[4.0] Query explain feature is broken due to DB changes, and queryMonitor limitation

[Fedik]

Steps to reproduce the issue

Enable debug plugin and enable "Query explain" feature.
In the Debugbar, in Query tab you should be able to see Explain , near the every "select" query.
But it show empty table. @alikon comment: #25675 (comment)

The reasons

The reasons is that the plugin run EXPLAIN without required params, and so database return SQL error.

joomla-cms/plugins/system/debug/debug.php

Lines 524 to 529 in e5db439

	try
	{
	$db->setQuery('EXPLAIN ' . ($dbVersion56 ? 'EXTENDED ' : '') . $query);
	$this->explains[$k] = $db->loadAssocList();
	}
	catch (Exception $e)

It would be easy to fix but the problem in QueryMonitor, it does not log a bound params.
https://github.com/joomla-framework/database/blob/4cda5d73eb55ac8a596f261aac08a33d658421fb/src/QueryMonitorInterface.php#L26-L28

So first need to fix QueryMonitor, then can get this issue fixed.

[richard67]

@alikon What do you think? Should this be a release blocker? I think it could be one, but I am not sure.

[richard67]

Related framework issue see joomla-framework/database#214 . Thanks @Fedik .

[Fedik]

I would set it "release blocker", because if we not fix QueryMonitor before the release, later it will be harder to fix because a backward compatibility problems.

[alikon]

yes for me release blocker

[HLeithner]

How can a debug function be a release blocker?

[richard67]

A debug function is something essential for core and extension and whatever else on J4 developers.

Debugging database queries should also be possible when using prepared statements.

[wilsonge]

Agreed

[Fedik]

please test #30580