2008年2月 5日

[installer 1414] postgresql-8.3.0

postgresql-8.3.0 出ています。

☆ postgresql-8.3.0
http://www.postgresql.org/
ftp://ftp.postgresql.org/pub/source/v8.3.0/postgresql-8.3.0.tar.gz

Release 8.3

Release date: 2008-02-04
__________________________________________________________________

Overview

With significant new functionality and performance enhancements, this
release represents a major leap forward for PostgreSQL. This was made
possible by a growing community that has dramatically accelerated the
pace of development. This release adds the following major features:

* Full text search is integrated into the core database system
* Support for the SQL/XML standard, including new operators and an
XML data type
* Enumerated data types (ENUM)
* Arrays of composite types
* Universally Unique Identifier (UUID) data type
* Add control over whether NULLs sort first or last
* Updatable cursors
* Server configuration parameters can now be set on a per-function
basis
* User-defined types can now have type modifiers
* Automatically re-plan cached queries when table definitions change
or statistics are updated
* Numerous improvements in logging and statistics collection
* Support Security Service Provider Interface (SSPI) for
authentication on Windows
* Support multiple concurrent autovacuum processes, and other
autovacuum improvements
* Allow the whole PostgreSQL distribution to be compiled with
Microsoft Visual C++

Major performance improvements are listed below. Most of these
enhancements are automatic and do not require user changes or tuning:

* Asynchronous commit delays writes to WAL during transaction commit
* Checkpoint writes can be spread over a longer time period to smooth
the I/O spike during each checkpoint
* Heap-Only Tuples (HOT) accelerate space reuse for most "UPDATE"s
and "DELETE"s
* Just-in-time background writer strategy improves disk write
efficiency
* Using non-persistent transaction IDs for read-only transactions
reduces overhead and "VACUUM" requirements
* Per-field and per-row storage overhead has been reduced
* Large sequential scans no longer force out frequently used cached
pages
* Concurrent large sequential scans can now share disk reads
* ORDER BY ... LIMIT can be done without sorting

The above items are explained in more detail in the sections below.
__________________________________________________________________

Migration to Version 8.3

A dump/restore using pg_dump is required for those wishing to migrate
data from any previous release.

Observe the following incompatibilities:
__________________________________________________________________

General

* Non-character data types are no longer automatically cast to TEXT
(Peter, Tom)
Previously, if a non-character value was supplied to an operator or
function that requires text input, it was automatically cast to
text, for most (though not all) built-in data types. This no longer
happens: an explicit cast to text is now required for all
non-character-string types. For example, these expressions formerly
worked:
substr(current_date, 1, 4)
23 LIKE '2%'
but will now draw "function does not exist" and "operator does not
exist" errors respectively. Use an explicit cast instead:
substr(current_date::text, 1, 4)
23::text LIKE '2%'
(Of course, you can use the more verbose CAST() syntax too.) The
reason for the change is that these automatic casts too often
caused surprising behavior. An example is that in previous
releases, this expression was accepted but did not do what was
expected:
current_date < 2017-11-17
This is actually comparing a date to an integer, which should be
(and now is) rejected -- but in the presence of automatic casts
both sides were cast to text and a textual comparison was done,
because the text < text operator was able to match the expression
when no other < operator could.
Types char(n) and varchar(n) still cast to text automatically.
Also, automatic casting to text still works for inputs to the
concatenation (||) operator, so long as least one input is a
character-string type.
* Full text search features from "contrib/tsearch2" have been moved
into the core server, with some minor syntax changes
"contrib/tsearch2" now contains a compatibility interface.
* ARRAY(SELECT ...), where the "SELECT" returns no rows, now returns
an empty array, rather than NULL (Tom)
* The array type name for a base data type is no longer always the
base type's name with an underscore prefix
The old naming convention is still honored when possible, but
application code should no longer depend on it. Instead use the new
pg_type.typarray column to identify the array data type associated
with a given type.
* ORDER BY ... USING "operator" must now use a less-than or
greater-than "operator" that is defined in a btree operator class
This restriction was added to prevent inconsistent results.
* "SET LOCAL" changes now persist until the end of the outermost
transaction, unless rolled back (Tom)
Previously "SET LOCAL"'s effects were lost after subtransaction
commit ("RELEASE SAVEPOINT" or exit from a PL/pgSQL exception
block).
* Commands rejected in transaction blocks are now also rejected in
multiple-statement query strings (Tom)
For example, "BEGIN; DROP DATABASE; COMMIT" will now be rejected
even if submitted as a single query message.
* "ROLLBACK" outside a transaction block now issues NOTICE instead of
WARNING (Bruce)
* Prevent "NOTIFY"/"LISTEN"/"UNLISTEN" from accepting
schema-qualified names (Bruce)
Formerly, these commands accepted schema.relation but ignored the
schema part, which was confusing.
* "ALTER SEQUENCE" no longer affects the sequence's currval() state
(Tom)
* Foreign keys now must match indexable conditions for
cross-data-type references (Tom)
This improves semantic consistency and helps avoid performance
problems.
* Restrict object size functions to users who have reasonable
permissions to view such information (Tom)
For example, pg_database_size() now requires CONNECT permission,
which is granted to everyone by default. pg_tablespace_size()
requires CREATE permission in the tablespace, or is allowed if the
tablespace is the default tablespace for the database.
* Remove the undocumented !!= (not in) operator (Tom)
NOT IN (SELECT ...) is the proper way to perform this operation.
* Internal hashing functions are now more uniformly-distributed (Tom)
If application code was computing and storing hash values using
internal PostgreSQL hashing functions, the hash values must be
regenerated.
* C-code conventions for handling variable-length data values have
changed (Greg Stark, Tom)
The new SET_VARSIZE() macro *must* be used to set the length of
generated varlena values. Also, it might be necessary to expand
("de-TOAST") input values in more cases.
* Continuous archiving no longer reports each successful archive
operation to the server logs unless DEBUG level is used (Simon)
__________________________________________________________________

