RocksDB

What do you like best?

Log-structured merge tree implementation. Once you've got acquainted with it, you could do really awesome things. And the latency numbers are great. Although RocksDb is not of those that are easy to use, still if you would manage to master it you would gain a reliable, solid instrument not a kind of a swiss knife but rather machete like that would allow you to reach any of your engineering goals.

What do you dislike?

Pure java documentation. Product requires being familiar with some advanced c++ and good understanding of what is hidden under the hood. High entry level. One simply can't use it for 100% 'from the box'. However, I am speaking only about the java programmers.

Recommendations to others considering the product:

Get familiar with code and lst.

What problems are you solving with the product? What benefits have you realized?

Low latency scalable web app in an advertising business with some machine learning implementation. The app actively uses a database. The major requirement is high performance.