Security Fixes
* CVE-2015-0241 Buffer overruns in "to_char" functions.
* CVE-2015-0242 Buffer overrun in replacement printf family of functions.
* CVE-2015-0243 Memory errors in functions in the pgcrypto extension.
* CVE-2015-0244 An error in extended protocol message reading.
* CVE-2014-8161 Constraint violation errors can cause display of values in columns which the user would not normally have rights to see.
JSON and JSONB Unicode Escapes
Other Fixes and Improvements
* Cope with the non-ASCII Norwegian Windows locale name.
* Avoid data corruption when databases are moved to new tablespaces and back again.
* Ensure that UNLOGGED tables are correctly copied during ALTER DATABASE operations.
* Avoid deadlocks when locking recently modified rows.
* Fix two SELECT FOR UPDATE query issues.
* Prevent false negative for shortest-first regular expression matches.
* Fix false positives and negatives in tsquery contains operator.
* Fix namespace handling in xpath().
* Prevent row-producing functions from creating empty column names.
* Make autovacuum use per-table cost_limit and cost_delay settings.
* When autovacuum=off, limit autovacuum work to wraparound prevention only.
* Multiple fixes for logical decoding in 9.4.
* Fix transient errors on hot standby queries due to page replacement.
* Prevent duplicate WAL file archiving at end of recovery or standby promotion.
* Prevent deadlock in parallel restore of schema-only dump.
* Add materialized views
* Make simple views auto-updatable
* Add many features for the JSON data type, including operators and functions to extract elements from JSON values
* Implement SQL-standard LATERAL option for FROM-clause subqueries and function calls
* Allow foreign data wrappers to support writes (inserts/updates/deletes) on foreign tables
* Add a Postgres foreign data wrapper to allow access to other Postgres servers
* Add support for event triggers
* Add optional ability to checksum data pages and report corruption
* Prevent non-key-field row updates from blocking foreign key checks
* Greatly reduce System V shared memory requirements
