diff --git a/client/mysql.cc b/client/mysql.cc
index 90c14087fed..81a81eb8d6f 100644
--- a/client/mysql.cc
+++ b/client/mysql.cc
@@ -1174,7 +1174,7 @@ int main(int argc,char *argv[])
 
   put_info("Welcome to the MariaDB monitor.  Commands end with ; or \\g.",
 	   INFO_INFO);
-  sprintf((char*) glob_buffer.ptr(),
+  my_snprintf((char*) glob_buffer.ptr(), glob_buffer.alloced_length(),
 	  "Your %s connection id is %lu\nServer version: %s\n",
           mysql_get_server_name(&mysql),
 	  mysql_thread_id(&mysql), server_version_string(&mysql));
diff --git a/sql/sql_base.cc b/sql/sql_base.cc
index 8a8ba1f18d5..1e3733cb498 100644
--- a/sql/sql_base.cc
+++ b/sql/sql_base.cc
@@ -7875,12 +7875,9 @@ bool setup_tables(THD *thd, Name_resolution_context *context,
     {
       DBUG_ASSERT(table_list->view &&
                   table_list->effective_algorithm == VIEW_ALGORITHM_MERGE);
-      Query_arena *arena= thd->stmt_arena, backup;
+      Query_arena *arena, backup;
+      arena= thd->activate_stmt_arena_if_needed(&backup);
       bool res;
-      if (arena->is_conventional())
-        arena= 0;                                   // For easier test
-      else
-        thd->set_n_backup_active_arena(arena, &backup);
       res= table_list->setup_underlying(thd);
       if (arena)
         thd->restore_active_arena(arena, &backup);
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 3641b14183b..156020bff55 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -882,11 +882,8 @@ JOIN::optimize()
       MEMROOT for prepared statements and stored procedures.
     */
 
-    Query_arena *arena= thd->stmt_arena, backup;
-    if (arena->is_conventional())
-      arena= 0;                                   // For easier test
-    else
-      thd->set_n_backup_active_arena(arena, &backup);
+    Query_arena *arena, backup;
+    arena= thd->activate_stmt_arena_if_needed(&backup);
 
     sel->first_cond_optimization= 0;
 
diff --git a/sql/sql_view.cc b/sql/sql_view.cc
index 0fe1b597d82..6809f0da148 100644
--- a/sql/sql_view.cc
+++ b/sql/sql_view.cc
@@ -1121,11 +1121,7 @@ bool mysql_make_view(THD *thd, File_parser *parser, TABLE_LIST *table,
     will be TRUE as far as we make new table cache).
   */
   old_lex= thd->lex;
-  arena= thd->stmt_arena;
-  if (arena->is_conventional())
-    arena= 0;
-  else
-    thd->set_n_backup_active_arena(arena, &backup);
+  arena= thd->activate_stmt_arena_if_needed(&backup);
 
   /* init timestamp */
   if (!table->timestamp.str)