set_time_limit() counts time while pg_get_result() waiting for asynchronous PostgreSQL query

[lezso6]

Description

The following code:

<?php
// Connect
$conn = pg_connect("dbname='somedb'");
// Send a postgres sleep query (or anything long running query)
pg_send_query($conn, "SELECT pg_sleep(5)");
// Set PHP max execution time less than above
set_time_limit(2);
// Waiting for query to complete (but fails and error is shown)
$res = pg_get_result($conn); 
// Never printed
echo "OK"; 

Resulted in this output:

PHP Fatal error: maximum execution time of 2 seconds exceeded

But I expected this output instead:

OK

PHP Version

8.3.8

Operating System

Gentoo Linux

[lezso6]

The code worked as expected in PHP 8.1, until I upgraded to PHP 8.3. I think it should not count time while the PHP script is doing nothing but waiting for the PostgreSQL server. I did not find any documentation about this change in code behaviour.

[devnexen]

I have tried with the following cases :

• last master built on ubuntu 24.04 on local pgsql server.
• 8.3.6 from same ubuntu with same server.
• 8.3.8 from macOs remote connection on this same pgsql server.

In every case I get my OK.

[lezso6]

Thanks for the quick reply. Indeed, the code works as it should on Ubuntu, I tried it too. I have two very different Gentoo systems with PHP 8.3 and both produces the bug. I also tested PHP 8.2 on Gentoo (same configuration) and got the OK. It's weird, seems like a Gentoo specific bug on version 8.3.

[MorganLOCode]

As another datapoint, 8.3.8 on Windows times out as well.

[lezso6]

I tried version 8.3.6 and 8.3.3 on Gentoo and both throws the error.

[lezso6]

I think I found the problem, the error depends on whether thread safety is enabled or not. If I compile PHP 8.3.8 on Gentoo without threads, the above code works as should. But if I compile PHP with POSIX threads, the code breaks. On Ubuntu the PHP 8.3.6 is compiled without threads, that's why it's working okay.

[devnexen]

does it work with ZTS and in a non async way ? e.g. just pg_query

[lezso6]

Suprisingly, the script times out in non-async / blocking mode too:

<?php
$conn = pg_connect("host='127.0.0.1' port='5432' dbname='template1' user='postgres'");
ini_set('display_errors', '1');
// Setting execution time less than below
set_time_limit(2);
// PHP Fatal error: maximum execution time of 2 seconds exceeded
pg_query($conn, "SELECT pg_sleep(5)");
// Never printed
echo "OK";

[devnexen]

I ll have a look in the following days.

[devnexen]

Anybody using mysql ? If yes what happens with ZTS build with 'SELECT SLEEP(5)' query?

[lezso6]

I tried mysqli extension with MariaDB and the PHP script times out as well. Code:

<?php
ini_set('display_errors', '1');
echo PHP_VERSION . "\n";
$conn = mysqli_connect('127.0.0.1', 'root', '1234');
// Setting execution time less than SLEEP()
set_time_limit(2);
// PHP Fatal error: maximum execution time of 2 seconds exceeded
mysqli_query($conn, "SELECT SLEEP(5)");
// Never printed
echo "OK"; 

[lezso6]

Even PHP's sleep() function times out with ZTS enabled:

<?php
ini_set('display_errors', '1');
echo PHP_VERSION . "\n";
// Setting execution time less than PHP sleep()
set_time_limit(2);
// PHP Fatal error: maximum execution time of 2 seconds exceeded
sleep(5);
// Never printed
echo "OK"; 

Without ZTS, there is no timeout.

[devnexen]

Ok gonna bisect it. I think that s better support Linux timeouts with ZTS part but will double-check.

[devnexen]

Was wrong about the commit, @lezso6, if you build from source, can you add --enable-zend-max-execution-timers=no to the ./configure command ? I forgot about that change ..

[lezso6]

I recompiled with ZTS enabled and Zend Max Execution Timers disabled, and the bug is gone. It works, no timeouts.

[devnexen]

It appears on the migration guide. Distribution packagers would need to modify their build workflow to take it into account.

[lezso6]

So if I understand correctly, this is a feature. And will be enabled for non-ZTS builds, I read that here: #6504 (comment)