Method init

storage/perfschema/pfs_variable.cc:505–555

Get sys_var value from global or local source then convert to string. */

  Get sys_var value from global or local source then convert to string.
*/
void System_variable::init(THD *target_thd, const SHOW_VAR *show_var,
                           enum_var_type query_scope)
{
  if (show_var == NULL || show_var->name == NULL)
    return;

  DBUG_ASSERT(show_var->type == SHOW_SYS);

  m_name= show_var->name;
  m_name_length= strlen(m_name);

  /* Deprecated variables are ignored but must still be accounted for. */
  if (m_ignore)
  {
    m_value_str[0]= '\0';
    m_value_length= 0;
    m_initialized= true;
    return;
  }

  /* Block remote target thread from updating this system variable. */
  /*XXX
  THD *current_thread= current_thd;
  if (target_thd != current_thread)
    mysql_mutex_lock(&target_thd->LOCK_thd_sysvar);*/

  sys_var *system_var= (sys_var *)show_var->value;
  assert(system_var != NULL);
  m_charset= system_var->charset(target_thd);
  m_type= system_var->show_type();
  m_scope= system_var->scope();

  /* Get the value of the system variable. */
  String buf(m_value_str, sizeof(m_value_str) - 1, system_charset_info);
  if (!system_var->val_str_nolock(&buf, target_thd,
               system_var->value_ptr(target_thd, query_scope, &null_clex_str)))
    buf.length(0);

  m_value_length= MY_MIN(buf.length(), SHOW_VAR_FUNC_BUFF_SIZE);

  /* Returned value may reference a string other than m_value_str. */
  if (buf.ptr() != m_value_str)
    memcpy(m_value_str, buf.ptr(), m_value_length);
  m_value_str[m_value_length]= 0;

  /*XXX
  if (target_thd != current_thread)
    mysql_mutex_unlock(&target_thd->LOCK_thd_sysvar);*/

  m_initialized= true;
}


/**