCES, MYF(0), HA_ERR_OUT_OF_MEM);
             result->free_result();
             delete result;
+            DBUG_ASSERT(tmp_conn->mta_conn_mutex_lock_already);
+            DBUG_ASSERT(tmp_conn->mta_conn_mutex_unlock_later);
+            tmp_conn->mta_conn_mutex_lock_already = FALSE;
+            tmp_conn->mta_conn_mutex_unlock_later = FALSE;
             SPIDER_CLEAR_FILE_POS(&tmp_conn->mta_conn_mutex_file_pos);
             pthread_mutex_unlock(&tmp_conn->mta_conn_mutex);
             goto error_db_query;
@@ -11277,6 +11527,10 @@ int spider_db_udf_copy_tables(
                 my_error(ER_OUT_OF_RESOURCES, MYF(0), HA_ERR_OUT_OF_MEM);
               result->free_result();
               delete result;
+              DBUG_ASSERT(tmp_conn->mta_conn_mutex_lock_already);
+              DBUG_ASSERT(tmp_conn->mta_conn_mutex_unlock_later);
+              tmp_conn->mta_conn_mutex_lock_already = FALSE;
+              tmp_conn->mta_conn_mutex_unlock_later = FALSE;
               SPIDER_CLEAR_FILE_POS(&tmp_conn->mta_conn_mutex_file_pos);
               pthread_mutex_unlock(&tmp_conn->mta_conn_mutex);
               goto error_db_query;
@@ -11303,6 +11557,10 @@ int spider_db_udf_copy_tables(
                 my_error(ER_OUT_OF_RESOURCES, MYF(0), HA_ERR_OUT_OF_MEM);
               result->free_result();
               delete result;
+              DBUG_ASSERT(tmp_conn->mta_conn_mutex_lock_already);
+              DBUG_ASSERT(tmp_conn->mta_conn_mutex_unlock_later);
+              tmp_conn->mta_conn_mutex_lock_already = FALSE;
+              tmp_conn->mta_conn_mutex_unlock_later = FALSE;
               SPIDER_CLEAR_FILE_POS(&tmp_conn->mta_conn_mutex_file_pos);
               pthread_mutex_unlock(&tmp_conn->mta_conn_mutex);
               goto error_db_query;
@@ -11320,6 +11578,10 @@ int spider_db_udf_copy_tables(
               my_error(ER_OUT_OF_RESOURCES, MYF(0), HA_ERR_OUT_OF_MEM);
               result->free_result();
               delete result;
+              DBUG_ASSERT(tmp_conn->mta_conn_mutex_lock_already);
+              DBUG_ASSERT(tmp_conn->mta_conn_mutex_unlock_later);
+              tmp_conn->mta_conn_mutex_lock_already = FALSE;
+              tmp_conn->mta_conn_mutex_unlock_later = FALSE;
               SPIDER_CLEAR_FILE_POS(&tmp_conn->mta_conn_mutex_file_pos);
               pthread_mutex_unlock(&tmp_conn->mta_conn_mutex);
               error_num = ER_OUT_OF_RESOURCES;
@@ -11332,12 +11594,20 @@ int spider_db_udf_copy_tables(
             my_error(ER_OUT_OF_RESOURCES, MYF(0), HA_ERR_OUT_OF_MEM);
           result->free_result();
           delete result;
+          DBUG_ASSERT(tmp_conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(tmp_conn->mta_conn_mutex_unlock_later);
+          tmp_conn->mta_conn_mutex_lock_already = FALSE;
+          tmp_conn->mta_conn_mutex_unlock_later = FALSE;
           SPIDER_CLEAR_FILE_POS(&tmp_conn->mta_conn_mutex_file_pos);
           pthread_mutex_unlock(&tmp_conn->mta_conn_mutex);
           goto error_db_query;
         }
         result->free_result();
         delete result;
+        DBUG_ASSERT(tmp_conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(tmp_conn->mta_conn_mutex_unlock_later);
+        tmp_conn->mta_conn_mutex_lock_already = FALSE;
+        tmp_conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&tmp_conn->mta_conn_mutex_file_pos);
         pthread_mutex_unlock(&tmp_conn->mta_conn_mutex);
         for (dst_tbl_conn = copy_tables->table_conn[1]; dst_tbl_conn;
@@ -11358,6 +11628,12 @@ int spider_db_udf_copy_tables(
         }
         if (error_num)
         {
+          DBUG_ASSERT(tmp_conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(tmp_conn->mta_conn_mutex_unlock_later);
+          tmp_conn->mta_conn_mutex_lock_already = FALSE;
+          tmp_conn->mta_conn_mutex_unlock_later = FALSE;
+          SPIDER_CLEAR_FILE_POS(&tmp_conn->mta_conn_mutex_file_pos);
+          pthread_mutex_unlock(&tmp_conn->mta_conn_mutex);
           if (error_num == ER_SPIDER_REMOTE_SERVER_GONE_AWAY_NUM)
             my_message(ER_SPIDER_REMOTE_SERVER_GONE_AWAY_NUM,
               ER_SPIDER_REMOTE_SERVER_GONE_AWAY_STR, MYF(0));
@@ -11365,6 +11641,10 @@ int spider_db_udf_copy_tables(
         }
         error_num = HA_ERR_END_OF_FILE;
         end_of_file = TRUE;
+        DBUG_ASSERT(tmp_conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(tmp_conn->mta_conn_mutex_unlock_later);
+        tmp_conn->mta_conn_mutex_lock_already = FALSE;
+        tmp_conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&tmp_conn->mta_conn_mutex_file_pos);
         pthread_mutex_unlock(&tmp_conn->mta_conn_mutex);
       }
@@ -11407,9 +11687,12 @@ int spider_db_udf_copy_tables(
         {
           tmp_conn = dst_tbl_conn->conn;
           insert_ct = dst_tbl_conn->copy_table;
+          pthread_mutex_assert_not_owner(&tmp_conn->mta_conn_mutex);
           pthread_mutex_lock(&tmp_conn->mta_conn_mutex);
           SPIDER_SET_FILE_POS(&tmp_conn->mta_conn_mutex_file_pos);
           tmp_conn->need_mon = &dst_tbl_conn->need_mon;
+          DBUG_ASSERT(!tmp_conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(!tmp_conn->mta_conn_mutex_unlock_later);
           tmp_conn->mta_conn_mutex_lock_already = TRUE;
           tmp_conn->mta_conn_mutex_unlock_later = TRUE;
           spider_conn_set_timeout_from_share(tmp_conn, 0,
@@ -11419,6 +11702,8 @@ int spider_db_udf_copy_tables(
             -1,
             &dst_tbl_conn->need_mon)
           ) {
+            DBUG_ASSERT(tmp_conn->mta_conn_mutex_lock_already);
+            DBUG_ASSERT(tmp_conn->mta_conn_mutex_unlock_later);
             tmp_conn->mta_conn_mutex_lock_already = FALSE;
             tmp_conn->mta_conn_mutex_unlock_later = FALSE;
             error_num = spider_db_errorno(tmp_conn);
@@ -11427,6 +11712,8 @@ int spider_db_udf_copy_tables(
                 ER_SPIDER_REMOTE_SERVER_GONE_AWAY_STR, MYF(0));
             goto error_db_query;
           } else {
+            DBUG_ASSERT(tmp_conn->mta_conn_mutex_lock_already);
+            DBUG_ASSERT(tmp_conn->mta_conn_mutex_unlock_later);
             tmp_conn->mta_conn_mutex_lock_already = FALSE;
             tmp_conn->mta_conn_mutex_unlock_later = FALSE;
             SPIDER_CLEAR_FILE_POS(&tmp_conn->mta_conn_mutex_file_pos);
@@ -11567,8 +11854,6 @@ int spider_db_open_handler(
   int link_idx
 ) {
   int error_num;
-  bool tmp_mta_conn_mutex_lock_already;
-  bool tmp_mta_conn_mutex_unlock_later;
   SPIDER_SHARE *share = spider->share;
   uint *handler_id_ptr =
 #if defined(HS_HAS_SQLCOM) && defined(HAVE_HANDLERSOCKET)
@@ -11583,16 +11868,14 @@ int spider_db_open_handler(
     ;
   spider_db_handler *dbton_hdl = spider->dbton_handler[conn->dbton_id];
   DBUG_ENTER("spider_db_open_handler");
-  if (!conn->mta_conn_mutex_lock_already)
-  {
-    pthread_mutex_lock(&conn->mta_conn_mutex);
-    SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
-    conn->need_mon = &spider->need_mons[link_idx];
-  }
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+  pthread_mutex_lock(&conn->mta_conn_mutex);
+  SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+  conn->need_mon = &spider->need_mons[link_idx];
   DBUG_ASSERT(conn->mta_conn_mutex_file_pos.file_name);
-  tmp_mta_conn_mutex_lock_already = conn->mta_conn_mutex_lock_already;
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = TRUE;
-  tmp_mta_conn_mutex_unlock_later = conn->mta_conn_mutex_unlock_later;
   conn->mta_conn_mutex_unlock_later = TRUE;
   if (!spider->handler_opened(link_idx, conn->conn_kind))
     *handler_id_ptr = conn->opened_handlers;
@@ -11641,11 +11924,6 @@ int spider_db_open_handler(
       {
         my_printf_error(ER_SPIDER_HS_NUM, ER_SPIDER_HS_STR, MYF(0),
           conn->db_conn->get_errno(), conn->db_conn->get_error());
-        if (!conn->mta_conn_mutex_unlock_later)
-        {
-          SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-          pthread_mutex_unlock(&conn->mta_conn_mutex);
-        }
         spider->need_mons[link_idx] = ER_SPIDER_HS_NUM;
         error_num = ER_SPIDER_HS_NUM;
         goto error;
@@ -11781,23 +12059,21 @@ int spider_db_open_handler(
   }
   DBUG_PRINT("info",("spider conn=%p", conn));
   DBUG_PRINT("info",("spider opened_handlers=%u", conn->opened_handlers));
-  conn->mta_conn_mutex_lock_already = tmp_mta_conn_mutex_lock_already;
-  conn->mta_conn_mutex_unlock_later = tmp_mta_conn_mutex_unlock_later;
-  if (!tmp_mta_conn_mutex_unlock_later)
-  {
-    SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-    pthread_mutex_unlock(&conn->mta_conn_mutex);
-  }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = FALSE;
+  conn->mta_conn_mutex_unlock_later = FALSE;
+  SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+  pthread_mutex_unlock(&conn->mta_conn_mutex);
   DBUG_RETURN(0);
 
 error:
-  conn->mta_conn_mutex_lock_already = tmp_mta_conn_mutex_lock_already;
-  conn->mta_conn_mutex_unlock_later = tmp_mta_conn_mutex_unlock_later;
-  if (!tmp_mta_conn_mutex_unlock_later)
-  {
-    SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-    pthread_mutex_unlock(&conn->mta_conn_mutex);
-  }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = FALSE;
+  conn->mta_conn_mutex_unlock_later = FALSE;
+  SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+  pthread_mutex_unlock(&conn->mta_conn_mutex);
   DBUG_RETURN(error_num);
 }
 
@@ -11847,6 +12123,7 @@ int spider_db_bulk_open_handler(
     }
 
     bool tmp_mta_conn_mutex_unlock_later;
+    pthread_mutex_assert_owner(&conn->mta_conn_mutex);
     tmp_mta_conn_mutex_unlock_later = conn->mta_conn_mutex_unlock_later;
     conn->mta_conn_mutex_unlock_later = TRUE;
     SPIDER_DB_RESULT *result;
@@ -11885,24 +12162,19 @@ int spider_db_close_handler(
   uint tgt_conn_kind
 ) {
   int error_num;
-  bool tmp_mta_conn_mutex_lock_already;
-  bool tmp_mta_conn_mutex_unlock_later;
   spider_db_handler *dbton_hdl = spider->dbton_handler[conn->dbton_id];
   DBUG_ENTER("spider_db_close_handler");
   DBUG_PRINT("info",("spider conn=%p", conn));
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+  pthread_mutex_lock(&conn->mta_conn_mutex);
+  SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+  conn->need_mon = &spider->need_mons[link_idx];
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = TRUE;
+  conn->mta_conn_mutex_unlock_later = TRUE;
   if (spider->handler_opened(link_idx, tgt_conn_kind))
   {
-    if (!conn->mta_conn_mutex_lock_already)
-    {
-      pthread_mutex_lock(&conn->mta_conn_mutex);
-      SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
-      conn->need_mon = &spider->need_mons[link_idx];
-    }
-    DBUG_ASSERT(conn->mta_conn_mutex_file_pos.file_name);
-    tmp_mta_conn_mutex_lock_already = conn->mta_conn_mutex_lock_already;
-    conn->mta_conn_mutex_lock_already = TRUE;
-    tmp_mta_conn_mutex_unlock_later = conn->mta_conn_mutex_unlock_later;
-    conn->mta_conn_mutex_unlock_later = TRUE;
 #if defined(HS_HAS_SQLCOM) && defined(HAVE_HANDLERSOCKET)
     if (conn->conn_kind == SPIDER_CONN_KIND_MYSQL)
     {
@@ -11910,7 +12182,15 @@ int spider_db_close_handler(
       dbton_hdl->reset_sql(SPIDER_SQL_TYPE_HANDLER);
       if ((error_num = dbton_hdl->append_close_handler_part(
         SPIDER_SQL_TYPE_HANDLER, link_idx)))
+      {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+        conn->mta_conn_mutex_lock_already = FALSE;
+        conn->mta_conn_mutex_unlock_later = FALSE;
+        SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+        pthread_mutex_unlock(&conn->mta_conn_mutex);
         DBUG_RETURN(error_num);
+      }
 
       spider_conn_set_timeout_from_share(conn, link_idx, spider->trx->thd,
         spider->share);
@@ -11936,24 +12216,22 @@ int spider_db_close_handler(
       goto error;
     conn->opened_handlers--;
     DBUG_PRINT("info",("spider opened_handlers=%u", conn->opened_handlers));
-    conn->mta_conn_mutex_lock_already = tmp_mta_conn_mutex_lock_already;
-    conn->mta_conn_mutex_unlock_later = tmp_mta_conn_mutex_unlock_later;
