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Understanding siteCache.idx.php and Evolution CMS Cache Internals
A deeper historical look at how the Evo cache index works and why it could become a performance bottleneck.
This article goes beyond ordinary “clear the cache” advice and looks directly at the old Evolution cache structure. Its focus is the assets/cache/siteCache.idx.php file, which stored not only page cache references, but a wide range of runtime data such as config values, alias listings, document maps, snippet references, and more.
The key historical insight is that the cache index was doing a lot of work. As projects grew, that central file could become large and expensive, which made cache behavior itself part of performance tuning.
What the article breaks down
- how config data lands in
$modx->config - how alias maps and document listings are cached
- how the document tree and mime-type information are stored
- why central cache files can become a hidden scaling problem
Why this still matters
It captures the engineering mindset around old Evo performance work: understanding internal cache structures was often more valuable than applying random “speed tweaks.” For a historical archive, that is exactly the kind of technical depth worth preserving.
Related posts
Caching Dynamic Snippets in Evolution CMS Without Losing Dynamic Output
Deeper caching guidance from the older Evo layer
Keeping Jot Placeholders Working on Cached Pages
A historical workaround for keeping Jot output alive even when the page itself remains cached.