It is again time to write something about the things I do with Dotnetnuke. What I write may be wrong so if you see something that is not correct please correct me...

After adding Text/HTML to your site on many tabs you may want to update the cache settings (default for Text/HTML is 1200 seconds) for those module instances. You can do that manually by going into the module settings of that module but if you have a lot of Tex/HTML instances you may want to use an SQL statement for that:

Before we can do anything we need to find out what the ModuleDefId is for Text/HTML. The ModuleDefId for Text/HTML is stored in the ModuleDefinitions table. In my case the ModuleDefId for Text/HTML is 102. Now that we know that we run a query to find out on what tabs a Text/HTML instance is installed:

select * from tabmodules
inner join Modules on TabModules.ModuleId = Modules.ModuleId
where moduledefid = '102'

A list is shown with tabs that contain an Text/HTML instance. For performance increase we want to set the CacheTime for all those Text/HTML instances to 1 day = 86400 seconds.

update tabmodules
set TabModules.CacheTime = '86400'
from TabModules inner join Modules on Modules.ModuleId = TabModules.ModuleId
where ModuleDefId = '102'

Next time you run the first query you will see that the CacheTime column has been updated with '86400'. All you need to do is restart the application because settings in the TabModules table are cached or you can flush the cache in the Host Settings.

Increasing the CacheTime setting for modules can improve performance of your site, especially for Text/HTML because in many cases that is static content that does not change a lot.

There is one other settings that is important for caching Modules. In the Host Settings (DNN 4.4.0) check under Performance the 'Module Caching Method'. If it is set to memory it will be handled in memory and the Workerprocess on IIS will consume more memory on your server. If your hosting company has set a limit on the amount of memory you are allowed to use you may want to set the Module Caching Method to 'disk'.

CacheTime is the amount of time information from a module stays in the cache. If the information from a module like the Text/HTML module is retrieved from the cache response is most of the time a bit faster compared to when it is retrieved from the database in the case where CacheTime is set to '0' or the the CacheTime is expired. Setting a CacheTime for a Module reduces the number of calls to the database.

An example: If I set CacheTime to 86400 = 1 day for the Text/HTML module from the time it is called for the first it takes 1 day before another call to the database is made. Less calls to the database increases in most cases performance. This works very well for static content. In the case of a module that contains for example a query to a table in your database (Report Module) it is generally not a good idea to set CacheTime to a larger value then '0'. If you set a CacheTime larger than '0' for such a Module outdated information will be shown to the user.

Did this help?

Mariette,

One additionnal question. The cache is on the server where I am hosted, or on each computer from where people access my website ??

DV FX