Designed, built and tested by a large and thriving community and backed by a growing number of corporate sponsors and support companies, version 8.1 will expand the scope of PostgreSQL application development.
The new release includes performance improvements and advanced SQL features which will support larger data warehouses, higher-volume transaction processing and more complex distributed enterprise software.
New features in this release include:
PostgreSQL now supports database roles, which simplify the management of large numbers of users with complex overlapping database rights.
PostgreSQL functions now support IN, OUT and INOUT parameters, which substantially improves support of complex business logic for J2EE and .NET applications.
Two-Phase Commit (2PC):
Long in demand for WAN applications and heterogeneous data centers using PostgreSQL, this feature allows ACID-compliant transactions across widely separated servers.
Some Performance Enhancements found in this release include:
Improved Multiprocessor (SMP) Performance:
The buffer manager for 8.1 has been enhanced to scale almost linearly with the number of processors, leading to significant performance gains on 8-way, 16-way, dual-core, and multi-core CPU servers.
Indexes will be dynamically converted to bitmaps in memory when appropriate, giving up to twenty times faster index performance on complex queries against very large tables.
The query planner is now able to avoid scanning whole sections of a large table using a technique known as Constraint Exclusion.
Shared Row Locking:
PostgreSQL's "better than row-level locking" now supports even higher levels of concurrency through the addition of shared row locks for foreign keys.
PostgreSQL 8.1.0 can be downloaded from the following locations:
Other Binaries, including Linux, Mac OSx and Solaris
Installation guideline for PostgreSQL Mac OS X version :