The function used to clear the cache, is used in this solution. That same function is called from a few other places in core and is also called by various 3rdparty modules. The cacheform table is also not cleared by the core cache clearing methods; see function In order to manage the size of cacheform on high traffic sites, please see the Safe cacheform Clear contrib module.
When cron is run on Drupal, all caches are cleared and rebuilt without the need for a human to manually do it. If this question pertains to theming, you should disable the caching mechanisms (cssjs aggregation) and you won't have to clear the cache data when you make changes.
Simple Query to Delete All Drupal 7 Cache Tables Manually. April 22, 2014 Sometimes the only way to regain access to your drupal site is to remove information from the cache tables manually. Prior to D8 to clear cache manually one could truncate all tables beginning with cache.
In Drupal 8 there are still tables starting with cache, but there's also a cachetags table. Is the advice in D8 still to truncate cache if you need to clear cache manually?
Script and instructions to manually or automatically clean the Drupal 8. x cache tables (cacheconfig, cachecontainer, cachedata, cachedefault, cachediscovery, cacheentity, cachemenu, cacherender and cachetoolbar). Truncate cacherelated database tables.
Another method of clearing the cache is to truncateor clear all the data fromthe cacherelated database tables. These are all the tables that begin with" cache" (after the sitespecific table prefix, if there is one).