PostgreSQL 9.5 Released
iamvego writes: Later than the typical release cadence, PostgreSQL 9.5 has finally been released, and brings with it a slew of new features including UPSERT functionality, row-level security, and some big data features (CUBE/ROLLUP, join pushdown for foreign data wrappers, TABLESAMPLE, BRIN indexing and more). The previous release had brought about some new JSON functions and operators, but they only queried the data; 9.5 comes with new operators which now allow modification of JSON values, so it no longer has to be manipulated outside of the database. PostgreSQL's wiki has a more detailed overview of the new features.
They are and Oracle has been. Now PostgreSQL does too.
After trying it there and learning a bit about it, I don't see why you wouldn't use PostgreSQL
PostgreSQL is better than MySQL in basically every way
"First they came for the slanderers and i said nothing."
slony is the oldest replication option for postgresql but it is also one of the worst.
For a hot standby use the builtin Streaming Binary replication http://www.postgresql.org/docs/current/static/warm-standby.html
For a multi-master setup use BRD http://bdr-project.org/docs/stable/index.html
For a master slave with select queries balancing setup Pgpool-II https://wiki.postgresql.org/wiki/Pgpool-II