Image Transforms and Cache Clear Often Crash a Server

[matthewstick]

We are kind of scared of the "Clear Caches - All" - but really these three:
Asset caches
Asset indexing data
Asset transform index

We have some setups where we clear and it can bring the site down. We've probably launched about 50 craft sites over the years. And it's just something we shy away from through experience. I think it's mostly on sites that have tons of images and tons of images on a particular page.

Would love for the image transforms to be throttled more slowly. Perhaps too many of them run at once and kill our server? Maybe add a new config setting called: maxImageTransformThrereads = 20 (default), but we can override the default? I just made up that 20 now. I don't know what your default it. If it was more sequential perhaps it won't kill the server? I'm just guessing. Somehow I doubt it's one image transform thread that can kill a server. Often these are fairly strong aws ec2 instances.

Not sure the best way to check this or test this. But I think there's room for improvement.