> Actually, change this to I *need* to edit it. There's several errors.
> Working on it now, but can't promise to finish by tommorrow AM.
Done, actually. Apologies for tab spacing; I can't seem to get this to
work right in emacs-sgml. So I've attached the file instead of a patch.
I edited several feature descriptions, re-assigned several to
appropriate categories, rearranged new features so that they are listed
in more-or-less order of importance, and elimitated two new sections
which were redundant with existing sections.
Please check for further errors.
--Josh Berkus
Title: Release 8.5alpha2
Overview
PostgreSQL alpha releases are snapshots of development code. They
are intended to preview and test upcoming features and to provide
the possibility for early feedback. They should not be used in
production installations or active development projects. While the
PostgreSQL code is continuously subject to a number of automated
and manual tests, alpha releases might have serious bugs. Also
features may be changed incompatibly or removed at any time during
the development cycle.
The development cycle of a PostgreSQL major release alternates
between periods of development and periods of integration work,
called commit fests, normally one month each. Alpha releases are
planned to be produced at the end of every commit fest, thus every
two months. Since the first commit fest starts within a month from
the beginning of development altogether, early alpha releases are
not indicative of the likely feature set of the final release.
The release notes below highlight user visible changes and new
features. There are normally numerous bug fixes and performance
improvements in every new snapshot of PostgreSQL, and it would be
too bulky to attempt to list them all. Note that many bug fixes are
also backported to stable releases of PostgreSQL, and you should be
using those if you are looking for bug-fix-only upgrades for your
current installations.
The release notes are cumulative over all alpha releases. Items
that are new in the latest alpha release
are emphasized.
Migration
To upgrade from any release to an alpha release or from an alpha
release to any other release will most likely require a
dump/restore upgrade procedure. It may happen that this is not
necessary in particular cases, but that is not verified beforehand.
(The server will warn you in any case when a dump/restore is
necessary if you attempt to use it with an old data directory.)
Note, however, that the dump/restore upgrade procedure is expected
to work for alpha releases, and problems in this area should be
reported.
Testing
The primary reason we release alphas is to get users to test new
features as early as possible. If you are interested in helping
with organized testing, please see
the
testing information page.
Changes
SQL Features
Add SQL-compliant triggers on columns, which fire only if
certain columns are named in the UPDATE's SET list.>
Add CREATE LIKE INCLUDING COMMENTS and STORAGE, and INCLUDING
ALL shortcut to allow users to make an exact copy of a table including
all options and features.>
Define a new, more extensible syntax for COPY options
in order to support additional COPY options in the future.>
Modify the definition of window-function PARTITION
BY and ORDER BY clauses so that their elements are always
taken as simple expressions over the query's input
columns. This fixes a bug.>
Fix bug with nested WITH RECURSIVE statements.>
Add surrogate pair support for U& string and identifier
syntax.>
Add Unicode escapes in E'...' strings.>
DROP COLUMN and DROP CONSTRAINT now support an IF EXISTS clause so
that users can avoid fatal errors when running repeatable scripts.
UNIQUE constraints can now be DEFERRABLE. This is primarily useful
for incremental updates of numerical keys, e.g. "ID = ID +
1"
Allow parentheses around the query _expression_ that follows a WITH
clause.
INFORMATION_SCHEMA, a catalog of standard views of database
objects, has been updated to the SQL:2008 standard.
Change character_octet_length to more sensible values in
INFORMATION_SCHEMA.
Allow * as parameter for FORCE QUOTE for COPY CSV, so that all
columns will be quoted.
Performance
Make TRUNCATE do truncate-in-place when processing
a relation that was created or previously truncated in the
current (sub)transaction.>
Implement "join removal" for cases where the inner side
of a left join is unique and is not referenced above the join. This should
speed up many ORM-generated and reporting tool queries.
Remove the use of the flat files pg_auth and
pg_database in order to improve performance. (Warning: pgbouncer
and possibly other tools currently suggest referring to the pg_auth
file for its user database. Such schemes will no longer work.)
