While Swift is generating cache, the CPU usage can be higher than usual as Swift Performance is using more aggressive optimization techniques than any other plugin on the market. When your site is hosted on a limited server and you have hundreds or even thousands of pages, prebuild can take a while. When you set Cache Expiry Mode on Time Based Mode with a short Expiry Time then Swift is constantly busy (pre)building al known pages, posts, products, categories, tags, etc etc.. This may even result in getting 500 errors.
To avoid this, a good and fast solution is to set Cache Expiry Mode on Action Base Mode and/or Cache pages on first visit, so second visitor get served cached pages. This is how most cache plugins work. To achieve this you need to disable Prebuild Cache Automatically in Settings->Caching->Warmup and enable Optimize in Background in Settings->Optimization->General (disable Optimize Prebuild Only).
It is also good practice to clean your warmup table once:
Best practice to keep warmup table clean and efficient:
- Disable Cache 404 pages in Settings->Caching->General.
- Exclude Post Types in Settings->Caching->Exceptions there is also a custom post type, called Oembed cache. This one you need always to exclude, but probably you can exclude most,except posts, pages and products.
- Some themes/plugins create dynamical Scripts, so make sure you disable Cache 404 pages in Settings->Caching->General and Discover New Pages in Settings->Caching->Warmup.
- Reset Warmup Table once.
If you still notice some unwanted URLs and/or Pages in your wamup table, you may exclude those in Settings->Caching->Exceptions: Exclude Pages and in Settings->Caching->Exceptions: Exclude URLs.
In future version of Swift we include also some improvements regarding to _autosave and revision posts/pages, which for now can be excluded in Settings->Caching->Exceptions: Exclude URLs with /revision and /autosave.
If your sitemaps geting cached and you don`t want those URLs getting cached by Swift, you can exclude them simply with .xml in
in Settings->Caching->Exceptions: Exclude URLs.
When you don´t need category and tags URLs being cached, disable Prebuild Terms in Settings->Caching->Warmup.