Configuration Parameters

* Numerous changes in administrative server parameters
bgwriter_lru_percent, bgwriter_all_percent, bgwriter_all_maxpages,
stats_start_collector, and stats_reset_on_server_start are removed.
redirect_stderr is renamed to logging_collector.
stats_command_string is renamed to track_activities.
stats_block_level and stats_row_level are merged into track_counts.
A new boolean configuration parameter, archive_mode, controls
archiving. Autovacuum's default settings have changed.
* Remove stats_start_collector parameter (Tom)
We now always start the collector process, unless UDP socket
creation fails.
* Remove stats_reset_on_server_start parameter (Tom)
This was removed because pg_stat_reset() can be used for this
purpose.
* Commenting out a parameter in "postgresql.conf" now causes it to
revert to its default value (Joachim Wieland)
Previously, commenting out an entry left the parameter's value
unchanged until the next server restart.
__________________________________________________________________

Character Encodings

* Add more checks for invalidly-encoded data (Andrew)
This change plugs some holes that existed in literal backslash
escape string processing and "COPY" escape processing. Now the
de-escaped string is rechecked to see if the result created an
invalid multi-byte character.
* Disallow database encodings that are inconsistent with the server's
locale setting (Tom)
On most platforms, C locale is the only locale that will work with
any database encoding. Other locale settings imply a specific
encoding and will misbehave if the database encoding is something
different. (Typical symptoms include bogus textual sort order and
wrong results from upper() or lower().) The server now rejects
attempts to create databases that have an incompatible encoding.
* Ensure that chr() cannot create invalidly-encoded values (Andrew)
In UTF8-encoded databases the argument of chr() is now treated as a
Unicode code point. In other multi-byte encodings chr()'s argument
must designate a 7-bit ASCII character. Zero is no longer accepted.
ascii() has been adjusted to match.
* Adjust convert() behavior to ensure encoding validity (Andrew)
The two argument form of convert() has been removed. The three
argument form now takes a bytea first argument and returns a bytea.
To cover the loss of functionality, three new functions have been
added:
+ convert_from(bytea, name) returns text -- converts the first
argument from the named encoding to the database encoding
+ convert_to(text, name) returns bytea -- converts the first
argument from the database encoding to the named encoding
+ length(bytea, name) returns integer -- gives the length of the
first argument in characters in the named encoding
* Remove convert(argument USING conversion_name) (Andrew)
Its behavior did not match the SQL standard.
* Make JOHAB encoding client-only (Tatsuo)
JOHAB is not safe as a server-side encoding.
__________________________________________________________________

