In the world of PostgreSQL compatible databases, a newcomer is YugabyteDB. Same protocol, similar opensource license, reusing postgres query layer but on a distributed storage plugged in place of heap tables and btree indexes. We will explain the reason for it, why it cannot be just an extension, and why it reuses PostgreSQL. Similarities and differences, with an overview on the underlying technology: LSM Trees, distributed storage, logical clock, consensus protocols.

The goal is to answer the questions like: why another database instead of an extension? when can it can substitute to standard PostgreSQL, and why? when it is not a good choice and PostgreSQL is the best fit? what is distributed vs. sharding when it comes to scaleout?