Wouldn't it be nice if we could use UPDATE DELAYED in mysql just like we do use INSERT DELAYED? Unfortunately, the work around mysql created for this is to insert a record into the events table in order to separate UPDATE statement into another thread. There is a large overhead to inserting to then execute an update.

If you are using PHP with mysql, there is another work around.  PHP has a function called, register_shutdown_function, which will execute a function during the shutdown of processing a script file. So if we add an UPDATE LOW_PRIORITY sql statement wrapped in a function that is passed to register_shutdown_function, we can allow the user to receive the page without delay while the UPDATE statement waits until all locks on the table has been release before proceeding.

function update_delayed()
{
$sql = "UPDATE LOW_PRIORITY table_name SET col1 = 'something'";
mysql_query($sql, $conn);
}

register_shutdown_function('update_delayed');


I wonder if there are even better ways to handle this problem.

I found that using php function, strip_tags, does not remove all the markup elements correctly from the subject content.  First of all, if an anchor link includes a line break, it will not be removed correctly.  Also, the style information is not properly removed as well.  In the following script, I also added in the regex to remove any content in between script tags, but that may or may not be necessary.

function strip_all_tags($content)
{
$content = preg_replace('/\n/',' ',$content);
$content = preg_replace('/<script.*<\/script>/U',' ',$content);
$content = preg_replace('/<style.*<\/style>/U',' ',$content);
$content = strip_tags(strtolower($content));
return $content;
}

The function will remove all line breaks so strip_tags will not have problems with finding all markups.  Since strip_tags does not remove <style> tags, the new function will remove them using regex.