Why did a site on Symfony 2 start working very slowly after clearing the cache?

Question

symfony

The Symphony site after I cleared the cache started to work very slowly (the page loads about 30-50 seconds). Before that it worked fine.
I cleared the cache with the command:

php app/console cache:clear --env=prod --no-debug --no-warmup

Perhaps something else is needed to overclock this cache?
And in general, what commands are needed to update the code, images, styles and js?
New to Symfony.

Answer 1

What do you think the --no-warmup parameter is responsible for?