Is it common to have a (near)constantly running 'Deleting stale template caches' task ongoing? I commonly log in to see a task still pending several hours after the last change to the site was made, looking in the database the task usually has 50000+ 'steps'. Each step runs reasonably quickly (although it sometimes hangs) but the process appears to be taking up quite a lot of disk IO according to newrelic and clearly some pages are not getting their cache cleared for quite some time...
What could cause this and it it solvable?
If it's any help I have a reasonably large dynamic menu that i've put in 'cache' tags around and also have one channel with >1200 entries in it and the site is in 5 languages (although the channel with 1200 entries isn't localised) so this isn't a tiny site, performance still seems sluggish at times however.