Release PostgreSQL 9.4

Major enhancements in PostgreSQL 9.4 include:

Add jsonb, a more capable and efficient data type for storing JSON data

Add new SQL command ALTER SYSTEM for changing postgresql.conf configuration
file entries

Reduce lock strength for some ALTER TABLE commands

Allow materialized views to be refreshed without blocking concurrent reads

Add support for logical decoding of WAL data, to allow database changes to be
streamed out in a customizable format

Allow background worker processes to be dynamically registered, started and
terminated The above items are explained in more detail in the sections below.

URL: http://www.postgresql.org/docs/9.4/static/release-9-4.html