[J5] All articles data is loaded in Category Menu when 0 articles are set to be displayed - performance impact

[AndySDH]

POST UPDATED TO JOOMLA 5

Steps to reproduce the issue

• Have a category with many articles (hundreds? the more the better to see the performance impact. for this example I'll use a random number of 432 articles)
• Create a Category Blog Menu Item of that category, but in "Blog Layout" options set 0 articles to display in all four inputs.
• Visit this menu item in the frontend.

Expected result

I would expect the page to load super fast because there is no article data to load whatsoever.

Actual result

The loading is VERY SLOW, taking dozens of seconds, if not minutes, depending on the amount of articles and content within those articles. Why? Because Joomla is loading in the background the data from ALL those 432 articles as if they were all displayed at the same time in that one page with no pagination, despite the fact you're actually displaying 0!

Additional comments

Still happening as of Joomla 5

Additional comments

To top it off, obviously, if in the options you put to only display "1" article, of course it loads super fast because it only loads 1 article, correctly. You put "20" articles? It displays quite fast because it only loads 20 articles, correctly. You put "0" articles? It loads incredibly slow because it loads all 432 articles in the background (and then showing 0 at the end of the loading). This can't be intended behavior.

In an old comment, someone suggested to put "-1" instead of "0" articles in the Menu options to work around the problem, and while it worked before, now in Joomla 5 it's no longer possible because it's impossible to save a menu item with a "-1" as the value. So now there is not even a workaround anymore.

PS: You may ask, why would you want to input 0 articles in the first place? Well, it could be useful for cases when you might want to only display the description of the category, or if you want to display the articles via other means (content plugins or modules) and you don't want to display them natively. Plus, the use case shouldn't even matter, it's just a wrong/flawed behavior regardless.

[csthomas]

Because $limit = 0 usual means no limit there is hard to change it in J3.x.

It can help only in the blog:

diff --git a/components/com_content/models/category.php b/components/com_content/models/category.php
index 50c66d0efa..a4f4128daa 100644
--- a/components/com_content/models/category.php
+++ b/components/com_content/models/category.php
@@ -190,6 +190,13 @@ class ContentModelCategory extends JModelList
                if (($app->input->get('layout') === 'blog') || $params->get('layout_type') === 'blog')
                {
                        $limit = $params->get('num_leading_articles') + $params->get('num_intro_articles') + $params->get('num_links');
+
+                       if ($limit === 0)
+                       {
+                               // We want 0 articles but 0 means no limit
+                               $limit = -1;
+                       }
+
                        $this->setState('list.links', $params->get('num_links'));
                }
                else

[ggppdk]

@csthomas

So you are saying that limit zero for DB model

• means 'retrieve all'

but then

• some com_content layouts will show zero items (blog layout)
• and all other layots will show all of them

Since the category DB model already has special handling for blog layout as you are showing above
I think your fix suggestion is valid

[csthomas]

If this is OK then I will make PR when I have more time.

[AndySDH]

That sounds like a good fix, simple and effective :)

[csthomas]

The fix is not complete because there is a second query SELECT COUNT(*)..., which still is executed.

[jwaisner]

@AndySDH Can you confirm this issue still exists in J3?

[AndySDH]

Yup still an issue

[rdeutz]

Closing this because it is expected behaviour.

To be a bit more specific: A value of 0 means no limit. A Category Blog Menu Item is for displaying articles of a category. If you want to show only the category description you can create a special view by copy the view to your template and remove the showing of articles.

[AndySDH]

@rdeutz Sorry but that's stupid. If 0 meant no limit, then entering 0 would show all articles. But it doesn't.

Instead, entering 0 shows 0 articles. While still loading all their data in the background as if it was showing all.

It should be either one way (show 0 articles, load 0 data), or the other (show & load all articles)

Currently it's inconsistent and a mess

[trananhmanh89]

#32612 new way to get this issue.

It happends on my site. I'm using com_content to store articles, but doesn't use it to display. If someone know this issue, he can easily break my site. So i have to block access to com_content.

So annoying.

[rdeutz]

For me it is a missuse of the Category Blog for something that it is not made for. But I am open to look at a PR so that we can check what the side effects are.