-    if (!tmp_mta_conn_mutex_unlock_later)
-    {
-      SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-      pthread_mutex_unlock(&conn->mta_conn_mutex);
-    }
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = FALSE;
+  conn->mta_conn_mutex_unlock_later = FALSE;
+  SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+  pthread_mutex_unlock(&conn->mta_conn_mutex);
   DBUG_RETURN(0);
 
 error:
-  conn->mta_conn_mutex_lock_already = tmp_mta_conn_mutex_lock_already;
-  conn->mta_conn_mutex_unlock_later = tmp_mta_conn_mutex_unlock_later;
-  if (!tmp_mta_conn_mutex_unlock_later)
-  {
-    SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-    pthread_mutex_unlock(&conn->mta_conn_mutex);
-  }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = FALSE;
+  conn->mta_conn_mutex_unlock_later = FALSE;
+  SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+  pthread_mutex_unlock(&conn->mta_conn_mutex);
   DBUG_RETURN(error_num);
 }
 
@@ -11990,3 +12268,4 @@ bool spider_db_conn_is_network_error(
   }
   DBUG_RETURN(FALSE);
 }
+
diff --git a/storage/spider/spd_db_mysql.cc b/storage/spider/spd_db_mysql.cc
index db610262c2b..420f14f9919 100644
--- a/storage/spider/spd_db_mysql.cc
+++ b/storage/spider/spd_db_mysql.cc
@@ -2292,10 +2292,6 @@ void spider_db_mbase::print_warnings(
     if (!(db_conn->server_status & SERVER_MORE_RESULTS_EXISTS))
 #endif
     {
-/*
-      pthread_mutex_lock(&conn->mta_conn_mutex);
-      SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
-*/
       if (
         spider_param_dry_access() ||
         !mysql_real_query(db_conn, SPIDER_SQL_SHOW_WARNINGS_STR,
@@ -2313,18 +2309,10 @@ void spider_db_mbase::print_warnings(
           {
             if (res)
               mysql_free_result(res);
-/*
-            SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-            pthread_mutex_unlock(&conn->mta_conn_mutex);
-*/
             DBUG_VOID_RETURN;
           }
           /* no record is ok */
         }
-/*
-        SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-        pthread_mutex_unlock(&conn->mta_conn_mutex);
-*/
         num_fields = mysql_num_fields(res);
         if (num_fields != 3)
         {
@@ -2343,11 +2331,6 @@ void spider_db_mbase::print_warnings(
         }
         if (res)
           mysql_free_result(res);
-      } else {
-/*
-        SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-        pthread_mutex_unlock(&conn->mta_conn_mutex);
-*/
       }
     }
   }
@@ -2562,14 +2545,31 @@ int spider_db_mbase::consistent_snapshot(
 ) {
   DBUG_ENTER("spider_db_mbase::consistent_snapshot");
   DBUG_PRINT("info",("spider this=%p", this));
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+  pthread_mutex_lock(&conn->mta_conn_mutex);
+  SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+  conn->need_mon = need_mon;
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = TRUE;
+  conn->mta_conn_mutex_unlock_later = TRUE;
   if (spider_db_query(
     conn,
     SPIDER_SQL_START_CONSISTENT_SNAPSHOT_STR,
     SPIDER_SQL_START_CONSISTENT_SNAPSHOT_LEN,
     -1,
     need_mon)
-  )
+  ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = FALSE;
+    conn->mta_conn_mutex_unlock_later = FALSE;
     DBUG_RETURN(spider_db_errorno(conn));
+  }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = FALSE;
+  conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
   pthread_mutex_unlock(&conn->mta_conn_mutex);
   DBUG_RETURN(0);
@@ -2587,16 +2587,18 @@ int spider_db_mbase::start_transaction(
 ) {
   DBUG_ENTER("spider_db_mbase::start_transaction");
   DBUG_PRINT("info",("spider this=%p", this));
+  pthread_mutex_assert_owner(&conn->mta_conn_mutex);
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
   if (spider_db_query(
     conn,
     SPIDER_SQL_START_TRANSACTION_STR,
     SPIDER_SQL_START_TRANSACTION_LEN,
     -1,
     need_mon)
-  )
+  ) {
     DBUG_RETURN(spider_db_errorno(conn));
-  SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-  pthread_mutex_unlock(&conn->mta_conn_mutex);
+  }
   DBUG_RETURN(0);
 }
 
@@ -2605,14 +2607,31 @@ int spider_db_mbase::commit(
 ) {
   DBUG_ENTER("spider_db_mbase::commit");
   DBUG_PRINT("info",("spider this=%p", this));
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+  pthread_mutex_lock(&conn->mta_conn_mutex);
+  SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+  conn->need_mon = need_mon;
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = TRUE;
+  conn->mta_conn_mutex_unlock_later = TRUE;
   if (spider_db_query(
     conn,
     SPIDER_SQL_COMMIT_STR,
     SPIDER_SQL_COMMIT_LEN,
     -1,
     need_mon)
-  )
+  ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = FALSE;
+    conn->mta_conn_mutex_unlock_later = FALSE;
     DBUG_RETURN(spider_db_errorno(conn));
+  }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = FALSE;
+  conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
   pthread_mutex_unlock(&conn->mta_conn_mutex);
   DBUG_RETURN(0);
@@ -2625,6 +2644,13 @@ int spider_db_mbase::rollback(
   int error_num;
   DBUG_ENTER("spider_db_mbase::rollback");
   DBUG_PRINT("info",("spider this=%p", this));
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+  pthread_mutex_lock(&conn->mta_conn_mutex);
+  SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+  conn->need_mon = need_mon;
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = TRUE;
   conn->mta_conn_mutex_unlock_later = TRUE;
   if (spider_db_query(
     conn,
@@ -2641,12 +2667,18 @@ int spider_db_mbase::rollback(
     )
       conn->thd->clear_error();
     else {
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
       pthread_mutex_unlock(&conn->mta_conn_mutex);
       DBUG_RETURN(error_num);
     }
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = FALSE;
   conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
   pthread_mutex_unlock(&conn->mta_conn_mutex);
@@ -2683,14 +2715,31 @@ int spider_db_mbase::xa_end(
   sql_str.length(0);
   sql_str.q_append(SPIDER_SQL_XA_END_STR, SPIDER_SQL_XA_END_LEN);
   spider_db_append_xid_str(&sql_str, xid);
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+  pthread_mutex_lock(&conn->mta_conn_mutex);
+  SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+  conn->need_mon = need_mon;
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = TRUE;
+  conn->mta_conn_mutex_unlock_later = TRUE;
   if (spider_db_query(
     conn,
     sql_str.ptr(),
     sql_str.length(),
     -1,
     need_mon)
-  )
+  ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = FALSE;
+    conn->mta_conn_mutex_unlock_later = FALSE;
     DBUG_RETURN(spider_db_errorno(conn));
+  }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = FALSE;
+  conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
   pthread_mutex_unlock(&conn->mta_conn_mutex);
   DBUG_RETURN(0);
@@ -2709,14 +2758,31 @@ int spider_db_mbase::xa_prepare(
   sql_str.length(0);
   sql_str.q_append(SPIDER_SQL_XA_PREPARE_STR, SPIDER_SQL_XA_PREPARE_LEN);
   spider_db_append_xid_str(&sql_str, xid);
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+  pthread_mutex_lock(&conn->mta_conn_mutex);
+  SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+  conn->need_mon = need_mon;
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = TRUE;
+  conn->mta_conn_mutex_unlock_later = TRUE;
   if (spider_db_query(
     conn,
     sql_str.ptr(),
     sql_str.length(),
     -1,
     need_mon)
-  )
+  ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = FALSE;
+    conn->mta_conn_mutex_unlock_later = FALSE;
     DBUG_RETURN(spider_db_errorno(conn));
+  }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = FALSE;
+  conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
   pthread_mutex_unlock(&conn->mta_conn_mutex);
   DBUG_RETURN(0);
@@ -2735,14 +2801,31 @@ int spider_db_mbase::xa_commit(
   sql_str.length(0);
   sql_str.q_append(SPIDER_SQL_XA_COMMIT_STR, SPIDER_SQL_XA_COMMIT_LEN);
   spider_db_append_xid_str(&sql_str, xid);
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+  pthread_mutex_lock(&conn->mta_conn_mutex);
+  SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+  conn->need_mon = need_mon;
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = TRUE;
+  conn->mta_conn_mutex_unlock_later = TRUE;
   if (spider_db_query(
     conn,
     sql_str.ptr(),
     sql_str.length(),
     -1,
     need_mon)
-  )
+  ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = FALSE;
+    conn->mta_conn_mutex_unlock_later = FALSE;
     DBUG_RETURN(spider_db_errorno(conn));
+  }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = FALSE;
+  conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
   pthread_mutex_unlock(&conn->mta_conn_mutex);
   DBUG_RETURN(0);
@@ -2761,14 +2844,31 @@ int spider_db_mbase::xa_rollback(
   sql_str.length(0);
   sql_str.q_append(SPIDER_SQL_XA_ROLLBACK_STR, SPIDER_SQL_XA_ROLLBACK_LEN);
   spider_db_append_xid_str(&sql_str, xid);
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+  pthread_mutex_lock(&conn->mta_conn_mutex);
+  SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+  conn->need_mon = need_mon;
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = TRUE;
+  conn->mta_conn_mutex_unlock_later = TRUE;
   if (spider_db_query(
     conn,
     sql_str.ptr(),
     sql_str.length(),
     -1,
     need_mon)
-  )
+  ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = FALSE;
+    conn->mta_conn_mutex_unlock_later = FALSE;
     DBUG_RETURN(spider_db_errorno(conn));
+  }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = FALSE;
+  conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
   pthread_mutex_unlock(&conn->mta_conn_mutex);
   DBUG_RETURN(0);
@@ -2790,50 +2890,118 @@ int spider_db_mbase::set_trx_isolation(
   switch (trx_isolation)
   {
     case ISO_READ_UNCOMMITTED:
+      pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+      pthread_mutex_lock(&conn->mta_conn_mutex);
+      SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+      conn->need_mon = need_mon;
+      DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = TRUE;
+      conn->mta_conn_mutex_unlock_later = TRUE;
       if (spider_db_query(
         conn,
         SPIDER_SQL_ISO_READ_UNCOMMITTED_STR,
         SPIDER_SQL_ISO_READ_UNCOMMITTED_LEN,
         -1,
         need_mon)
-      )
+      ) {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+        conn->mta_conn_mutex_lock_already = FALSE;
+        conn->mta_conn_mutex_unlock_later = FALSE;
         DBUG_RETURN(spider_db_errorno(conn));
+      }
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = FALSE;
+      conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
       pthread_mutex_unlock(&conn->mta_conn_mutex);
       break;
     case ISO_READ_COMMITTED:
+      pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+      pthread_mutex_lock(&conn->mta_conn_mutex);
+      SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+      conn->need_mon = need_mon;
+      DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = TRUE;
+      conn->mta_conn_mutex_unlock_later = TRUE;
       if (spider_db_query(
         conn,
         SPIDER_SQL_ISO_READ_COMMITTED_STR,
         SPIDER_SQL_ISO_READ_COMMITTED_LEN,
         -1,
         need_mon)
-      )
+      ) {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+        conn->mta_conn_mutex_lock_already = FALSE;
+        conn->mta_conn_mutex_unlock_later = FALSE;
         DBUG_RETURN(spider_db_errorno(conn));
+      }
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = FALSE;
+      conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
       pthread_mutex_unlock(&conn->mta_conn_mutex);
       break;
     case ISO_REPEATABLE_READ:
+      pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+      pthread_mutex_lock(&conn->mta_conn_mutex);
+      SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+      conn->need_mon = need_mon;
+      DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = TRUE;
+      conn->mta_conn_mutex_unlock_later = TRUE;
       if (spider_db_query(
         conn,
