Managing CachesPhabricator User Documentation (Configuration)
Discusses Phabricator caches and cache management.
Phabricator uses various caches to improve performance, similar to the caches a web browser uses to improve web performance.
In particular, blocks of text which are expensive to render (like formatted text and syntax highlighted code) are often cached after they're rendered for the first time. When they're rendered again, Phabricator can read the cache instead of recomputing the result.
Because text is cached, you may continue to see the old result even after you make certain configuration changes which should affect it. The most common example of this is that if you enable syntax highlighting with Pygments, old diffs and pastes may not appear highlighted.
You may also run into this issue if you modify existing Remarkup rules or develop new ones, or modify other parts of the code that run before the results are cached.
Caches will naturally expire over time, so if they aren't causing a problem you can just ignore the out of date caches and they'll fix themselves eventually (usually within 30 days).
If you don't want to wait, you can purge the caches. This will remove any cached data and force Phabricator to recompute the results.
If you need to purge Phabricator's caches, you can use the CLI tool. Run it with the --help flag to see options:
phabricator/ $ ./bin/cache purge --help
This tool can purge caches in a granular way, but it's normally easiest to just purge all of the caches:
phabricator/ $ ./bin/cache purge --all
You can purge caches safely. The data they contain can always be rebuilt from other data if Phabricator needs it.