Drupal cache tables are empty, not receiving data

my drupal cache tables are always empty. Cron is running ok. How is it possible? What can I do, so they are receiving da开发者_开发百科ta? Thanks

Go to Site configuration -> Performance -> Caching mode: Normal

You only want to turn on caching for production. If you are a developer and you want to test things, make sure caching is turned off.

Running Cron will actually clear the cache tables. So if you have cron set up to run at a high frequency (every few hours) you're cache tables will get empty as well. Keep in mind that system_cron() calls cache_clear_all().

So make sure:

• caching mod: Normal
• cron is runngin every day (should be adequate for most sites)

But Drupal also caches some other things like:

• CSS files (useful for IE which only loads the first 31 stylesheets, while a Drupal site will definitely have more than that)
• JavaScript files - never used it, not even in production, but it should make sense for a high traffic web-site