Question How to handle large forum with many categories/sub-categories

I am trying to understand how kunena software use the "permissions" in terms of load time, and overall. In regards to what forums can be seen vs what can not be seen.

Lets say you have a large forum, that is setup more like a directory. With many categories and sub catagories. I'm talking like 1500 or more sub cat in more then 100 or so forums. When a user access that forum it has to check all the forums, sub forums etc to see if it is allowed to be visible or what not. which takes a long time if you have a lot of forums and even longer if you have a lot of users.

Now what happens if you have all the forums, sub forums etc on one page but it is not visible to the users. Then you have different menu links that pull up a section of the forum. Would it only need to check the permissions of that section or would it still run threw the whole list as well?

An Example:
You have a automotive forum that talks about every model and type. Each type has 10 or so sub catagories. ( like a directory) If you have a custom home page with links or a search type thing could you have it only pull up that section in the forum with just those ten or so links and not have to check every forum for permission access? Would this help with load times?

I know there is joomla extensions that can make directories, and I do plan on converting over to something but for the mean time this is the fastest and easiest way to achieve what I am after. However I need to make sure my site will not crash or page times be too slow.

This is a very interesting question. There are several ways that you can tackle the issue.

One way is to segment your forum so that you have different menu items that handle those areas of particular interest to your users.

As an example, this forum here at www.kunena.org has a "playground" aread. You will see a link to this area on the main menu at the top of the page. The playground forum is simply a category with its own menu (although the menu items mirror the same options used in the "main" forum. Here's another example of the same thing ( www.getransportation.com ).

Of course, using a component like Artof User, you can assign different permissions to each user so that they can access certain parts of your forum (e.g. categories and sub-categories), if this idea appeals to you. In terms of what load this places on your website, I cannot give you any specific metrics but, obviously, the larger the forum and the more traffic you receive, it helps to have the best possible platform for operating it. Under these conditions it probably pays to do your research and evaluate different webhosting solutions to achieve "best fit" for your needs. Usually, but not always, the more you pay the better is the solution.

This does not actually address the questions that you've asked but I hope I've given you a few things to consider.

With a large forum like this one at www.kunena.org , we've tried to minimise the number of categories so that people will find what they're looking for in the shortest amount of time. Even with the limited number of categories used here, people often misplace their messages - which means that important questions may be overlooked or remain unanswered. There's a trade-off in terms of usability and forum moderation depending on how many categories you have and your eagerness to organise question-and-answer issues in the most efficient and effective way.

FYI

Kunena checks permissions once per visit and uses a cached result for all further page views. Only if permissions are changed or the user permissions cache is cleared do we recalculate them.

Kunena checks permissions once per visit and uses a cached result for all further page views.

If the actual forum is not visible, and the menu link is just to a category with 10 or so subforums. Will it just check that one category and its ten subforums or the whole forum in general.

When user logs in Kunena generates a list of allowed category ids and saves those into database. So read permissions are checked only once for a while.

There are some differences on how Kunena 1.6 and 2.0 does this: K1.6 makes the check every x minutes/hours (session timeout), but for K2.0 it's once per session. So when you log out or session times out, permissions are forgotten -- which is usually a good thing if user/category permissions change (it's easy to ask user to logout/login). If the user changes permissions himself, category access should be recalculated right away.

For other permissions, some checks are performed every time (moderation, administration rights) to make sure that the user really has access to all the administrative tasks.

Main difference between Kunena 1.6 and upcoming Kunena 2.0 is that later has been optimized for speed in all levels: database schema scales up without noticeable performance loss, code has been profiled and optimized for speed and caching is used intensively (making sure that data is fresh).. Kunena 2.0 is running in 2M post forum with 24 sections and ~300 categories and it is fast. And 300 categories is a lot -- they cover everything from politics to sex.

Having 1500 categories is way too much -- not even the largest forums have that number of categories, mostly because of people cannot handle that number. Another reason is that most of those categories will be empty anyway or they just have handful of topics, making it very hard to find interesting discussions.

Believe me; a few months ago we decided to split my own little (200k posts) pet forum to have categories and subcategories for every species and main topics (general, health, food etc).. We only did it for one smaller main topic and even then we had so much opposition that we had to revert the change. It was also obvious why people didn't like it -- instead of looking into one category, you had to visit 5 or more just to find out the interesting discussions.

I have not dropped the idea of having better categorized topics, so I've been playing with some new features that makes it possible.

Im bringing these post back to life. The reason why I would want so many sub forums etc is because it is going to be like a directory. I will have a forum setup for various cities, and then different sub forums like things to do, local specials, local business etc. So users will be logging in going to "there" city to find out what is going on.

So I thought by creating menu links that goes right to their city would only load 10 or so sub forums and cause less strain since it does not need to check the whole forum.

Is this the best way to attack this? Will kunena be able to handle lets say 500 cities across the U.S. with maybe 10 or so sub forums?