Minecraft 1.9 is a lag-fest. Tick rate slowly drops over time to the point of being unplayable on servers sporting more than 5 players. It's horrible. Minecraft SMP players can't live with this lag indefinitely. It needs fixed in a patch sooner, not later.

Here's a video (made by slicedlime) demonstrating an experiment to reproduce the lag in 1.9 and comparing it to Minecraft 1.8.9:

"How Much Does Minecraft 1.9 Lag, And Why?"

https://www.youtube.com/watch?v=m8hLFol9j5M

This is the still unresolved (reopened) bug report regarding the lag issues:

"Server: Massive Lag in any snapshots post-15w47c"

http://ift.tt/20z7Jl2

I love Mojang and I love the features in 1.9, but this lag is affecting everyone, especially servers. I do not know how to communicate to Mojang that this is an issue that needs fixed. I don't believe Mojang has been deliberately ignoring this, I believe they may just not be aware of it.

New bugs on the bug tracker will simply be marked as duplicate and lead back to the one I posted earlier, so I'm posting here because I know Mojang devs frequent this subreddit.

Edit: Also to add, the lag still exists in 1.9.1 Pre-Release 3