* Query language enhancements including "INSERT/UPDATE/DELETE
RETURNING", multirow VALUES lists, and optional target-table alias
in "UPDATE"/"DELETE"
* Index creation without blocking concurrent
"INSERT"/"UPDATE"/"DELETE" operations
* Many query optimization improvements, including support for
reordering outer joins
* Improved sorting performance with lower memory usage
* More efficient locking with better concurrency
* More efficient vacuuming
* Easier administration of warm standby servers
* New FILLFACTOR support for tables and indexes
* Monitoring, logging, and performance tuning additions
* More control over creating and dropping objects
* Table inheritance relationships can be defined for and removed from
pre-existing tables
* "COPY TO" can copy the output of an arbitrary "SELECT" statement
* Array improvements, including nulls in arrays
* Aggregate-function improvements, including multiple-input
aggregates and SQL:2003 statistical functions
* Many "contrib/" improvements
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