         SPIDER_SQL_ISO_REPEATABLE_READ_STR,
         SPIDER_SQL_ISO_REPEATABLE_READ_LEN,
         -1,
         need_mon)
-      )
+      ) {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+        conn->mta_conn_mutex_lock_already = FALSE;
+        conn->mta_conn_mutex_unlock_later = FALSE;
         DBUG_RETURN(spider_db_errorno(conn));
+      }
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = FALSE;
+      conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
       pthread_mutex_unlock(&conn->mta_conn_mutex);
       break;
     case ISO_SERIALIZABLE:
+      pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+      pthread_mutex_lock(&conn->mta_conn_mutex);
+      SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+      conn->need_mon = need_mon;
+      DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = TRUE;
+      conn->mta_conn_mutex_unlock_later = TRUE;
       if (spider_db_query(
         conn,
         SPIDER_SQL_ISO_SERIALIZABLE_STR,
         SPIDER_SQL_ISO_SERIALIZABLE_LEN,
         -1,
         need_mon)
-      )
+      ) {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+        conn->mta_conn_mutex_lock_already = FALSE;
+        conn->mta_conn_mutex_unlock_later = FALSE;
         DBUG_RETURN(spider_db_errorno(conn));
+      }
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = FALSE;
+      conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
       pthread_mutex_unlock(&conn->mta_conn_mutex);
       break;
@@ -2858,25 +3026,59 @@ int spider_db_mbase::set_autocommit(
   DBUG_PRINT("info",("spider this=%p", this));
   if (autocommit)
   {
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+    pthread_mutex_lock(&conn->mta_conn_mutex);
+    SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+    conn->need_mon = need_mon;
+    DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = TRUE;
+    conn->mta_conn_mutex_unlock_later = TRUE;
     if (spider_db_query(
       conn,
       SPIDER_SQL_AUTOCOMMIT_ON_STR,
       SPIDER_SQL_AUTOCOMMIT_ON_LEN,
       -1,
       need_mon)
-    )
+    ) {
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = FALSE;
+      conn->mta_conn_mutex_unlock_later = FALSE;
       DBUG_RETURN(spider_db_errorno(conn));
+    }
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = FALSE;
+    conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
     pthread_mutex_unlock(&conn->mta_conn_mutex);
   } else {
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+    pthread_mutex_lock(&conn->mta_conn_mutex);
+    SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+    conn->need_mon = need_mon;
+    DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = TRUE;
+    conn->mta_conn_mutex_unlock_later = TRUE;
     if (spider_db_query(
       conn,
       SPIDER_SQL_AUTOCOMMIT_OFF_STR,
       SPIDER_SQL_AUTOCOMMIT_OFF_LEN,
       -1,
       need_mon)
-    )
+    ) {
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = FALSE;
+      conn->mta_conn_mutex_unlock_later = FALSE;
       DBUG_RETURN(spider_db_errorno(conn));
+    }
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = FALSE;
+    conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
     pthread_mutex_unlock(&conn->mta_conn_mutex);
   }
@@ -2898,25 +3100,59 @@ int spider_db_mbase::set_sql_log_off(
   DBUG_PRINT("info",("spider this=%p", this));
   if (sql_log_off)
   {
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+    pthread_mutex_lock(&conn->mta_conn_mutex);
+    SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+    conn->need_mon = need_mon;
+    DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = TRUE;
+    conn->mta_conn_mutex_unlock_later = TRUE;
     if (spider_db_query(
       conn,
       SPIDER_SQL_SQL_LOG_ON_STR,
       SPIDER_SQL_SQL_LOG_ON_LEN,
       -1,
       need_mon)
-    )
+    ) {
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = FALSE;
+      conn->mta_conn_mutex_unlock_later = FALSE;
       DBUG_RETURN(spider_db_errorno(conn));
+    }
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = FALSE;
+    conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
     pthread_mutex_unlock(&conn->mta_conn_mutex);
   } else {
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+    pthread_mutex_lock(&conn->mta_conn_mutex);
+    SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+    conn->need_mon = need_mon;
+    DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = TRUE;
+    conn->mta_conn_mutex_unlock_later = TRUE;
     if (spider_db_query(
       conn,
       SPIDER_SQL_SQL_LOG_OFF_STR,
       SPIDER_SQL_SQL_LOG_OFF_LEN,
       -1,
       need_mon)
-    )
+    ) {
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = FALSE;
+      conn->mta_conn_mutex_unlock_later = FALSE;
       DBUG_RETURN(spider_db_errorno(conn));
+    }
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = FALSE;
+    conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
     pthread_mutex_unlock(&conn->mta_conn_mutex);
   }
@@ -2948,14 +3184,31 @@ int spider_db_mbase::set_wait_timeout(
     DBUG_RETURN(HA_ERR_OUT_OF_MEM);
   sql_str.q_append(SPIDER_SQL_WAIT_TIMEOUT_STR, SPIDER_SQL_WAIT_TIMEOUT_LEN);
   sql_str.q_append(timeout_str, timeout_str_length);
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+  pthread_mutex_lock(&conn->mta_conn_mutex);
+  SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+  conn->need_mon = need_mon;
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = TRUE;
+  conn->mta_conn_mutex_unlock_later = TRUE;
   if (spider_db_query(
     conn,
     sql_str.ptr(),
     sql_str.length(),
     -1,
     need_mon)
-  )
+  ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = FALSE;
+    conn->mta_conn_mutex_unlock_later = FALSE;
     DBUG_RETURN(spider_db_errorno(conn));
+  }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = FALSE;
+  conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
   pthread_mutex_unlock(&conn->mta_conn_mutex);
   DBUG_RETURN(0);
@@ -2996,14 +3249,31 @@ int spider_db_mbase::set_sql_mode(
     }
   }
   sql_str.q_append(SPIDER_SQL_VALUE_QUOTE_STR, SPIDER_SQL_VALUE_QUOTE_LEN);
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+  pthread_mutex_lock(&conn->mta_conn_mutex);
+  SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+  conn->need_mon = need_mon;
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = TRUE;
+  conn->mta_conn_mutex_unlock_later = TRUE;
   if (spider_db_query(
     conn,
     sql_str.ptr(),
     sql_str.length(),
     -1,
     need_mon)
-  )
+  ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = FALSE;
+    conn->mta_conn_mutex_unlock_later = FALSE;
     DBUG_RETURN(spider_db_errorno(conn));
+  }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = FALSE;
+  conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
   pthread_mutex_unlock(&conn->mta_conn_mutex);
   DBUG_RETURN(0);
@@ -3033,14 +3303,31 @@ int spider_db_mbase::set_time_zone(
   sql_str.q_append(SPIDER_SQL_TIME_ZONE_STR, SPIDER_SQL_TIME_ZONE_LEN);
   sql_str.q_append(tz_str->ptr(), tz_str->length());
   sql_str.q_append(SPIDER_SQL_VALUE_QUOTE_STR, SPIDER_SQL_VALUE_QUOTE_LEN);
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+  pthread_mutex_lock(&conn->mta_conn_mutex);
+  SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+  conn->need_mon = need_mon;
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = TRUE;
+  conn->mta_conn_mutex_unlock_later = TRUE;
   if (spider_db_query(
     conn,
     sql_str.ptr(),
     sql_str.length(),
     -1,
     need_mon)
-  )
+  ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = FALSE;
+    conn->mta_conn_mutex_unlock_later = FALSE;
     DBUG_RETURN(spider_db_errorno(conn));
+  }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = FALSE;
+  conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
   pthread_mutex_unlock(&conn->mta_conn_mutex);
   DBUG_RETURN(0);
@@ -3057,9 +3344,12 @@ int spider_db_mbase::exec_simple_sql_with_result(
 ) {
   int error_num;
   DBUG_ENTER("spider_db_mbase::exec_simple_sql_with_result");
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
   pthread_mutex_lock(&conn->mta_conn_mutex);
   SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
   conn->need_mon = need_mon;
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = TRUE;
   conn->mta_conn_mutex_unlock_later = TRUE;
   spider_conn_set_timeout_from_share(conn, all_link_idx, trx->thd,
@@ -3085,6 +3375,8 @@ int spider_db_mbase::exec_simple_sql_with_result(
       if ((error_num = spider_db_ping_internal(share, conn,
         all_link_idx, need_mon)))
       {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -3095,6 +3387,8 @@ int spider_db_mbase::exec_simple_sql_with_result(
       if ((error_num = spider_db_set_names_internal(trx, share, conn,
         all_link_idx, need_mon)))
       {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -3111,12 +3405,16 @@ int spider_db_mbase::exec_simple_sql_with_result(
         -1,
         need_mon)
       ) {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         DBUG_PRINT("info", ("spider error_num=%d 3", error_num));
         DBUG_RETURN(spider_db_errorno(conn));
       }
     } else {
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -3127,18 +3425,29 @@ int spider_db_mbase::exec_simple_sql_with_result(
   }
   if (!(*res = store_result(NULL, NULL, &error_num)))
   {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
-    if (error_num || (error_num = spider_db_errorno(conn)))
+    if (error_num)
     {
+      SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+      pthread_mutex_unlock(&conn->mta_conn_mutex);
       DBUG_PRINT("info", ("spider error_num=%d 5", error_num));
       DBUG_RETURN(error_num);
+    }
+    else if ((error_num = spider_db_errorno(conn)))
+    {
+      DBUG_PRINT("info", ("spider error_num=%d 6", error_num));
+      DBUG_RETURN(error_num);
     } else {
-      DBUG_PRINT("info", ("spider error_num=%d 6",
+      DBUG_PRINT("info", ("spider error_num=%d 7",
         ER_QUERY_ON_FOREIGN_DATA_SOURCE));
       DBUG_RETURN(ER_QUERY_ON_FOREIGN_DATA_SOURCE);
     }
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = FALSE;
   conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -7968,6 +8277,14 @@ int spider_mbase_share::discover_table_structure(
     ) {
       DBUG_RETURN(error_num);
     }
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+    pthread_mutex_lock(&conn->mta_conn_mutex);
+    SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+    conn->need_mon = &need_mon;
+    DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = TRUE;
+    conn->mta_conn_mutex_unlock_later = TRUE;
     if (!conn->disable_reconnect)
     {
       ha_spider tmp_spider;
@@ -7980,14 +8297,15 @@ int spider_mbase_share::discover_table_structure(
       if ((error_num = spider_db_ping(&tmp_spider, conn, 0)))
       {
         DBUG_PRINT("info",("spider spider_db_ping error"));
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+        conn->mta_conn_mutex_lock_already = FALSE;
+        conn->mta_conn_mutex_unlock_later = FALSE;
+        SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+        pthread_mutex_unlock(&conn->mta_conn_mutex);
         continue;
       }
     }
-    pthread_mutex_lock(&conn->mta_conn_mutex);
-    SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
-    conn->need_mon = &need_mon;
-    conn->mta_conn_mutex_lock_already = TRUE;
-    conn->mta_conn_mutex_unlock_later = TRUE;
     spider_conn_set_timeout_from_share(conn, roop_count, trx->thd,
       spider_share);
     if (
@@ -8004,6 +8322,8 @@ int spider_mbase_share::discover_table_structure(
       )
     ) {
       DBUG_PRINT("info",("spider spider_get_trx error"));
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -8023,6 +8343,8 @@ int spider_mbase_share::discover_table_structure(
       if (error_num || (error_num = spider_db_errorno(conn)))
       {
         DBUG_PRINT("info",("spider column store error"));
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -8031,6 +8353,8 @@ int spider_mbase_share::discover_table_structure(
