PHP max_execution_time, what is the best tune for large uploaded files

PHPphp5uploadWordpress

I have a WordPress installed and I use a web form to upload images in my web site. The web form allowing the end user to upload more than one files at a time.

The problem is that one of my users had that error :

Fatal error: Maximum execution time of 30 seconds exceeded in /home/ACOUNT/public_html/wp-includes/media.php on line 258

So what is the best tuning for max_execution_time. Now as you can see is 30 seconds. Any idea please?

If I set that in a very high value (ie 600) will that affect my server performance ?

Note: the user had try to upload two files, with sizes of 2.96MB and 2.9MB.

Kind regards
Merianos Nikos

Best Answer

I'm guessing from the path in the error message that this is a Unix/Linux system (MSWindows handles the timeout very differently).

While bandwidth (and latency!) has a big impact on the time taken to process the request, the PHP clock only starts when the PHP interpreter is invoked - this won't be until the webserver has received a complete request - i.e. the PHP execution time and hence the timeout should have nothing to do with how long it took for the webserver to process the request.

There is a timeout in PHP to determine how long it should spend receiving data from the webserver - max_input_time - and it has been reported that when this is exceeded it reports max_execution_time exceeded!.

So....assuming a 0 latency network...

  • 00:00 user starts upload, apache timeout clock starts (but will keep getting reset by new packets arriving)

  • 00:10 receiving of request completed by Apache, request handed over to PHP, max_input_time clock started

  • 00:11 PHP has read all the input, max_input_time clock is stopped, max_execution_time clock started, script is executed

Now since on a Unix box, the max_execution clock only ticks when the PHP is executing, the problem is with PHP's performance / the performance of the PHP script.

Yes, you can increase the max execution time without it having a big impact elsewhere (although setting it via ini_set() / set_time_limit() on a script by script basis is neater than a global setting). But do make sure you're using an opcode cache, and if the php script is trying to parse the data, do beware of data / parser issues.

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