[sidch]

Yugabyte PM here. Yugabyte SQL query layer is a fork of PostgreSQL 11.2's query layer. This query layer runs on DocDB, a distributed document store whose sharding, replication and ACID transactions architecture is inspired by Google Spanner.

Given that the query layer reuses the native PostgreSQL code, it is wire compatible with the PostgreSQL binary protocol and already supports an extensive set of PostgreSQL language features (including partial indexes, triggers and stored procedures). Most tools from the PostgreSQL ecosystem work without any modification. However, PostgreSQL is an extensive language so claiming 100% coverage is not accurate . For example, GIN and GIST indexes are not yet supported since more work is needed to integrate those language constructs to the underlying distributed storage layer. The more accurate answer would be that YugabyteDB has the best PostgreSQL compatibility in the realm of distributed databases and continues to increase coverage with new releases.