Does MODX automatically clear caches across all contexts when a system setting is changed?

Direct Answer

No. MODX Revolution does not automatically clear caches for every context when a system setting is saved. Only the global/system cache partition (typically core/cache/default/) is refreshed. Each context’s cache partition (core/cache/<context_key>/) remains stale until explicitly cleared.

There is no core event—OnSystemSettingSave, OnSiteRefresh, or OnCacheClear—that flushes all context caches. OnSiteRefresh clears only the current context’s cache.

Why This Is the Design

System settings are global; context settings override them per-context. MODX treats context caches as independent, so a global setting change does not assume every context needs invalidation. This avoids unnecessary cache rebuilds on high-traffic sites.

Recommended Practices

Manual (ad-hoc)

1. In the Manager, after saving a system setting, click the Clear Cache button (top menu). This flushes all context partitions.

Programmatic (single call)

$modx->cacheManager->refresh(); // clears every registered context partition

Automated (plugin on OnSystemSettingSave)

$contexts = array_keys($modx->getContexts());
$modx->cacheManager->refresh(['contexts' => $contexts]);

Place this in a plugin tied to OnSystemSettingSave if you want every system setting change to refresh all contexts automatically. Be aware this can cause performance spikes on busy sites; consider targeted clearing or a scheduled refresh instead.

Exception: Context Settings

When a context setting (not a system setting) is saved via the Manager, MODX automatically clears that specific context’s cache only.

Verification Steps

1. Change a system setting (e.g., site_name) in the Manager.
2. Check timestamps on core/cache/default/config.cache.php and core/cache/<your_context>/config.cache.php.
3. Only the default partition updates; context partitions stay unchanged until you run a full cache clear.

Version Note

This behavior is consistent across MODX Revolution 2.x and 3.x. Custom cache handlers (Redis, Memcached) follow the same partition logic unless they implement cross-context invalidation themselves.

Diagnostic detail that would change the recommendation: Are you using a third-party cache handler or extra that claims to synchronize caches across contexts? If yes, consult its documentation—some extras alter the default invalidation scope.