Changes

Below you will find a detailed account of the changes between
PostgreSQL 8.3 and the previous major release.
__________________________________________________________________

Performance

* Asynchronous commit delays writes to WAL during transaction commit
(Simon)
This feature dramatically increases performance for short
data-modifying transactions. The disadvantage is that because disk
writes are delayed, if the operating system crashes before data is
written to the disk, committed data will be lost. This feature is
useful for applications that can accept some data loss. Unlike
turning off fsync, asynchronous commit does not put database
consistency at risk; the worst case is that after a database or
system crash the last few reportedly-committed transactions might
be missing. This feature is enabled by turning off
synchronous_commit (which can be done per-session or
per-transaction, if some transactions are critical and others are
not). wal_writer_delay can be adjusted to control the maximum delay
before transactions actually reach disk.
* Checkpoint writes can be spread over a longer time period to smooth
the I/O spike during each checkpoint (Itagaki Takahiro and Heikki
Linnakangas)
Previously all modified buffers were forced to disk as quickly as
possible during a checkpoint, causing an I/O spike that decreased
server performance. This new approach spreads out disk writes
during checkpoints, reducing peak I/O usage. (User-requested and
shutdown checkpoints are still written as quickly as possible.)
* Heap-Only Tuples (HOT) accelerate space reuse for most "UPDATE"s
and "DELETE"s (Pavan Deolasee, with ideas from many others)
"UPDATE"s and "DELETE"s leave dead tuples behind, as do failed
"INSERT"s. Previously only "VACUUM" could reclaim space taken by
dead tuples. With HOT dead tuple space can be reclaimed at the time
of "INSERT" or "UPDATE" if no changes are made to indexed columns.
This allows for more consistent performance. Also, HOT avoids
adding duplicate index entries.
* Just-in-time background writer strategy improves disk write
efficiency (Greg Smith, Itagaki Takahiro)
This greatly reduces the need for manual tuning of the background
writer.
* Per-field and per-row storage overhead have been reduced (Greg
Stark, Heikki Linnakangas)
Variable-length data types with data values less than 128 bytes
long will see a storage decrease of 3 to 6 bytes. For example, two
adjacent char(1) fields now use 4 bytes instead of 16. Row headers
are also 4 bytes shorter than before.
* Using non-persistent transaction IDs for read-only transactions
reduces overhead and "VACUUM" requirements (Florian Pflug)
Non-persistent transaction IDs do not increment the global
transaction counter. Therefore, they reduce the load on pg_clog and
increase the time between forced vacuums to prevent transaction ID
wraparound. Other performance improvements were also made that
should improve concurrency.
* Avoid incrementing the command counter after a read-only command
(Tom)
There was formerly a hard limit of 2^32 (4 billion) commands per
transaction. Now only commands that actually changed the database
count, so while this limit still exists, it should be significantly
less annoying.
* Create a dedicated WAL writer process to off-load work from
backends (Simon)
* Skip unnecessary WAL writes for "CLUSTER" and "COPY" (Simon)
Unless WAL archiving is enabled, the system now avoids WAL writes
for "CLUSTER" and just fsync()s the table at the end of the
command. It also does the same for "COPY" if the table was created
in the same transaction.
* Large sequential scans no longer force out frequently used cached
pages (Simon, Heikki, Tom)
* Concurrent large sequential scans can now share disk reads (Jeff
Davis)
This is accomplished by starting the new sequential scan in the
middle of the table (where another sequential scan is already
in-progress) and wrapping around to the beginning to finish. This
can affect the order of returned rows in a query that does not
specify ORDER BY. The synchronize_seqscans configuration parameter
can be used to disable this if necessary.
* ORDER BY ... LIMIT can be done without sorting (Greg Stark)
This is done by sequentially scanning the table and tracking just
the "top N" candidate rows, rather than performing a full sort of
the entire table. This is useful when there is no matching index
and the LIMIT is not large.
* Put a rate limit on messages sent to the statistics collector by
backends (Tom)
This reduces overhead for short transactions, but might sometimes
increase the delay before statistics are tallied.
* Improve hash join performance for cases with many NULLs (Tom)
* Speed up operator lookup for cases with non-exact datatype matches
(Tom)
__________________________________________________________________

