I'm also experiencing performance issues issues with 1.13.1 on the server side. I have a small Linode hosted server and the upgrade from 1.13 to 1.13.1 made a big impact. We have a spawn area that seems to be the culprit. There is a lot of redstone, water mechanics, and villagers in the spawn area, but it did not seem to be nearly as much of an issue in 1.13. I've also run similar stuff before 1.13 and never had issues unless there were many people on the server. I've upgraded the server now and will report if it is still an issue. Was previously running on the 4G 2CPU Linode config with no issues until 1.13.1.
I'm also experiencing performance issues issues with 1.13.1 on the server side. I have a small Linode hosted server and the upgrade from 1.13 to 1.13.1 made a big impact. We have a spawn area that seems to be the culprit. There is a lot of redstone, water mechanics, and villagers in the spawn area, but it did not seem to be nearly as much of an issue in 1.13. I've also run similar stuff before 1.13 and never had issues unless there were many people on the server. I've upgraded the server now and will report if it is still an issue. Was previously running on the 4G 2CPU Linode config with no issues until 1.13.1.