[4.0] Improve menu item list performance on multilingual sites

[SharkyKZ]

Summary of Changes

Replaces JOIN and GROUP clauses in query with a subquery for improved performance.

Testing Instructions

Set up a multilingual site.
Enable language associations.
Create some menu items with and without associations
View menu item list in backend.

Expected result

Works like before.

Documentation Changes Required

No.

[richard67]

I have tested this item ✅ successfully on 426111e

Tested with MySQL 5.7 and PostgreSQL 10.10.

About performance I can't say anything because my test data set is too small.

But I can confirm everything works as well as before, carefully watching PHP error log with PHP error reporting set to maximum and watching database log.

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[alikon]

I have tested this item ✅ successfully on 426111e

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[alikon]

RTC

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[wilsonge]

Thanks!

[Stuartemk]

Tested and implemented in joomla 3.9.12, php 7.2, Mysql 5.7
Tested on Articles list, Newsfeeds list, Contact list, Menu list.
NOT tested on articles filtered by Tags, due to my little knowledge to implement it in Joomla 3.9.12

Everything works as usual, I have not encountered problems, the performance has improved a bit, unfortunately I do not have the necessary knowledge to measure the percentage of improvement.

However, the Menu Component continues to perform poorly since this improvement would only improve performance in the multilanguage area, but individually the Menu Component continues to create a TTFB in sites with several menus.

I make available a site with real load for case study in case anyone is interested in finding the definitive solution to the poor performance of the Menu Component in Joomla, which from my personal point of view, is the only thing that limits joomla to be The best CMS.

Thank you all for your great work!

[infograf768]

@Stuartemk

Tested and implemented in joomla 3.9.12

This PR was for 4.0