Server

* Autovacuum is now enabled by default (Alvaro)
Several changes were made to eliminate disadvantages of having
autovacuum enabled, thereby justifying the change in default.
Several other autovacuum parameter defaults were also modified.
* Support multiple concurrent autovacuum processes (Alvaro, Itagaki
Takahiro)
This allows multiple vacuums to run concurrently. This prevents
vacuuming of a large table from delaying vacuuming of smaller
tables.
* Automatically re-plan cached queries when table definitions change
or statistics are updated (Tom)
Previously PL/PgSQL functions that referenced temporary tables
would fail if the temporary table was dropped and recreated between
function invocations, unless EXECUTE was used. This improvement
fixes that problem and many related issues.
* Add a temp_tablespaces parameter to control the tablespaces for
temporary tables and files (Jaime Casanova, Albert Cervera, Bernd
Helmle)
This parameter defines a list of tablespaces to be used. This
enables spreading the I/O load across multiple tablespaces. A
random tablespace is chosen each time a temporary object is
created. Temporary files are no longer stored in per-database
"pgsql_tmp/" directories but in per-tablespace directories.
* Place temporary tables' TOAST tables in special schemas named
pg_toast_temp_nnn (Tom)
This allows low-level code to recognize these tables as temporary,
which enables various optimizations such as not WAL-logging changes
and using local rather than shared buffers for access. This also
fixes a bug wherein backends unexpectedly held open file references
to temporary TOAST tables.
* Fix problem that a constant flow of new connection requests could
indefinitely delay the postmaster from completing a shutdown or a
crash restart (Tom)
* Guard against a very-low-probability data loss scenario by
preventing re-use of a deleted table's relfilenode until after the
next checkpoint (Heikki)
* Fix "CREATE CONSTRAINT TRIGGER" to convert old-style foreign key
trigger definitions into regular foreign key constraints (Tom)
This will ease porting of foreign key constraints carried forward
from pre-7.3 databases, if they were never converted using
"contrib/adddepend".
* Fix DEFAULT NULL to override inherited defaults (Tom)
DEFAULT NULL was formerly considered a noise phrase, but it should
(and now does) override non-null defaults that would otherwise be
inherited from a parent table or domain.
* Add new encodings EUC_JIS_2004 and SHIFT_JIS_2004 (Tatsuo)
These new encodings can be converted to and from UTF-8.
* Change server startup log message from "database system is ready"
to "database system is ready to accept connections", and adjust its
timing
The message now appears only when the postmaster is really ready to
accept connections.
__________________________________________________________________

Monitoring

* Add log_autovacuum_min_duration parameter to support configurable
logging of autovacuum activity (Simon, Alvaro)
* Add log_lock_waits parameter to log lock waiting (Simon)
* Add log_temp_files parameter to log temporary file usage (Bill
Moran)
* Add log_checkpoints parameter to improve logging of checkpoints
(Greg Smith, Heikki)
* log_line_prefix now supports %s and %c escapes in all processes
(Andrew)
Previously these escapes worked only for user sessions, not for
background database processes.
* Add log_restartpoints to control logging of point-in-time recovery
restart points (Simon)
* Last transaction end time is now logged at end of recovery and at
each logged restart point (Simon)
* Autovacuum now reports its activity start time in pg_stat_activity
(Tom)
* Allow server log output in comma-separated value (CSV) format (Arul
Shaji, Greg Smith, Andrew Dunstan)
CSV-format log files can easily be loaded into a database table for
subsequent analysis.
* Use PostgreSQL-supplied timezone support for formatting timestamps
displayed in the server log (Tom)
This avoids Windows-specific problems with localized time zone
names that are in the wrong encoding. There is a new log_timezone
parameter that controls the timezone used in log messages,
independently of the client-visible timezone parameter.
* New system view pg_stat_bgwriter displays statistics about
background writer activity (Magnus)
* Add new columns for database-wide tuple statistics to
pg_stat_database (Magnus)
* Add an xact_start (transaction start time) column to
pg_stat_activity (Neil)
This makes it easier to identify long-running transactions.
* Add n_live_tuples and n_dead_tuples columns to pg_stat_all_tables
and related views (Glen Parker)
* Merge stats_block_level and stats_row_level parameters into a
single parameter track_counts, which controls all messages sent to
the statistics collector process (Tom)
* Rename stats_command_string parameter to track_activities (Tom)
* Fix statistical counting of live and dead tuples to recognize that
committed and aborted transactions have different effects (Tom)
__________________________________________________________________

