MVC C# project with a Kentico 12 back-end (no drag-n-drop web parts just using it as back end CMS, with calls to Kentico APIs for data). Basically, we're having a caching issue that only occurs on one of our environments (PROD). I believe this is more of an IIS or environment issue than a Kentico thing. Let me give you some specifics: Kentico 12 MVC v12.0.34 (upgraded from K11) and as stated before we're not using any web parts/components. Kentico is just the back-end CMS, and we use Kentico APIs to pull data for each page and have rolled our own views and models.
We have 2 environments, STG and PROD, both running Win Server 2016 that have a slightly different OS build version STG: v1607 OS build 14393.3115, IIS v10.0.14393.0 PROD: v1607 OS build 14393.2999, IIS v10.0.14393.0
Within Kentico when we update a category, an event is wired for the UPDATE and runs the following code:
CacheHelper.TouchKeys(new[] { "cms.category|all" });
This clears ALL category caching (CacheDependency within Kentico) and when the webpage is refreshed the GetAllCategories method that pulls, you guessed it, ALL categories is called again. If you try it another time, you'll get a cached version until there's a change within Categories (or the cache timing runs out, something like a month). Works exactly as you'd think on the STG box.
Just to see what's going on, I added some Kentico informational logging to check what is happening at different places around this Update event firing. From the EventArgs I can get the source of the event (which category triggered it), and I can see when it's using the cached info and when it retrieves it from the db. Awesome.
The issue that I'm running into is when I run on PROD using the exact same code base, along with the same logging, and trigger the same event, the cache does not get released. The event logging says it has, but when the webpage refreshes, the GetAllCategories is not brand new but the last cached value. The only way to get the new version is to recycle the app pool or shutdown/startup the application within IIS.
There is no Output Caching on the class/methods. Same code base across 2 different servers. Is there some environment variable or IIS setting that could have been set differently on the PROD box?
Any thoughts what could be causing this? Other places to look on the web server? Thanks for your help!
I've had a caching issue similar to this and it turned out that it was down to the Web Farm configuration.
The problem is that when you have the CMS and MVC both hosted on the same server Kentico cannot tell them apart in Web Farms.
Make sure that your CMSApp and MVC projects each have web.config keys to set the CMSInstanceNameSuffix key. This will help differentiate them in Web Farms and allow web farm tasks to be correctly generated for your MVC app.