PHP/MySQL - Run actions from background / Dealing with a longer-running method - php

Question

I have a form in PHP that saves some data into a database. However, after a successful insert, the PHP function below executes to arrange every entry by a "visible" ID column (called correlativo in this case).
function ordenar_ids()
{
$sql = "SELECT DISTINCT(DATE_FORMAT(fecha, '%Y')) FROM emergencias ORDER BY fecha";
$results = mysql_query($sql);
$anios = [];
while ($row = mysql_fetch_array($results))
array_push($anios, $row[0]);
foreach($anios as $anio)
{
$sql = "SELECT id_emergencia FROM emergencias WHERE fecha LIKE '".$anio."%' ORDER BY fecha ASC;";
$results = mysql_query($sql);
$correlativo = 1;
while ($row = mysql_fetch_array($results))
{
$sql = "UPDATE emergencias SET correlativo = $correlativo WHERE id_emergencia = '".$row[0]."';";
mysql_query($sql);
$correlativo++;
}
}
return 1;
}
Initial (local) tests were successful, however when we tested this in a production environment we noticed this process is taking way too long (about 15 seconds on average) which is detrimental to the user experience.
Is it possible to run this function in the background after the user has submitted the form? If it's not possible, how can we work around this problem?
Additional Data:
The user doesn't need a return value of this function, nor it's needed for the following actions that happens after.

Answer 1

You can't easily run a mysql query in the background. But xou could start a new php script in background: http://php.net/manual/de/function.exec.php#86329
But better would be to improve the script performance itself. I think, you can improve it by using one "update ... select" query, avoiding LIKE % or using mysql triggers.