Authentication

* Support Security Service Provider Interface (SSPI) for
authentication on Windows (Magnus)
* Support GSSAPI authentication (Henry Hotz, Magnus)
This should be preferred to native Kerberos authentication because
GSSAPI is an industry standard.
* Support a global SSL configuration file (Victor Wagner)
* Add ssl_ciphers parameter to control accepted SSL ciphers (Victor
Wagner)
* Add a Kerberos realm parameter, krb_realm (Magnus)
__________________________________________________________________

Write-Ahead Log (WAL) and Continuous Archiving

* Change the timestamps recorded in transaction WAL records from
time_t to TimestampTz representation (Tom)
This provides sub-second resolution in WAL, which can be useful for
point-in-time recovery.
* Reduce WAL disk space needed by warm standby servers (Simon)
This change allows a warm standby server to pass the name of the
earliest still-needed WAL file to the recovery script, allowing
automatic removal of no-longer-needed WAL files. This is done using
%r in the restore_command parameter of "recovery.conf".
* New boolean configuration parameter, archive_mode, controls
archiving (Simon)
Previously setting archive_command to an empty string turned off
archiving. Now archive_mode turns archiving on and off,
independently of archive_command. This is useful for stopping
archiving temporarily.
__________________________________________________________________

Queries

* Full text search is integrated into the core database system
(Teodor, Oleg)
Text search has been improved, moved into the core code, and is now
installed by default. "contrib/tsearch2" now contains a
compatibility interface.
* Add control over whether NULLs sort first or last (Teodor, Tom)
The syntax is ORDER BY ... NULLS FIRST/LAST.
* Allow per-column ascending/descending (ASC/DESC) ordering options
for indexes (Teodor, Tom)
Previously a query using ORDER BY with mixed ASC/DESC specifiers
could not fully use an index. Now an index can be fully used in
such cases if the index was created with matching ASC/DESC
specifications. NULL sort order within an index can be controlled,
too.
* Allow col IS NULL to use an index (Teodor)
* Updatable cursors (Arul Shaji, Tom)
This eliminates the need to reference a primary key to "UPDATE" or
"DELETE" rows returned by a cursor. The syntax is UPDATE/DELETE
WHERE CURRENT OF.
* Allow FOR UPDATE in cursors (Arul Shaji, Tom)
* Create a general mechanism that supports casts to and from the
standard string types (TEXT, VARCHAR, CHAR) for *every* datatype,
by invoking the datatype's I/O functions (Tom)
Previously, such casts were available only for types that had
specialized function(s) for the purpose. These new casts are
assignment-only in the to-string direction, explicit-only in the
other direction, and therefore should create no surprising
behavior.
* Allow UNION and related constructs to return a domain type, when
all inputs are of that domain type (Tom)
Formerly, the output would be considered to be of the domain's base
type.
* Allow limited hashing when using two different data types (Tom)
This allows hash joins, hash indexes, hashed subplans, and hash
aggregation to be used in situations involving cross-data-type
comparisons, if the data types have compatible hash functions.
Currently, cross-data-type hashing support exists for
smallint/integer/bigint, and for float4/float8.
* Improve optimizer logic for detecting when variables are equal in a
WHERE clause (Tom)
This allows mergejoins to work with descending sort orders, and
improves recognition of redundant sort columns.
* Improve performance when planning large inheritance trees in cases
where most tables are excluded by constraints (Tom)
__________________________________________________________________

