A critical fix repairs an error in ReadBuffer that can cause data loss
due to overwriting recently-added pages. This applies to the 8.1 and
8.0 branches on all platforms.
Note that this update might require a reindex of textual columns under
certain conditions; please see UPDATING.
Other fixes included are:
-- Character string locale comparison bug. This may require a REINDEX
on text column indexes in some locales, such as Hungarian.
-- Prevent accidental changes of locale by plperl
-- Two fixes for Japanese encodings
-- Two fixes for COPY CSV
-- Fixes for functions returning RECORD
-- Fixes to autovacuum, dblink and pgcrypto
The new release includes performance improvements and advanced SQL
features which will support bigger data warehouses, higher-volume
transaction processing, and more complex distributed enterprise
software.
Major new features in this release include:
Roles:
PostgreSQL now supports database roles, which simplify the
management of large numbers of users with complex
overlapping database rights.
IN/OUT Parameters:
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.
Bitmap Scan:
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.
Table Partitioning:
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.
For a more complete listing of changes in this release, please see the
Release Notes visible at:
http://www.postgresql.org/docs/current/static/release.html#RELEASE-8-1