       }
       /* no record */
       DBUG_PRINT("info",("spider column no record error"));
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -8043,6 +8367,8 @@ int spider_mbase_share::discover_table_structure(
       DBUG_PRINT("info",("spider column fetch error"));
       res->free_result();
       delete res;
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -8059,6 +8385,8 @@ int spider_mbase_share::discover_table_structure(
     if (conn->db_conn->next_result())
     {
       DBUG_PRINT("info",("spider single result error"));
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -8071,6 +8399,8 @@ int spider_mbase_share::discover_table_structure(
       if (error_num || (error_num = spider_db_errorno(conn)))
       {
         DBUG_PRINT("info",("spider index store error"));
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -8079,6 +8409,8 @@ int spider_mbase_share::discover_table_structure(
       }
       /* no record */
       DBUG_PRINT("info",("spider index no record error"));
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -8091,6 +8423,8 @@ int spider_mbase_share::discover_table_structure(
       DBUG_PRINT("info",("spider index fetch error"));
       res->free_result();
       delete res;
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -8102,6 +8436,8 @@ int spider_mbase_share::discover_table_structure(
     if (conn->db_conn->next_result())
     {
       DBUG_PRINT("info",("spider dual result error"));
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -8114,6 +8450,8 @@ int spider_mbase_share::discover_table_structure(
       if (error_num || (error_num = spider_db_errorno(conn)))
       {
         DBUG_PRINT("info",("spider table store error"));
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -8122,6 +8460,8 @@ int spider_mbase_share::discover_table_structure(
       }
       /* no record */
       DBUG_PRINT("info",("spider table no record error"));
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -8134,6 +8474,8 @@ int spider_mbase_share::discover_table_structure(
       DBUG_PRINT("info",("spider table fetch error"));
       res->free_result();
       delete res;
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -8142,6 +8484,8 @@ int spider_mbase_share::discover_table_structure(
     }
     res->free_result();
     delete res;
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -13580,9 +13924,12 @@ int spider_mbase_handler::show_table_status(
 
   if (sts_mode == 1)
   {
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
     pthread_mutex_lock(&conn->mta_conn_mutex);
     SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
     conn->need_mon = &spider->need_mons[link_idx];
+    DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = TRUE;
     conn->mta_conn_mutex_unlock_later = TRUE;
     conn->disable_connect_retry = TRUE;
@@ -13608,6 +13955,8 @@ int spider_mbase_handler::show_table_status(
         if ((error_num = spider_db_ping(spider, conn, link_idx)))
         {
           conn->disable_connect_retry = FALSE;
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -13617,6 +13966,8 @@ int spider_mbase_handler::show_table_status(
         if ((error_num = spider_db_set_names(spider, conn, link_idx)))
         {
           conn->disable_connect_retry = FALSE;
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -13633,12 +13984,16 @@ int spider_mbase_handler::show_table_status(
           &spider->need_mons[link_idx])
         ) {
           conn->disable_connect_retry = FALSE;
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           DBUG_RETURN(spider_db_errorno(conn));
         }
       } else {
         conn->disable_connect_retry = FALSE;
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -13655,6 +14010,8 @@ int spider_mbase_handler::show_table_status(
     if (spider_param_dry_access())
     {
       conn->disable_connect_retry = FALSE;
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -13664,9 +14021,17 @@ int spider_mbase_handler::show_table_status(
     if (!(res = conn->db_conn->store_result(NULL, &request_key, &error_num)))
     {
       conn->disable_connect_retry = FALSE;
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
-      if (error_num || (error_num = spider_db_errorno(conn)))
+      if (error_num)
+      {
+        SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+        pthread_mutex_unlock(&conn->mta_conn_mutex);
+        DBUG_RETURN(error_num);
+      }
+      else if ((error_num = spider_db_errorno(conn)))
         DBUG_RETURN(error_num);
       else {
         my_printf_error(ER_SPIDER_REMOTE_TABLE_NOT_FOUND_NUM,
@@ -13678,6 +14043,8 @@ int spider_mbase_handler::show_table_status(
       }
     }
     conn->disable_connect_retry = FALSE;
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -13713,9 +14080,12 @@ int spider_mbase_handler::show_table_status(
       DBUG_RETURN(error_num);
     }
   } else {
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
     pthread_mutex_lock(&conn->mta_conn_mutex);
     SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
     conn->need_mon = &spider->need_mons[link_idx];
+    DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = TRUE;
     conn->mta_conn_mutex_unlock_later = TRUE;
     conn->disable_connect_retry = TRUE;
@@ -13741,6 +14111,8 @@ int spider_mbase_handler::show_table_status(
         if ((error_num = spider_db_ping(spider, conn, link_idx)))
         {
           conn->disable_connect_retry = FALSE;
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -13750,6 +14122,8 @@ int spider_mbase_handler::show_table_status(
         if ((error_num = spider_db_set_names(spider, conn, link_idx)))
         {
           conn->disable_connect_retry = FALSE;
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -13766,12 +14140,16 @@ int spider_mbase_handler::show_table_status(
           &spider->need_mons[link_idx])
         ) {
           conn->disable_connect_retry = FALSE;
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           DBUG_RETURN(spider_db_errorno(conn));
         }
       } else {
         conn->disable_connect_retry = FALSE;
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -13788,6 +14166,8 @@ int spider_mbase_handler::show_table_status(
     if (spider_param_dry_access())
     {
       conn->disable_connect_retry = FALSE;
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -13797,6 +14177,8 @@ int spider_mbase_handler::show_table_status(
     if (!(res = conn->db_conn->store_result(NULL, &request_key, &error_num)))
     {
       conn->disable_connect_retry = FALSE;
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       if (error_num || (error_num = spider_db_errorno(conn)))
@@ -13805,6 +14187,8 @@ int spider_mbase_handler::show_table_status(
         DBUG_RETURN(ER_QUERY_ON_FOREIGN_DATA_SOURCE);
     }
     conn->disable_connect_retry = FALSE;
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -13881,9 +14265,12 @@ int spider_mbase_handler::show_index(
   DBUG_PRINT("info",("spider crd_mode=%d", crd_mode));
   if (crd_mode == 1)
   {
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
     pthread_mutex_lock(&conn->mta_conn_mutex);
     SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
     conn->need_mon = &spider->need_mons[link_idx];
+    DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = TRUE;
     conn->mta_conn_mutex_unlock_later = TRUE;
     spider_conn_set_timeout_from_share(conn, link_idx, spider->trx->thd,
@@ -13907,6 +14294,8 @@ int spider_mbase_handler::show_index(
         /* retry */
         if ((error_num = spider_db_ping(spider, conn, link_idx)))
         {
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -13915,6 +14304,8 @@ int spider_mbase_handler::show_index(
         }
         if ((error_num = spider_db_set_names(spider, conn, link_idx)))
         {
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -13930,11 +14321,15 @@ int spider_mbase_handler::show_index(
           -1,
           &spider->need_mons[link_idx])
         ) {
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           DBUG_RETURN(spider_db_errorno(conn));
         }
       } else {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -13952,6 +14347,8 @@ int spider_mbase_handler::show_index(
     {
       if (error_num || (error_num = spider_db_errorno(conn)))
       {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -13960,6 +14357,8 @@ int spider_mbase_handler::show_index(
       }
       /* no record is ok */
     }
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14014,9 +14413,12 @@ int spider_mbase_handler::show_index(
       DBUG_RETURN(error_num);
     }
   } else {
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
     pthread_mutex_lock(&conn->mta_conn_mutex);
     SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
     conn->need_mon = &spider->need_mons[link_idx];
+    DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = TRUE;
     conn->mta_conn_mutex_unlock_later = TRUE;
     spider_conn_set_timeout_from_share(conn, link_idx, spider->trx->thd,
@@ -14040,6 +14442,8 @@ int spider_mbase_handler::show_index(
         /* retry */
         if ((error_num = spider_db_ping(spider, conn, link_idx)))
         {
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14048,6 +14452,8 @@ int spider_mbase_handler::show_index(
         }
         if ((error_num = spider_db_set_names(spider, conn, link_idx)))
         {
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14063,11 +14469,15 @@ int spider_mbase_handler::show_index(
           -1,
           &spider->need_mons[link_idx])
         ) {
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           DBUG_RETURN(spider_db_errorno(conn));
         }
       } else {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14085,6 +14495,8 @@ int spider_mbase_handler::show_index(
     {
       if (error_num || (error_num = spider_db_errorno(conn)))
       {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14093,6 +14505,8 @@ int spider_mbase_handler::show_index(
       }
       /* no record is ok */
     }
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14202,9 +14616,12 @@ int spider_mbase_handler::simple_action(
       DBUG_ASSERT(0);
       DBUG_RETURN(0);
   }
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
   pthread_mutex_lock(&conn->mta_conn_mutex);
   SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
   conn->need_mon = &spider->need_mons[link_idx];
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = TRUE;
   conn->mta_conn_mutex_unlock_later = TRUE;
   spider_conn_set_timeout_from_share(conn, link_idx, spider->trx->thd,
@@ -14228,6 +14645,8 @@ int spider_mbase_handler::simple_action(
       /* retry */
       if ((error_num = spider_db_ping(spider, conn, link_idx)))
       {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14237,6 +14656,8 @@ int spider_mbase_handler::simple_action(
       }
       if ((error_num = spider_db_set_names(spider, conn, link_idx)))
       {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14253,12 +14674,16 @@ int spider_mbase_handler::simple_action(
         -1,
         &spider->need_mons[link_idx])
       ) {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         DBUG_PRINT("info", ("spider error_num=%d 3", error_num));
         DBUG_RETURN(spider_db_errorno(conn));
       }
     } else {
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14275,18 +14700,29 @@ int spider_mbase_handler::simple_action(
   request_key.next = NULL;
   if (!(res = conn->db_conn->store_result(NULL, &request_key, &error_num)))
   {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
-    if (error_num || (error_num = spider_db_errorno(conn)))
+    if (error_num)
     {
+      SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+      pthread_mutex_unlock(&conn->mta_conn_mutex);
       DBUG_PRINT("info", ("spider error_num=%d 5", error_num));
       DBUG_RETURN(error_num);
+    }
+    else if ((error_num = spider_db_errorno(conn)))
+    {