EXPLAIN allows output of plans in XML or JSON format for automated
processing of explain plans by analysis or visualization tools.
EXPLAIN now supports the use of generic options in EXPLAIN ( option
value, ... ) format, which permits the creation of additional
EXPLAIN options.
ALTER TABLE ... ALTER COLUMN ... SET STATISTICS DISTINCT allows
users to manually tweak the number of distinct values estimated for
a column, to fix cases where ANALYZE estimates are incorrect.
Make GEQO's planning deterministic by having it start from a
predictable random number seed each time.
Rewrite GEQO's gimme_tree function so that it always finds a legal
join sequence. Previously, it could have failed to produce a plan
in some cases.
Tweak TOAST code so that columns marked with MAIN storage strategy
are not forced out-of-line unless that is necessary to make the row
fit on a page. Previously, they were forced out-of-line if needed
to get the row down to the default target size (1/4th page).
Simplify the forms foo <> true and foo <> false to foo
= false and foo = true during query optimization.
Avoid per-send() system calls to manage SIGPIPE in libpq, if the
platform provides either sockopt(SO_NOSIGPIPE) or the MSG_NOSIGNAL
flag to send().
Administration and Monitoring
Add a Boolean server configuration parameter
"bonjour" to control whether a Bonjour-enabled
build actually attempts to advertise itself via Bonjour.>
When reloading postgresql.conf, log what parameters actually
changed.>
Make it possibly to specify server configuration parameters
per user-database combination. Add a "drds" command to psql to
display the settings.>
Allow the collection of statistics on sequences.>
Increase the maximum value of extra_float_digits to
3, and have pg_dump use that value when the backend is new
enough to allow it, because it is possible to need 3 extra
digits for float4 values (but not for float8 values).>
Add the ability to include the SQLSTATE error code of any error
messages in the PostgreSQL activity log with the new
log_line_prefix placeholder %e.
Show the exact value being complained of in
unique-constraint-violation error messages, including unique-index
build failures.
Security
Add ALTER DEFAULT PRIVILEGES command, which allows
users to adjust the privileges that will be applied to
subsequently-created objects.>
Add GRANT/REVOKE ON ALL TABLES/SEQUENCES/FUNCTIONS IN SCHEMA.
This makes it easier to manage permissions on database objects.
Support "samehost" and "samenet" specifications
in pg_hba.conf. This allows users with dynamic server addresses to run
PostgreSQL without frequently modifying pg_hba.conf
New has_sequence_privilege() functions allow you to check sequence
privileges for a given ROLE.
Built-In Functions
Support POSIX-compatible interpretation of ? as well as {m,n}
and related constructs in SIMILAR TO, per SQL:2008.>
The to_char() formatting functions now supports EEEE (scientific
notation).
Use floor() not rint() when reducing precision of fractional
seconds in timestamp_trunc, timestamptz_trunc, and interval_trunc()
for the float-datetime case. This improves accuracy of time
calculations.
Fix ancient bug in handling of to_char() modifier 'TH', when used
with HH.
Data Types
Fix encoding handling in binary input function of xml type.>
Tighten binary receive functions so that they reject values
that the text input functions don't accept either.>
New hex-string input and output format options for type bytea. Hex
output format is enabled by default, which is an incompatible
change. See the new bytea_output parameter if you need to restore
compatibility.
Adds prefix support for text search synonym dictionary, allowing
creation of synonyms on partial matches.
Server Tools
It is now reasonably safe to use pg_ctl to start
the postmaster from a boot-time script.
pg_dump/pg_restore --clean now drops large objects.
