date_default_timezone_get 有时加载缓慢

Question

I am not sure why we added in the below to set the timezone but maybe 1 out of every 100 calls to date_default_timezone_get can take 5+ milliseconds to load. Does anyone have any information on why this would sometimes run slow? Servers are running on Google Cloud CentOS Linux 7 with PHP Version 5.6.40 (Yes I know it needs updated)

// LOAD TIME: 1.692ms
if (!date_default_timezone_get('date.timezone'))    {
    // NEVERHIT
    date_default_timezone_set('America/Chicago');
    // LOAD TIME: 6.794ms
}

Answer 1

The line

if (!date_default_timezone_get('date.timezone'))    {

generates the warning

Warning: date_default_timezone_get() expects exactly 0 parameters, 1 given in..

That takes a lot of time. An if condition that is always true also makes no sense. The instruction

date_default_timezone_set('America/Chicago');

only takes a fraction of the time from instruction that generats warnings. The date_default_timezone_set() command should always be executed if there are uncertainties about the time zone of the environment.