+      DBUG_PRINT("info", ("spider error_num=%d 6", error_num));
+      DBUG_RETURN(error_num);
     } else {
-      DBUG_PRINT("info", ("spider error_num=%d 6",
+      DBUG_PRINT("info", ("spider error_num=%d 7",
         ER_QUERY_ON_FOREIGN_DATA_SOURCE));
       DBUG_RETURN(ER_QUERY_ON_FOREIGN_DATA_SOURCE);
     }
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = FALSE;
   conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14372,9 +14808,12 @@ ha_rows spider_mbase_handler::explain_select(
     DBUG_RETURN(HA_POS_ERROR);
   }
 
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
   pthread_mutex_lock(&conn->mta_conn_mutex);
   SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
   conn->need_mon = &spider->need_mons[link_idx];
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = TRUE;
   conn->mta_conn_mutex_unlock_later = TRUE;
   spider_conn_set_timeout_from_share(conn, link_idx, spider->trx->thd,
@@ -14400,6 +14839,8 @@ ha_rows spider_mbase_handler::explain_select(
       {
         if (spider->check_error_mode(error_num))
           my_errno = error_num;
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14410,6 +14851,8 @@ ha_rows spider_mbase_handler::explain_select(
       {
         if (spider->check_error_mode(error_num))
           my_errno = error_num;
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14428,6 +14871,8 @@ ha_rows spider_mbase_handler::explain_select(
         error_num = spider_db_errorno(conn);
         if (spider->check_error_mode(error_num))
           my_errno = error_num;
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14437,6 +14882,8 @@ ha_rows spider_mbase_handler::explain_select(
     } else {
       if (spider->check_error_mode(error_num))
         my_errno = error_num;
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14456,6 +14903,8 @@ ha_rows spider_mbase_handler::explain_select(
     {
       if (spider->check_error_mode(error_num))
         my_errno = error_num;
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14463,6 +14912,8 @@ ha_rows spider_mbase_handler::explain_select(
       DBUG_RETURN(HA_POS_ERROR);
     } else {
       my_errno = ER_QUERY_ON_FOREIGN_DATA_SOURCE;
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14470,6 +14921,8 @@ ha_rows spider_mbase_handler::explain_select(
       DBUG_RETURN(HA_POS_ERROR);
     }
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = FALSE;
   conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14502,13 +14955,18 @@ int spider_mbase_handler::lock_tables(
   }
   if (str->length())
   {
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
     pthread_mutex_lock(&conn->mta_conn_mutex);
     SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
     conn->need_mon = &spider->need_mons[link_idx];
+    DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = TRUE;
     conn->mta_conn_mutex_unlock_later = TRUE;
     if ((error_num = spider_db_set_names(spider, conn, link_idx)))
     {
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14524,10 +14982,14 @@ int spider_mbase_handler::lock_tables(
       -1,
       &spider->need_mons[link_idx])
     ) {
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       DBUG_RETURN(spider_db_errorno(conn));
     }
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14562,14 +15024,31 @@ int spider_mbase_handler::unlock_tables(
     {
       spider_conn_set_timeout_from_share(conn, link_idx, spider->trx->thd,
         spider->share);
+      pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+      pthread_mutex_lock(&conn->mta_conn_mutex);
+      SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+      conn->need_mon = &spider->need_mons[link_idx];
+      DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = TRUE;
+      conn->mta_conn_mutex_unlock_later = TRUE;
       if (spider_db_query(
         conn,
         str->ptr(),
         str->length(),
         -1,
         &spider->need_mons[link_idx])
-      )
+      ) {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+        conn->mta_conn_mutex_lock_already = FALSE;
+        conn->mta_conn_mutex_unlock_later = FALSE;
         DBUG_RETURN(spider_db_errorno(conn));
+      }
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = FALSE;
+      conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
       pthread_mutex_unlock(&conn->mta_conn_mutex);
     }
@@ -14592,13 +15071,18 @@ int spider_mbase_handler::disable_keys(
   {
     DBUG_RETURN(error_num);
   }
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
   pthread_mutex_lock(&conn->mta_conn_mutex);
   SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
   conn->need_mon = &spider->need_mons[link_idx];
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = TRUE;
   conn->mta_conn_mutex_unlock_later = TRUE;
   if ((error_num = spider_db_set_names(spider, conn, link_idx)))
   {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14614,11 +15098,15 @@ int spider_mbase_handler::disable_keys(
     -1,
     &spider->need_mons[link_idx])
   ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     error_num = spider_db_errorno(conn);
     DBUG_RETURN(error_num);
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = FALSE;
   conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14641,13 +15129,18 @@ int spider_mbase_handler::enable_keys(
   {
     DBUG_RETURN(error_num);
   }
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
   pthread_mutex_lock(&conn->mta_conn_mutex);
   SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
   conn->need_mon = &spider->need_mons[link_idx];
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = TRUE;
   conn->mta_conn_mutex_unlock_later = TRUE;
   if ((error_num = spider_db_set_names(spider, conn, link_idx)))
   {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14663,11 +15156,15 @@ int spider_mbase_handler::enable_keys(
     -1,
     &spider->need_mons[link_idx])
   ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     error_num = spider_db_errorno(conn);
     DBUG_RETURN(error_num);
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = FALSE;
   conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14691,13 +15188,18 @@ int spider_mbase_handler::check_table(
   {
     DBUG_RETURN(error_num);
   }
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
   pthread_mutex_lock(&conn->mta_conn_mutex);
   SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
   conn->need_mon = &spider->need_mons[link_idx];
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = TRUE;
   conn->mta_conn_mutex_unlock_later = TRUE;
   if ((error_num = spider_db_set_names(spider, conn, link_idx)))
   {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14713,11 +15215,15 @@ int spider_mbase_handler::check_table(
     -1,
     &spider->need_mons[link_idx])
   ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     error_num = spider_db_errorno(conn);
     DBUG_RETURN(error_num);
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = FALSE;
   conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14741,13 +15247,18 @@ int spider_mbase_handler::repair_table(
   {
     DBUG_RETURN(error_num);
   }
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
   pthread_mutex_lock(&conn->mta_conn_mutex);
   SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
   conn->need_mon = &spider->need_mons[link_idx];
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = TRUE;
   conn->mta_conn_mutex_unlock_later = TRUE;
   if ((error_num = spider_db_set_names(spider, conn, link_idx)))
   {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14763,11 +15274,15 @@ int spider_mbase_handler::repair_table(
     -1,
     &spider->need_mons[link_idx])
   ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     error_num = spider_db_errorno(conn);
     DBUG_RETURN(error_num);
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = FALSE;
   conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14790,13 +15305,18 @@ int spider_mbase_handler::analyze_table(
   {
     DBUG_RETURN(error_num);
   }
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
   pthread_mutex_lock(&conn->mta_conn_mutex);
   SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
   conn->need_mon = &spider->need_mons[link_idx];
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = TRUE;
   conn->mta_conn_mutex_unlock_later = TRUE;
   if ((error_num = spider_db_set_names(spider, conn, link_idx)))
   {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14812,11 +15332,15 @@ int spider_mbase_handler::analyze_table(
     -1,
     &spider->need_mons[link_idx])
   ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     error_num = spider_db_errorno(conn);
     DBUG_RETURN(error_num);
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = FALSE;
   conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14839,13 +15363,18 @@ int spider_mbase_handler::optimize_table(
   {
     DBUG_RETURN(error_num);
   }
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
   pthread_mutex_lock(&conn->mta_conn_mutex);
   SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
   conn->need_mon = &spider->need_mons[link_idx];
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = TRUE;
   conn->mta_conn_mutex_unlock_later = TRUE;
   if ((error_num = spider_db_set_names(spider, conn, link_idx)))
   {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14861,11 +15390,15 @@ int spider_mbase_handler::optimize_table(
     -1,
     &spider->need_mons[link_idx])
   ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     error_num = spider_db_errorno(conn);
     DBUG_RETURN(error_num);
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = FALSE;
   conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -14891,6 +15424,14 @@ int spider_mbase_handler::flush_tables(
   }
   spider_conn_set_timeout_from_share(conn, link_idx, spider->trx->thd,
     share);
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+  pthread_mutex_lock(&conn->mta_conn_mutex);
+  SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+  conn->need_mon = &spider->need_mons[link_idx];
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = TRUE;
+  conn->mta_conn_mutex_unlock_later = TRUE;
   if (spider_db_query(
     conn,
     str->ptr(),
@@ -14898,9 +15439,17 @@ int spider_mbase_handler::flush_tables(
     -1,
     &spider->need_mons[link_idx])
   ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = FALSE;
+    conn->mta_conn_mutex_unlock_later = FALSE;
     error_num = spider_db_errorno(conn);
     DBUG_RETURN(error_num);
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = FALSE;
+  conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
   pthread_mutex_unlock(&conn->mta_conn_mutex);
   DBUG_RETURN(0);
@@ -14916,6 +15465,14 @@ int spider_mbase_handler::flush_logs(
   DBUG_PRINT("info",("spider this=%p", this));
   spider_conn_set_timeout_from_share(conn, link_idx, spider->trx->thd,
     share);
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+  pthread_mutex_lock(&conn->mta_conn_mutex);
+  SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+  conn->need_mon = &spider->need_mons[link_idx];
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = TRUE;
+  conn->mta_conn_mutex_unlock_later = TRUE;
   if (spider_db_query(
     conn,
     SPIDER_SQL_FLUSH_LOGS_STR,
@@ -14923,9 +15480,17 @@ int spider_mbase_handler::flush_logs(
     -1,
     &spider->need_mons[link_idx])
   ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = FALSE;
+    conn->mta_conn_mutex_unlock_later = FALSE;
     error_num = spider_db_errorno(conn);
     DBUG_RETURN(error_num);
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = FALSE;
+  conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
   pthread_mutex_unlock(&conn->mta_conn_mutex);
   DBUG_RETURN(0);
diff --git a/storage/spider/spd_db_oracle.cc b/storage/spider/spd_db_oracle.cc
index 6df105e9898..b7561ccb96e 100644
--- a/storage/spider/spd_db_oracle.cc
+++ b/storage/spider/spd_db_oracle.cc
@@ -1812,16 +1812,18 @@ int spider_db_oracle::start_transaction(
     }
