Performance and page cache

IllusionCMS keeps fully rendered pages in memory and serves them directly – typically in under a millisecond instead of several tens of milliseconds.

• Automatically up to date: Every change in the CMS (pages, Snippets, CSS/JS, Collections, files, imports) clears the cache. The live preview while typing doesn’t clear it.
• REST data: Pages with REST sources stay in the cache at most as long as the source’s cache duration.
• Change of day: At midnight the cache expires, so that lists with today (upcoming events only) are correct the next day.
• Not cached are pages with Disable cache, previews and error/404 pages.
• You only need Disable cache if a page should look different on every request without anything changing in the CMS – for example with {% now "15:04" %} or a random selection.
• Browser: Pages carry an ETag; the browser doesn’t reload unchanged pages. The transfer is gzip-compressed.

Under Settings → System you see the number, size and hit rate and can clear the cache manually. You set the size at startup (-cache-mb, default 128 MB).