We are in the process of evaluating CockroachDB vs Rethink internally and we've found CockroachDB to perform very poorly without obvious disk or CPU issues. I'm curious if you've seen different especially as it relates to Rethink.

I didn't do comparisons. But RethinkDB has straightforward issues like a slow QL implementation using a lot of CPU and a lot of disk space usage. Change feeds have a few scaling issues if you want a lot of them. I don't know that it has mysterious kinds of excessive resource usage. I'm a dev of RethinkDB, not an end user, so I might be seeing the worst side of it. I haven't used Cockroach or TiDB.

TiDB seems to have a pretty active community, judging by its repo (https://github.com/pingcap/tidb). Also, saw this thread on TiDB v MySQL recently that's pretty detailed (https://www.quora.com/How-does-TiDB-compare-with-MySQL). Looks like a good option worth trying out.

Can you clarify on those problems?

Performance, mostly. Too much CPU and disk usage. Change feeds don't scale well.

What problems (outside I guess the current status of the project as a whole)?