     DBUG_RETURN(set_trx_isolation(conn->trx_isolation, need_mon));
   }
+  pthread_mutex_assert_owner(&conn->mta_conn_mutex);
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
   if (spider_db_query(
     conn,
     SPIDER_SQL_START_TRANSACTION_STR,
     SPIDER_SQL_START_TRANSACTION_LEN,
     -1,
     need_mon)
-  )
+  ) {
     DBUG_RETURN(spider_db_errorno(conn));
-  SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-  pthread_mutex_unlock(&conn->mta_conn_mutex);
+  }
   DBUG_RETURN(0);
 }
 
@@ -2010,14 +2012,31 @@ int spider_db_oracle::set_trx_isolation(
         DBUG_RETURN(exec_query(SPIDER_SQL_ISO_READ_COMMITTED_STR,
           SPIDER_SQL_ISO_READ_COMMITTED_LEN, -1));
       }
+      pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+      pthread_mutex_lock(&conn->mta_conn_mutex);
+      SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+      conn->need_mon = need_mon;
+      DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = TRUE;
+      conn->mta_conn_mutex_unlock_later = TRUE;
       if (spider_db_query(
         conn,
         SPIDER_SQL_ISO_READ_COMMITTED_STR,
         SPIDER_SQL_ISO_READ_COMMITTED_LEN,
         -1,
         need_mon)
-      )
+      ) {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+        conn->mta_conn_mutex_lock_already = FALSE;
+        conn->mta_conn_mutex_unlock_later = FALSE;
         DBUG_RETURN(spider_db_errorno(conn));
+      }
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = FALSE;
+      conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
       pthread_mutex_unlock(&conn->mta_conn_mutex);
       break;
@@ -2028,14 +2047,31 @@ int spider_db_oracle::set_trx_isolation(
         DBUG_RETURN(exec_query(SPIDER_SQL_ISO_SERIALIZABLE_STR,
           SPIDER_SQL_ISO_SERIALIZABLE_LEN, -1));
       }
+      pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+      pthread_mutex_lock(&conn->mta_conn_mutex);
+      SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+      conn->need_mon = need_mon;
+      DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = TRUE;
+      conn->mta_conn_mutex_unlock_later = TRUE;
       if (spider_db_query(
         conn,
         SPIDER_SQL_ISO_SERIALIZABLE_STR,
         SPIDER_SQL_ISO_SERIALIZABLE_LEN,
         -1,
         need_mon)
-      )
+      ) {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+        conn->mta_conn_mutex_lock_already = FALSE;
+        conn->mta_conn_mutex_unlock_later = FALSE;
         DBUG_RETURN(spider_db_errorno(conn));
+      }
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = FALSE;
+      conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
       pthread_mutex_unlock(&conn->mta_conn_mutex);
       break;
@@ -2065,14 +2101,31 @@ int spider_db_oracle::set_autocommit(
       DBUG_RETURN(exec_query(SPIDER_SQL_AUTOCOMMIT_ON_STR,
         SPIDER_SQL_AUTOCOMMIT_ON_LEN, -1));
     }
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+    pthread_mutex_lock(&conn->mta_conn_mutex);
+    SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+    conn->need_mon = need_mon;
+    DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = TRUE;
+    conn->mta_conn_mutex_unlock_later = TRUE;
     if (spider_db_query(
       conn,
       SPIDER_SQL_AUTOCOMMIT_ON_STR,
       SPIDER_SQL_AUTOCOMMIT_ON_LEN,
       -1,
       need_mon)
-    )
+    ) {
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = FALSE;
+      conn->mta_conn_mutex_unlock_later = FALSE;
       DBUG_RETURN(spider_db_errorno(conn));
+    }
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = FALSE;
+    conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
     pthread_mutex_unlock(&conn->mta_conn_mutex);
   } else {
@@ -2081,14 +2134,31 @@ int spider_db_oracle::set_autocommit(
       DBUG_RETURN(exec_query(SPIDER_SQL_AUTOCOMMIT_OFF_STR,
         SPIDER_SQL_AUTOCOMMIT_OFF_LEN, -1));
     }
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+    pthread_mutex_lock(&conn->mta_conn_mutex);
+    SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+    conn->need_mon = need_mon;
+    DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = TRUE;
+    conn->mta_conn_mutex_unlock_later = TRUE;
     if (spider_db_query(
       conn,
       SPIDER_SQL_AUTOCOMMIT_OFF_STR,
       SPIDER_SQL_AUTOCOMMIT_OFF_LEN,
       -1,
       need_mon)
-    )
+    ) {
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+      conn->mta_conn_mutex_lock_already = FALSE;
+      conn->mta_conn_mutex_unlock_later = FALSE;
       DBUG_RETURN(spider_db_errorno(conn));
+    }
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = FALSE;
+    conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
     pthread_mutex_unlock(&conn->mta_conn_mutex);
   }
@@ -11123,112 +11193,6 @@ int spider_oracle_handler::show_table_status(
 
   if (sts_mode == 1)
   {
-/*
-    pthread_mutex_lock(&conn->mta_conn_mutex);
-    SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
-    conn->need_mon = &spider->need_mons[link_idx];
-    conn->mta_conn_mutex_lock_already = TRUE;
-    conn->mta_conn_mutex_unlock_later = TRUE;
-    spider_conn_set_timeout_from_share(conn, link_idx, spider->trx->thd,
-      share);
-    if (
-      (error_num = spider_db_set_names(spider, conn, link_idx)) ||
-      (
-        spider_db_query(
-          conn,
-          oracle_share->show_table_status[0 + pos].ptr(),
-          oracle_share->show_table_status[0 + pos].length(),
-          -1,
-          &spider->need_mons[link_idx]) &&
-        (error_num = spider_db_errorno(conn))
-      )
-    ) {
-      if (
-        error_num == ER_SPIDER_REMOTE_SERVER_GONE_AWAY_NUM &&
-        !conn->disable_reconnect
-      ) {
-*/
-        /* retry */
-/*
-        if ((error_num = spider_db_ping(spider, conn, link_idx)))
-        {
-          conn->mta_conn_mutex_lock_already = FALSE;
-          conn->mta_conn_mutex_unlock_later = FALSE;
-          SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-          pthread_mutex_unlock(&conn->mta_conn_mutex);
-          DBUG_RETURN(error_num);
-        }
-        if ((error_num = spider_db_set_names(spider, conn, link_idx)))
-        {
-          conn->mta_conn_mutex_lock_already = FALSE;
-          conn->mta_conn_mutex_unlock_later = FALSE;
-          SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-          pthread_mutex_unlock(&conn->mta_conn_mutex);
-          DBUG_RETURN(error_num);
-        }
-        spider_conn_set_timeout_from_share(conn, link_idx, spider->trx->thd,
-          share);
-        if (spider_db_query(
-          conn,
-          oracle_share->show_table_status[0 + pos].ptr(),
-          oracle_share->show_table_status[0 + pos].length(),
-          -1,
-          &spider->need_mons[link_idx])
-        ) {
-          conn->mta_conn_mutex_lock_already = FALSE;
-          conn->mta_conn_mutex_unlock_later = FALSE;
-          DBUG_RETURN(spider_db_errorno(conn));
-        }
-      } else {
-        conn->mta_conn_mutex_lock_already = FALSE;
-        conn->mta_conn_mutex_unlock_later = FALSE;
-        SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-        pthread_mutex_unlock(&conn->mta_conn_mutex);
-        DBUG_RETURN(error_num);
-      }
-    }
-    st_spider_db_request_key request_key;
-    request_key.spider_thread_id = spider->trx->spider_thread_id;
-    request_key.query_id = spider->trx->thd->query_id;
-    request_key.handler = spider;
-    request_key.request_id = 1;
-    request_key.next = NULL;
-    if (!(res = conn->db_conn->store_result(NULL, &request_key, &error_num)))
-    {
-      conn->mta_conn_mutex_lock_already = FALSE;
-      conn->mta_conn_mutex_unlock_later = FALSE;
-      if (error_num || (error_num = spider_db_errorno(conn)))
-        DBUG_RETURN(error_num);
-      else {
-        my_printf_error(ER_SPIDER_REMOTE_TABLE_NOT_FOUND_NUM,
-          ER_SPIDER_REMOTE_TABLE_NOT_FOUND_STR, MYF(0),
-          oracle_share->db_names_str[spider->conn_link_idx[link_idx]].ptr(),
-          oracle_share->table_names_str[spider->conn_link_idx[
-            link_idx]].ptr());
-        DBUG_RETURN(ER_SPIDER_REMOTE_TABLE_NOT_FOUND_NUM);
-      }
-    }
-    conn->mta_conn_mutex_lock_already = FALSE;
-    conn->mta_conn_mutex_unlock_later = FALSE;
-    SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-    pthread_mutex_unlock(&conn->mta_conn_mutex);
-    error_num = res->fetch_table_status(
-      sts_mode,
-      share->records,
-      share->mean_rec_length,
-      share->data_file_length,
-      share->max_data_file_length,
-      share->index_file_length,
-      auto_increment_value,
-      share->create_time,
-      share->update_time,
-      share->check_time
-    );
-    res->free_result();
-    delete res;
-    if (error_num)
-      DBUG_RETURN(error_num);
-*/
     if (!share->stat.records)
       share->stat.records = 10000;
     share->stat.mean_rec_length = 65535;
@@ -11239,9 +11203,12 @@ int spider_oracle_handler::show_table_status(
     share->stat.update_time = (time_t) 0;
     share->stat.check_time = (time_t) 0;
   } else {
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
     pthread_mutex_lock(&conn->mta_conn_mutex);
     SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
     conn->need_mon = &spider->need_mons[link_idx];
+    DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = TRUE;
     conn->mta_conn_mutex_unlock_later = TRUE;
     spider_conn_set_timeout_from_share(conn, link_idx, spider->trx->thd,
@@ -11265,6 +11232,8 @@ int spider_oracle_handler::show_table_status(
         /* retry */
         if ((error_num = spider_db_ping(spider, conn, link_idx)))
         {
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -11273,6 +11242,8 @@ int spider_oracle_handler::show_table_status(
         }
         if ((error_num = spider_db_set_names(spider, conn, link_idx)))
         {
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -11288,11 +11259,15 @@ int spider_oracle_handler::show_table_status(
           -1,
           &spider->need_mons[link_idx])
         ) {
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           DBUG_RETURN(spider_db_errorno(conn));
         }
       } else {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -11308,6 +11283,8 @@ int spider_oracle_handler::show_table_status(
     request_key.next = NULL;
     if (!(res = conn->db_conn->store_result(NULL, &request_key, &error_num)))
     {
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       if (error_num || (error_num = spider_db_errorno(conn)))
@@ -11315,6 +11292,8 @@ int spider_oracle_handler::show_table_status(
       else
         DBUG_RETURN(ER_QUERY_ON_FOREIGN_DATA_SOURCE);
     }
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -11362,105 +11341,6 @@ int spider_oracle_handler::show_index(
   DBUG_PRINT("info",("spider crd_mode=%d", crd_mode));
   if (crd_mode == 1)
   {
-/*
-    pthread_mutex_lock(&conn->mta_conn_mutex);
-    SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
-    conn->need_mon = &spider->need_mons[link_idx];
-    conn->mta_conn_mutex_lock_already = TRUE;
-    conn->mta_conn_mutex_unlock_later = TRUE;
-    spider_conn_set_timeout_from_share(conn, link_idx, spider->trx->thd,
-      share);
-    if (
-      (error_num = spider_db_set_names(spider, conn, link_idx)) ||
-      (
-        spider_db_query(
-          conn,
-          oracle_share->show_index[0 + pos].ptr(),
-          oracle_share->show_index[0 + pos].length(),
-          -1,
-          &spider->need_mons[link_idx]) &&
-        (error_num = spider_db_errorno(conn))
-      )
-    ) {
-      if (
-        error_num == ER_SPIDER_REMOTE_SERVER_GONE_AWAY_NUM &&
-        !conn->disable_reconnect
-      ) {
-*/
-        /* retry */
-/*
-        if ((error_num = spider_db_ping(spider, conn, link_idx)))
-        {
-          conn->mta_conn_mutex_lock_already = FALSE;
-          conn->mta_conn_mutex_unlock_later = FALSE;
-          SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-          pthread_mutex_unlock(&conn->mta_conn_mutex);
-          DBUG_RETURN(error_num);
