* Force the default wal_sync_method to be fdatasync on Linux
* Fix "too many KnownAssignedXids" error during Hot Standby replay
* Fix race condition in lock acquisition during Hot Standby
* Avoid unnecessary conflicts during Hot Standby
* Fix assorted bugs in WAL replay logic for GIN indexes
* Fix recovery from base backup when the starting checkpoint WAL
record is not in the same WAL segment as its redo point
* Fix corner-case bug when streaming replication is enabled
immediately after creating the master database cluster
* Fix persistent slowdown of autovacuum workers when multiple workers
remain active for a long time
* Fix long-term memory leak in autovacuum launcher
* Avoid failure when trying to report an impending transaction
wraparound condition from outside a transaction
* Add support for detecting register-stack overrun on IA64
* Add a check for stack overflow in copyObject()
* Fix detection of page splits in temporary GiST indexes
* Fix error checking during early connection processing
* Improve efficiency of window functions
* Avoid memory leakage while "ANALYZE"'ing complex index expressions
* Ensure an index that uses a whole-row Var still depends on its table
* Add missing support in "DROP OWNED BY" for removing foreign data
wrapper/server privileges belonging to a user
* Do not "inline" a SQL function with multiple OUT parameters
* Fix crash when inline-ing a set-returning function whose argument
list contains a reference to an inline-able user function
* Behave correctly if ORDER BY, LIMIT, FOR UPDATE, or WITH is
attached to the VALUES part of INSERT ... VALUES
* Make the OFF keyword unreserved
This prevents problems with using off as a variable name in
PL/pgSQL. That worked before 9.0, but was now broken because
PL/pgSQL now treats all core reserved words as reserved.
* Fix constant-folding of COALESCE() expressions
pg_upgrade (formerly called pg_migrator) allows data stored
in PostgreSQL data files to be migrated to a later PostgreSQL
major version without the data dump/reload typically required
for major version upgrades, e.g. from 8.4.7 to the current
major release of PostgreSQL. It is not required for minor
version upgrades, e.g. from 9.0.1 to 9.0.4.
