diff --git a/sql/sql_class.cc b/sql/sql_class.cc
index ba7e0654331..0db3ea22c78 100644
--- a/sql/sql_class.cc
+++ b/sql/sql_class.cc
@@ -1188,11 +1188,11 @@ void add_to_status(STATUS_VAR *to_var, STATUS_VAR *from_var)
     *(to++)+= *(from++);
 
   /* Handle the not ulong variables. See end of system_status_var */
-  to_var->bytes_received=       from_var->bytes_received;
+  to_var->bytes_received+=      from_var->bytes_received;
   to_var->bytes_sent+=          from_var->bytes_sent;
   to_var->rows_read+=           from_var->rows_read;
   to_var->rows_sent+=           from_var->rows_sent;
-  to_var->binlog_bytes_written= from_var->binlog_bytes_written;
+  to_var->binlog_bytes_written+= from_var->binlog_bytes_written;
   to_var->cpu_time+=            from_var->cpu_time;
   to_var->busy_time+=           from_var->busy_time;
 }
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 287f08bad44..9d2298e4675 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -11009,10 +11009,21 @@ static bool create_internal_tmp_table(TABLE *table,TMP_TABLE_PARAM *param,
       OPTION_BIG_TABLES)
     create_info.data_file_length= ~(ulonglong) 0;
 
+  /*
+    The logic for choosing the record format:
+    The STATIC_RECORD format is the fastest one, because it's so simple,
+    so we use this by default for short rows.
+    BLOCK_RECORD caches both row and data, so this is generally faster than
+    DYNAMIC_RECORD. The one exception is when we write to tmp table
+    (no updates == no sum fields) in which case BLOCK RECORD is slower as
+    we first write the row, then check for key conflicts and then we have to
+    delete the row.
+  */
   if ((error= maria_create(share->table_name.str,
-                           share->reclength < 64 &&
-                           !share->blob_fields ? STATIC_RECORD :
-                           BLOCK_RECORD,
+                           (share->reclength < 64 &&
+                            !share->blob_fields ? STATIC_RECORD :
+                            !param->sum_func_count ? DYNAMIC_RECORD :
+                            BLOCK_RECORD),
                            share->keys, &keydef,
                            (uint) (param->recinfo-param->start_recinfo),
                            param->start_recinfo,