-        }
-        if ((error_num = spider_db_set_names(spider, conn, link_idx)))
-        {
-          conn->mta_conn_mutex_lock_already = FALSE;
-          conn->mta_conn_mutex_unlock_later = FALSE;
-          SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-          pthread_mutex_unlock(&conn->mta_conn_mutex);
-          DBUG_RETURN(error_num);
-        }
-        spider_conn_set_timeout_from_share(conn, link_idx, spider->trx->thd,
-          share);
-        if (spider_db_query(
-          conn,
-          oracle_share->show_index[0 + pos].ptr(),
-          oracle_share->show_index[0 + pos].length(),
-          -1,
-          &spider->need_mons[link_idx])
-        ) {
-          conn->mta_conn_mutex_lock_already = FALSE;
-          conn->mta_conn_mutex_unlock_later = FALSE;
-          DBUG_RETURN(spider_db_errorno(conn));
-        }
-      } else {
-        conn->mta_conn_mutex_lock_already = FALSE;
-        conn->mta_conn_mutex_unlock_later = FALSE;
-        SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-        pthread_mutex_unlock(&conn->mta_conn_mutex);
-        DBUG_RETURN(error_num);
-      }
-    }
-    st_spider_db_request_key request_key;
-    request_key.spider_thread_id = spider->trx->spider_thread_id;
-    request_key.query_id = spider->trx->thd->query_id;
-    request_key.handler = spider;
-    request_key.request_id = 1;
-    request_key.next = NULL;
-    if (!(res = conn->db_conn->store_result(NULL, &request_key, &error_num)))
-    {
-      if (error_num || (error_num = spider_db_errorno(conn)))
-      {
-        conn->mta_conn_mutex_lock_already = FALSE;
-        conn->mta_conn_mutex_unlock_later = FALSE;
-        SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-        pthread_mutex_unlock(&conn->mta_conn_mutex);
-        DBUG_RETURN(error_num);
-      }
-*/
-      /* no record is ok */
-/*
-    }
-    conn->mta_conn_mutex_lock_already = FALSE;
-    conn->mta_conn_mutex_unlock_later = FALSE;
-    SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
-    pthread_mutex_unlock(&conn->mta_conn_mutex);
-    if (res)
-    {
-      error_num = res->fetch_table_cardinality(
-        crd_mode,
-        table,
-        share->cardinality,
-        share->cardinality_upd,
-        share->bitmap_size
-      );
-    }
-*/
     for (roop_count = 0, tmp_cardinality = share->cardinality;
       roop_count < (int) table->s->fields;
       roop_count++, tmp_cardinality++)
@@ -11472,19 +11352,13 @@ int spider_oracle_handler::show_index(
         *tmp_cardinality = 1;
       }
     }
-/*
-    if (res)
-    {
-      res->free_result();
-      delete res;
-    }
-    if (error_num)
-      DBUG_RETURN(error_num);
-*/
   } else {
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
     pthread_mutex_lock(&conn->mta_conn_mutex);
     SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
     conn->need_mon = &spider->need_mons[link_idx];
+    DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = TRUE;
     conn->mta_conn_mutex_unlock_later = TRUE;
     spider_conn_set_timeout_from_share(conn, link_idx, spider->trx->thd,
@@ -11508,6 +11382,8 @@ int spider_oracle_handler::show_index(
         /* retry */
         if ((error_num = spider_db_ping(spider, conn, link_idx)))
         {
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -11516,6 +11392,8 @@ int spider_oracle_handler::show_index(
         }
         if ((error_num = spider_db_set_names(spider, conn, link_idx)))
         {
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -11531,11 +11409,15 @@ int spider_oracle_handler::show_index(
           -1,
           &spider->need_mons[link_idx])
         ) {
+          DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+          DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
           conn->mta_conn_mutex_lock_already = FALSE;
           conn->mta_conn_mutex_unlock_later = FALSE;
           DBUG_RETURN(spider_db_errorno(conn));
         }
       } else {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -11553,6 +11435,8 @@ int spider_oracle_handler::show_index(
     {
       if (error_num || (error_num = spider_db_errorno(conn)))
       {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -11561,6 +11445,8 @@ int spider_oracle_handler::show_index(
       }
       /* no record is ok */
     }
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -11606,9 +11492,12 @@ int spider_oracle_handler::show_records(
   SPIDER_SHARE *share = spider->share;
   uint pos = spider->conn_link_idx[link_idx];
   DBUG_ENTER("spider_oracle_handler::show_records");
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
   pthread_mutex_lock(&conn->mta_conn_mutex);
   SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
   conn->need_mon = &spider->need_mons[link_idx];
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = TRUE;
   conn->mta_conn_mutex_unlock_later = TRUE;
   spider_conn_set_timeout_from_share(conn, link_idx, spider->trx->thd,
@@ -11632,6 +11521,8 @@ int spider_oracle_handler::show_records(
       /* retry */
       if ((error_num = spider_db_ping(spider, conn, link_idx)))
       {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -11641,6 +11532,8 @@ int spider_oracle_handler::show_records(
       }
       if ((error_num = spider_db_set_names(spider, conn, link_idx)))
       {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -11657,12 +11550,16 @@ int spider_oracle_handler::show_records(
         -1,
         &spider->need_mons[link_idx])
       ) {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         DBUG_PRINT("info", ("spider error_num=%d 3", error_num));
         DBUG_RETURN(spider_db_errorno(conn));
       }
     } else {
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -11679,18 +11576,29 @@ int spider_oracle_handler::show_records(
   request_key.next = NULL;
   if (!(res = conn->db_conn->store_result(NULL, &request_key, &error_num)))
   {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
-    if (error_num || (error_num = spider_db_errorno(conn)))
+    if (error_num)
     {
+      SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+      pthread_mutex_unlock(&conn->mta_conn_mutex);
       DBUG_PRINT("info", ("spider error_num=%d 5", error_num));
       DBUG_RETURN(error_num);
+    }
+    else if (error_num || (error_num = spider_db_errorno(conn)))
+    {
+      DBUG_PRINT("info", ("spider error_num=%d 6", error_num));
+      DBUG_RETURN(error_num);
     } else {
-      DBUG_PRINT("info", ("spider error_num=%d 6",
+      DBUG_PRINT("info", ("spider error_num=%d 7",
         ER_QUERY_ON_FOREIGN_DATA_SOURCE));
       DBUG_RETURN(ER_QUERY_ON_FOREIGN_DATA_SOURCE);
     }
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = FALSE;
   conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -11723,9 +11631,12 @@ int spider_oracle_handler::show_autoinc(
   if (!oracle_share->show_autoinc)
     DBUG_RETURN(0);
 
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
   pthread_mutex_lock(&conn->mta_conn_mutex);
   SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
   conn->need_mon = &spider->need_mons[link_idx];
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = TRUE;
   conn->mta_conn_mutex_unlock_later = TRUE;
   spider_conn_set_timeout_from_share(conn, link_idx, spider->trx->thd,
@@ -11749,6 +11660,8 @@ int spider_oracle_handler::show_autoinc(
       /* retry */
       if ((error_num = spider_db_ping(spider, conn, link_idx)))
       {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -11758,6 +11671,8 @@ int spider_oracle_handler::show_autoinc(
       }
       if ((error_num = spider_db_set_names(spider, conn, link_idx)))
       {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -11774,12 +11689,16 @@ int spider_oracle_handler::show_autoinc(
         -1,
         &spider->need_mons[link_idx])
       ) {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         DBUG_PRINT("info", ("spider error_num=%d 3", error_num));
         DBUG_RETURN(spider_db_errorno(conn));
       }
     } else {
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -11796,18 +11715,29 @@ int spider_oracle_handler::show_autoinc(
   request_key.next = NULL;
   if (!(res = conn->db_conn->store_result(NULL, &request_key, &error_num)))
   {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
-    if (error_num || (error_num = spider_db_errorno(conn)))
+    if (error_num)
     {
+      SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+      pthread_mutex_unlock(&conn->mta_conn_mutex);
       DBUG_PRINT("info", ("spider error_num=%d 5", error_num));
       DBUG_RETURN(error_num);
+    }
+    else if ((error_num = spider_db_errorno(conn)))
+    {
+      DBUG_PRINT("info", ("spider error_num=%d 6", error_num));
+      DBUG_RETURN(error_num);
     } else {
-      DBUG_PRINT("info", ("spider error_num=%d 6",
+      DBUG_PRINT("info", ("spider error_num=%d 7",
         ER_QUERY_ON_FOREIGN_DATA_SOURCE));
       DBUG_RETURN(ER_QUERY_ON_FOREIGN_DATA_SOURCE);
     }
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = FALSE;
   conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -11917,9 +11847,12 @@ ha_rows spider_oracle_handler::explain_select(
     DBUG_RETURN(HA_POS_ERROR);
   }
 
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
   pthread_mutex_lock(&conn->mta_conn_mutex);
   SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
   conn->need_mon = &spider->need_mons[link_idx];
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = TRUE;
   conn->mta_conn_mutex_unlock_later = TRUE;
   spider_conn_set_timeout_from_share(conn, link_idx, spider->trx->thd,
@@ -11945,6 +11878,8 @@ ha_rows spider_oracle_handler::explain_select(
       {
         if (spider->check_error_mode(error_num))
           my_errno = error_num;
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -11955,6 +11890,8 @@ ha_rows spider_oracle_handler::explain_select(
       {
         if (spider->check_error_mode(error_num))
           my_errno = error_num;
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -11973,6 +11910,8 @@ ha_rows spider_oracle_handler::explain_select(
         error_num = spider_db_errorno(conn);
         if (spider->check_error_mode(error_num))
           my_errno = error_num;
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -11982,6 +11921,8 @@ ha_rows spider_oracle_handler::explain_select(
     } else {
       if (spider->check_error_mode(error_num))
         my_errno = error_num;
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -12001,6 +11942,8 @@ ha_rows spider_oracle_handler::explain_select(
     {
       if (spider->check_error_mode(error_num))
         my_errno = error_num;
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -12008,6 +11951,8 @@ ha_rows spider_oracle_handler::explain_select(
       DBUG_RETURN(HA_POS_ERROR);
     } else {
       my_errno = ER_QUERY_ON_FOREIGN_DATA_SOURCE;
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -12015,6 +11960,8 @@ ha_rows spider_oracle_handler::explain_select(
       DBUG_RETURN(HA_POS_ERROR);
     }
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = FALSE;
   conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -12048,13 +11995,18 @@ int spider_oracle_handler::lock_tables(
     }
     if (str->length())
     {
+      pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
       pthread_mutex_lock(&conn->mta_conn_mutex);
       SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
       conn->need_mon = &spider->need_mons[link_idx];
+      DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = TRUE;
       conn->mta_conn_mutex_unlock_later = TRUE;
       if ((error_num = spider_db_set_names(spider, conn, link_idx)))
       {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -12070,10 +12022,14 @@ int spider_oracle_handler::lock_tables(
         -1,
         &spider->need_mons[link_idx])
       ) {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         DBUG_RETURN(spider_db_errorno(conn));
       }
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -12119,13 +12075,18 @@ int spider_oracle_handler::disable_keys(
