Code hot swapping can often trivially be done (by simply compiling and copying the fixed module, then 'l(module)' in the shell) if the module does not change the state record or break function signatures. I have used this countless times to fix a module function with no downtime. You don't always need the full code upgrade procedure, which is indeed far more onerous.
I agree, I should have been more specific. Individual module upgrades are indeed straightforward. That didn't sound like what the poster was describing.
Code hot swapping can often trivially be done (by simply compiling and copying the fixed module, then 'l(module)' in the shell) if the module does not change the state record or break function signatures. I have used this countless times to fix a module function with no downtime. You don't always need the full code upgrade procedure, which is indeed far more onerous.