Implementation of long connection in PHP

Recently, I encountered a PHP program prompting a timeout when executing a large amount of data, so I used the set_time_limit() function to set the maximum running time of the PHP page.
Set the number of seconds the script is allowed to run. If this is the default, the script returns a fatal error. The default limit is 30 seconds, or you can set the maximum execution time of the PHP page by defining max_execution_time in php.ini.
When called, the set_time_limit() function restarts the timeout counter from zero. In other words, if the timeout is 30 seconds by default, 25 seconds to the script's execution parameter or set_time_limit, if the timeout is set to (20), the script will run for 45 seconds before timing out.
set_time_limit(900) This function specifies the maximum execution time of the current php script. Although the set value is 900 seconds, the actual maximum execution time = the max_execution_time value in php.ini - the execution time of the current script + the set value.
If max_execution_time=30 in php.ini and the current script has been executed for 10 seconds, then:
Maximum execution time=30-10+900=920 seconds.
After such modification, the PHP script successfully updated 200,000 records.
Every time we access a PHP script, we only get the return result after all PHP scripts have been executed. If we need a script to run continuously, then we must use PHP long connection to achieve the purpose of operation.

Every PHP script has a limited execution time, so we need to set the execution time of a script to unlimited through set_time_limit; then use flush() and ob_flush() to clear the server buffer and output the return value of the script at any time.

<?php
header("Content-Type: text/plain");
set_time_limit(0);

$infoString = "Hello World" . "\n";
while( isset($infoString) )
{
echo $infoString;
flush();
ob_flush();
sleep(5);
}
?>

The above introduces the implementation of long connections in PHP, including aspects of it. I hope it will be helpful to friends who are interested in PHP tutorials.