   {
     DBUG_RETURN(error_num);
   }
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
   pthread_mutex_lock(&conn->mta_conn_mutex);
   SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
   conn->need_mon = &spider->need_mons[link_idx];
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = TRUE;
   conn->mta_conn_mutex_unlock_later = TRUE;
   if ((error_num = spider_db_set_names(spider, conn, link_idx)))
   {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -12141,11 +12102,15 @@ int spider_oracle_handler::disable_keys(
     -1,
     &spider->need_mons[link_idx])
   ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     error_num = spider_db_errorno(conn);
     DBUG_RETURN(error_num);
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = FALSE;
   conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -12168,13 +12133,18 @@ int spider_oracle_handler::enable_keys(
   {
     DBUG_RETURN(error_num);
   }
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
   pthread_mutex_lock(&conn->mta_conn_mutex);
   SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
   conn->need_mon = &spider->need_mons[link_idx];
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = TRUE;
   conn->mta_conn_mutex_unlock_later = TRUE;
   if ((error_num = spider_db_set_names(spider, conn, link_idx)))
   {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -12190,11 +12160,15 @@ int spider_oracle_handler::enable_keys(
     -1,
     &spider->need_mons[link_idx])
   ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     error_num = spider_db_errorno(conn);
     DBUG_RETURN(error_num);
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = FALSE;
   conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -12218,13 +12192,18 @@ int spider_oracle_handler::check_table(
   {
     DBUG_RETURN(error_num);
   }
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
   pthread_mutex_lock(&conn->mta_conn_mutex);
   SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
   conn->need_mon = &spider->need_mons[link_idx];
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = TRUE;
   conn->mta_conn_mutex_unlock_later = TRUE;
   if ((error_num = spider_db_set_names(spider, conn, link_idx)))
   {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -12240,11 +12219,15 @@ int spider_oracle_handler::check_table(
     -1,
     &spider->need_mons[link_idx])
   ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     error_num = spider_db_errorno(conn);
     DBUG_RETURN(error_num);
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = FALSE;
   conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -12268,13 +12251,18 @@ int spider_oracle_handler::repair_table(
   {
     DBUG_RETURN(error_num);
   }
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
   pthread_mutex_lock(&conn->mta_conn_mutex);
   SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
   conn->need_mon = &spider->need_mons[link_idx];
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = TRUE;
   conn->mta_conn_mutex_unlock_later = TRUE;
   if ((error_num = spider_db_set_names(spider, conn, link_idx)))
   {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -12290,11 +12278,15 @@ int spider_oracle_handler::repair_table(
     -1,
     &spider->need_mons[link_idx])
   ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     error_num = spider_db_errorno(conn);
     DBUG_RETURN(error_num);
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = FALSE;
   conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -12317,13 +12309,18 @@ int spider_oracle_handler::analyze_table(
   {
     DBUG_RETURN(error_num);
   }
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
   pthread_mutex_lock(&conn->mta_conn_mutex);
   SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
   conn->need_mon = &spider->need_mons[link_idx];
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = TRUE;
   conn->mta_conn_mutex_unlock_later = TRUE;
   if ((error_num = spider_db_set_names(spider, conn, link_idx)))
   {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -12339,11 +12336,15 @@ int spider_oracle_handler::analyze_table(
     -1,
     &spider->need_mons[link_idx])
   ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     error_num = spider_db_errorno(conn);
     DBUG_RETURN(error_num);
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = FALSE;
   conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -12366,13 +12367,18 @@ int spider_oracle_handler::optimize_table(
   {
     DBUG_RETURN(error_num);
   }
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
   pthread_mutex_lock(&conn->mta_conn_mutex);
   SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
   conn->need_mon = &spider->need_mons[link_idx];
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = TRUE;
   conn->mta_conn_mutex_unlock_later = TRUE;
   if ((error_num = spider_db_set_names(spider, conn, link_idx)))
   {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -12388,11 +12394,15 @@ int spider_oracle_handler::optimize_table(
     -1,
     &spider->need_mons[link_idx])
   ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     error_num = spider_db_errorno(conn);
     DBUG_RETURN(error_num);
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
   conn->mta_conn_mutex_lock_already = FALSE;
   conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -12418,6 +12428,14 @@ int spider_oracle_handler::flush_tables(
   }
   spider_conn_set_timeout_from_share(conn, link_idx, spider->trx->thd,
     share);
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+  pthread_mutex_lock(&conn->mta_conn_mutex);
+  SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+  conn->need_mon = &spider->need_mons[link_idx];
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = TRUE;
+  conn->mta_conn_mutex_unlock_later = TRUE;
   if (spider_db_query(
     conn,
     str->ptr(),
@@ -12425,9 +12443,17 @@ int spider_oracle_handler::flush_tables(
     -1,
     &spider->need_mons[link_idx])
   ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = FALSE;
+    conn->mta_conn_mutex_unlock_later = FALSE;
     error_num = spider_db_errorno(conn);
     DBUG_RETURN(error_num);
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = FALSE;
+  conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
   pthread_mutex_unlock(&conn->mta_conn_mutex);
   DBUG_RETURN(0);
@@ -12443,6 +12469,14 @@ int spider_oracle_handler::flush_logs(
   DBUG_PRINT("info",("spider this=%p", this));
   spider_conn_set_timeout_from_share(conn, link_idx, spider->trx->thd,
     share);
+  pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
+  pthread_mutex_lock(&conn->mta_conn_mutex);
+  SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
+  conn->need_mon = &spider->need_mons[link_idx];
+  DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = TRUE;
+  conn->mta_conn_mutex_unlock_later = TRUE;
   if (spider_db_query(
     conn,
     SPIDER_SQL_FLUSH_LOGS_STR,
@@ -12450,9 +12484,17 @@ int spider_oracle_handler::flush_logs(
     -1,
     &spider->need_mons[link_idx])
   ) {
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+    conn->mta_conn_mutex_lock_already = FALSE;
+    conn->mta_conn_mutex_unlock_later = FALSE;
     error_num = spider_db_errorno(conn);
     DBUG_RETURN(error_num);
   }
+  DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+  DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
+  conn->mta_conn_mutex_lock_already = FALSE;
+  conn->mta_conn_mutex_unlock_later = FALSE;
   SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
   pthread_mutex_unlock(&conn->mta_conn_mutex);
   DBUG_RETURN(0);
diff --git a/storage/spider/spd_group_by_handler.cc b/storage/spider/spd_group_by_handler.cc
index caa974bf8ee..de041897239 100644
--- a/storage/spider/spd_group_by_handler.cc
+++ b/storage/spider/spd_group_by_handler.cc
@@ -1410,6 +1410,7 @@ int spider_group_by_handler::init_scan()
       }
     } else {
 #endif
+      pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
       if (dbton_hdl->need_lock_before_set_sql_for_exec(
         SPIDER_SQL_TYPE_SELECT_SQL))
       {
@@ -1420,6 +1421,12 @@ int spider_group_by_handler::init_scan()
         dbton_hdl->set_sql_for_exec(SPIDER_SQL_TYPE_SELECT_SQL, link_idx,
         link_idx_chain)))
       {
+        if (dbton_hdl->need_lock_before_set_sql_for_exec(
+          SPIDER_SQL_TYPE_SELECT_SQL))
+        {
+          SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
+          pthread_mutex_unlock(&conn->mta_conn_mutex);
+        }
         DBUG_RETURN(error_num);
       }
       if (!dbton_hdl->need_lock_before_set_sql_for_exec(
@@ -1429,11 +1436,15 @@ int spider_group_by_handler::init_scan()
         SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
       }
       conn->need_mon = &spider->need_mons[link_idx];
+      DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = TRUE;
       conn->mta_conn_mutex_unlock_later = TRUE;
       if ((error_num = spider_db_set_names(spider, conn,
         link_idx)))
       {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -1458,6 +1469,8 @@ int spider_group_by_handler::init_scan()
         spider->result_list.quick_mode,
         &spider->need_mons[link_idx])
       ) {
+        DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+        DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
         conn->mta_conn_mutex_lock_already = FALSE;
         conn->mta_conn_mutex_unlock_later = FALSE;
         error_num = spider_db_errorno(conn);
@@ -1474,6 +1487,8 @@ int spider_group_by_handler::init_scan()
         DBUG_RETURN(error_num);
       }
       spider->connection_ids[link_idx] = conn->connection_id;
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       if (fields->is_first_link_ok_chain(link_idx_chain))
diff --git a/storage/spider/spd_include.h b/storage/spider/spd_include.h
index 2249d3e699c..95064fa4c72 100644
--- a/storage/spider/spd_include.h
+++ b/storage/spider/spd_include.h
@@ -19,6 +19,8 @@
 
 #if MYSQL_VERSION_ID < 50500
 #define spider_my_free(A,B) my_free(A,B)
+#define pthread_mutex_assert_owner(A)
+#define pthread_mutex_assert_not_owner(A)
 #else
 #define spider_my_free(A,B) my_free(A)
 #ifdef pthread_mutex_t
@@ -41,6 +43,8 @@
 #undef pthread_mutex_destroy
 #endif
 #define pthread_mutex_destroy mysql_mutex_destroy
+#define pthread_mutex_assert_owner(A) mysql_mutex_assert_owner(A)
+#define pthread_mutex_assert_not_owner(A) mysql_mutex_assert_not_owner(A)
 #ifdef pthread_cond_t
 #undef pthread_cond_t
 #endif
diff --git a/storage/spider/spd_table.cc b/storage/spider/spd_table.cc
index 88effd38717..fd0ece10c1b 100644
--- a/storage/spider/spd_table.cc
+++ b/storage/spider/spd_table.cc
@@ -6383,13 +6383,18 @@ int spider_open_all_tables(
     }
     conn->error_mode &= spider_param_error_read_mode(thd, 0);
     conn->error_mode &= spider_param_error_write_mode(thd, 0);
+    pthread_mutex_assert_not_owner(&conn->mta_conn_mutex);
     pthread_mutex_lock(&conn->mta_conn_mutex);
     SPIDER_SET_FILE_POS(&conn->mta_conn_mutex_file_pos);
     conn->need_mon = &mon_val;
+    DBUG_ASSERT(!conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(!conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = TRUE;
     conn->mta_conn_mutex_unlock_later = TRUE;
     if ((error_num = spider_db_before_query(conn, &mon_val)))
     {
+      DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+      DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
       conn->mta_conn_mutex_lock_already = FALSE;
       conn->mta_conn_mutex_unlock_later = FALSE;
       SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);
@@ -6402,6 +6407,8 @@ int spider_open_all_tables(
       free_root(&mem_root, MYF(0));
       DBUG_RETURN(error_num);
     }
+    DBUG_ASSERT(conn->mta_conn_mutex_lock_already);
+    DBUG_ASSERT(conn->mta_conn_mutex_unlock_later);
     conn->mta_conn_mutex_lock_already = FALSE;
     conn->mta_conn_mutex_unlock_later = FALSE;
     SPIDER_CLEAR_FILE_POS(&conn->mta_conn_mutex_file_pos);