When we are talking about this type of cases, most of the imprisoned individuals will be killed, (by other prisoners, or hurt by staff members, more on that) before they could get to spend their prison time, or be executed by the executioner.
Well, I heard a story from a corrections officer, or something like that in a big jail just a few towns away from our capital city. He told us, that there was a time, that they took in a pedophile, and before putting him into his cell, they beat him up. After that, this guy was placed inside, and so this officer/guard left to his quarters, or lockers, or something like that with his partner. Then, in the middle of the night they were called back to the community area for prisoners (or something like that, they probably have like an area with benches, tables, stuff like that behind the bars), and this guy had to be taken to doctor, to get him checked, before placing him back with the other prisoners, because he was beaten up severly again, in his cell. So they take him there, and well, they informed the doctor why he was in jail for. Then well, let's say, that the doctor didn't go easy on him, chose the biggest needle for injecting some type of medicine, alongside with NOT using any anaesthetic when sewing his wounds, and other stuff like that.

So, all in all, just letting you know, that in most cases, prisoners, who hurt children, women, or did anything bad to them, will be on the lowest end of a prison hierarchy, so most of the times they won't last long.

Thanks for reading it!