From Joomla! Documentation
Article stub for purge expired cache.
How to Access
Select Tools → Purge Expired Cache from the drop-down menu on the Back-end of your Joomla! installation.
This tool will purge all expired cache files from the cache folders. Cache files which are still current are not purged.
- Because this process has to check each cache file individually, it is slower and requires more system resources than the Clean Cache option. However, once the purge process is complete, there should be no loss in speed for users of the site, because all current cache files are still available. In contrast, the Clean Cache option runs more quickly, since it just deletes all of the files in each cache folder. However, the website may be a little slower immediately after running Clean Cache, since in that case all cache files -- including current ones -- are removed, so users lose the benefit of using the cache files until they are re-created.
- If you have a large number of cache files and your server setting for 'max_input_time' is set to less then 60 seconds, you may receive a PHP warning message saying that the process exceeded the maximum time allowed. In this case, no harm is done but all of the files may not have been purged. It is ok simply to re-run the process.
At the top right you will see the toolbar:
- Purge Expired.Click on this Button will start the purging process.
- Help. Opens this Help Screen.
- Purging of cache files is recommended to be run on a regular basis. Use either this option or the Clean Cache option.
- If you receive a PHP timeout error or warning during the process, it is ok to start this program again.