Modify parallel pg_restore ordering logic to avoid a potential
O(N^2) slowdown for some complex databases.
psql
Implement significantly saner behavior when two or
more psql sessions overlap in their use of the history file.>
Add "pset linestyle ascii/unicode" option to psql,
allowing our traditional ASCII-art style of table output to
be upgraded to use Unicode box drawing characters if
desired. By default, psql will use the Unicode characters
whenever client_encoding is UTF8.>
Have \d show child tables that inherit from the specified parent
psql now shows the index methods in \di
Procedural Languages
Add DO statement to support execution of procedural language
code without having to create a function for it.>
Support use of function argument names to identify which
actual arguments match which function parameters. The syntax
uses AS, for example funcname(value AS arg1, anothervalue AS
arg2).>
Fix/improve bytea and boolean support in PL/Python. Data type
conversion into and out of PL/Python previously went through
an intermediate string representation, which caused various
discrepancies especially with bytea and boolean data. This is
now fixed by converting the values directly.>
PL/Python now accepts Unicode objects where it previously
only accepted string objects (for example, as return
value). Unicode objects are converted to the PostgreSQL
server encoding as necessary.>
Improve error context reporting in PL/Perl, for
easier debugging.>
PL/pgSQL IN parameters now accept value assignments.>
Convert a Perl array to a PostgreSQL array when returned by
set-returning functions as well as non-SRFs.>
Allow cursor commands MOVE FORWARD n, MOVE BACKWARD n,
MOVE FORWARD ALL, MOVE BACKWARD ALL in PL/pgSQL.>
PL/pgSQL functions can now better cope with row types
containing dropped columns.
Improve error context reporting in PL/Python, for easier
debugging.
Greatly expand the regression testing for PL/Python.
Additional Supplied Modules
Multiple improvements in contrib/hstore, including
raising limits on keys and values, conversions to and from
records and arrays, and support for GROUP BY and DISTINCT.
pgbench is now multi-threaded, allowing it to use multiple CPU's
for its client connections, and to do more realistic workload
testing.
Added the ability to retrieve asynchronous notifications using
dblink, via the addition of the function dblink_get_notify().
Added matchorig, matchsynonyms, and keepsynonyms options to
contrib/dict_xsyn.
Added contrib/unaccent.
Development
Add ECPG function that returns the current transaction status.>
Make ECPG more robust against applications freeing strings.>
Make libpq reject non-numeric and out-of-range port numbers with a
suitable error message.
Functions which conflict with C++ reserved words have been renamed,
making backend header files now safe to use with C++ libraries.
Add man pages for SPI functions.
ECPG now includes a STRING datatype for Informix compatibility
mode.
Ports
Change the WIN32 API version to be 5.01 (Windows XP), to
bring in the proper IPv6 headers in newer SDKs.>
Write to the Windows eventlog in UTF-16, converting the
message encoding as necessary.>
Replace use of the long-deprecated Bonjour API
DNSServiceRegistrationCreate with the not-so-deprecated
DNSServiceRegister. The new code will fail on Mac OS X
releases before 10.3.>
Install a hopefully-temporary workaround for Mac OS X Snow Leopard
readdir() bug.>
Reserve the shared memory region during backend startup on Windows,
so that memory allocated by starting third party DLLs doesn't end
up conflicting with it. Hopefully this solves the long-time issue
with "could not reattach to shared memory" errors on
Win32.
Add s_lock support for SuperH architecture (not well tested).
Source code, build options
Fix inclusions of readline/editline header files so that we
only attempt to #include the version of history.h that is in
the same directory as the readline.h we are using. This
avoids problems in some scenarios where both readline and
editline are installed.>
Derived files that are shipped in the distribution used to be
built in the source directory even for out-of-tree
builds. They are now also built in the build tree. This
should be more convenient for certain developers' workflows.>
Translations were updated.>
Upgrade to Autoconf 2.63 (not relevant to users of distribution
tarballs).
Minimum version of Flex is now 2.5.31, to support reentrant
scanners (not relevant to users of distribution tarballs).
Documentation build rules have been improved. The generated
documentation files are now shipped "loose", not in
sub-tarballs.
New toolchain to generate man pages. From now on, the man pages
will be current in every release.
Code-coverage testing support now extends to the entire source
tree, not only src/backend/.
Make the core scanner re-entrant, along with additional fixes that
will let it be used directly by PL/pgSQL.
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