HTML rendering cache performance logs

Question

Recently, our Prod environment caused downtime due to some caching issue as reported by the agency that hosts our application. Sitecore support asked us to enable HTML Rendering Cache on select renderings (Header, footer, and navigation) because these are common in our pages. We enabled these in our staging environment by ticking Cacheable and Vary By Data checkbox in Cache Section of rendering item.

Now, is there any way for us to see in logs or somewhere in Sitecore that enabling HTML cache rendering did something for performance? Because we want to see significant, positive results before doing this on our prod environment

Answer 1

This is a big topic with many blog posts and presentations on it.

• Have you already used the cache.aspx and stats.aspx to see what happens? You can find these in the Admin section of the Control Panel. These should be run from the same instance of Sitecore configured as a Standalone instance (often the local dev environment).
• It's an iterative kind of thing. You make a change and test. Rinse and repeat.
• When on the stats.aspx page: the basic process is to clear stats, clear cache, refresh page. See what appears. You can see in the stats which component results in the highest number of item queries. The statistics are in memory on the running instance in IIS.
• When you identify a component to focus on, you change the cache setting and then clear stats, clear cache refresh page, see what happens.
• Example: Navigation is exactly the same on every page. You don't have it cached. Every page you go to takes 1 second to load. Enable the cache on the page using whatever vary by settings. Then you start testing and the page takes 1 second the first time. 500 ms every other time.
• Research the Vary-By settings. Those settings determine the cache key used to store in memory. The more boxes you check the longer/more unique the key. Goal is to cache as many components as possible using settings that allow it to work across the site. You could choose the wrong settings and cause the component to cache once and appear everywhere when you expect it to be unique per page or cause it to cache once per page when you need it once for the entire site.

Resources

• Official docs - Configuring Caching
• Tuning and Monitoring Sitecore Cache