Object Manipulation

* Arrays of composite types (David Fetter, Andrew, Tom)
In addition to arrays of explicitly-declared composite types,
arrays of the rowtypes of regular tables and views are now
supported, except for rowtypes of system catalogs, sequences, and
TOAST tables.
* Server configuration parameters can now be set on a per-function
basis (Tom)
For example, functions can now set their own search_path to prevent
unexpected behavior if a different search_path exists at run-time.
Security definer functions should set search_path to avoid security
loopholes.
* "CREATE/ALTER FUNCTION" now supports COST and ROWS options (Tom)
COST allows specification of the cost of a function call. ROWS
allows specification of the average number or rows returned by a
set-returning function. These values are used by the optimizer in
choosing the best plan.
* Implement "CREATE TABLE LIKE ... INCLUDING INDEXES" (Trevor
Hardcastle, Nikhil Sontakke, Neil)
* Allow "CREATE INDEX CONCURRENTLY" to ignore transactions in other
databases (Simon)
* Add "ALTER VIEW ... RENAME TO" and "ALTER SEQUENCE ... RENAME TO"
(David Fetter, Neil)
Previously this could only be done via "ALTER TABLE ... RENAME TO".
* Make "CREATE/DROP/RENAME DATABASE" wait briefly for conflicting
backends to exit before failing (Tom)
This increases the likelihood that these commands will succeed.
* Allow triggers and rules to be deactivated in groups using a
configuration parameter, for replication purposes (Jan)
This allows replication systems to disable triggers and rewrite
rules as a group without modifying the system catalogs directly.
The behavior is controlled by "ALTER TABLE" and a new parameter
session_replication_role.
* User-defined types can now have type modifiers (Teodor, Tom)
This allows a user-defined type to take a modifier, like ssnum(7).
Previously only built-in data types could have modifiers.
__________________________________________________________________

Utility Commands

* Non-superuser database owners now are able to add trusted
procedural languages to their databases by default (Jeremy Drake)
While this is reasonably safe, some administrators might wish to
revoke the privilege. It is controlled by
pg_pltemplate.tmpldbacreate.
* Allow a session's current parameter setting to be used as the
default for future sessions (Tom)
This is done with SET ... FROM CURRENT in "CREATE/ALTER FUNCTION",
"ALTER DATABASE", or "ALTER ROLE".
* Implement new commands "DISCARD ALL", "DISCARD PLANS", "DISCARD
TEMPORARY", "CLOSE ALL", and "DEALLOCATE ALL" (Marko Kreen, Neil)
These commands simplify resetting a database session to its initial
state, and are particularly useful for connection-pooling software.
* Make "CLUSTER" MVCC-safe (Heikki Linnakangas)
Formerly, "CLUSTER" would discard all tuples that were committed
dead, even if there were still transactions that should be able to
see them under MVCC visibility rules.
* Add new "CLUSTER" syntax: CLUSTER table USING index (Holger
Schurig)
The old "CLUSTER" syntax is still supported, but the new form is
considered more logical.
* Fix "EXPLAIN" so it can show complex plans more accurately (Tom)
References to subplan outputs are now always shown correctly,
instead of using ?columnN? for complicated cases.
* Limit the amount of information reported when a user is dropped
(Alvaro)
Previously, dropping (or attempting to drop) a user who owned many
objects could result in large NOTICE or ERROR messages listing all
these objects; this caused problems for some client applications.
The length of the message is now limited, although a full list is
still sent to the server log.
__________________________________________________________________

Data Types

* Support for the SQL/XML standard, including new operators and an
XML data type (Nikolay Samokhvalov, Pavel Stehule, Peter)
* Enumerated data types (ENUM) (Tom Dunstan)
This feature provides convenient support for fields that have a
small, fixed set of allowed values. An example of creating an ENUM
type is CREATE TYPE mood AS ENUM ('sad', 'ok', 'happy').
* Universally Unique Identifier (UUID) data type (Gevik Babakhani,
Neil)
This closely matches RFC 4122.
* Widen the MONEY data type to 64 bits (D'Arcy Cain)
This greatly increases the range of supported MONEY values.
* Fix float4/float8 to handle Infinity and NAN (Not A Number)
consistently (Bruce)
The code formerly was not consistent about distinguishing Infinity
from overflow conditions.
* Allow leading and trailing whitespace during input of boolean
values (Neil)
* Prevent "COPY" from using digits and lowercase letters as
delimiters (Tom)
__________________________________________________________________

Functions

* Add new regular expression functions regexp_matches(),
regexp_split_to_array(), and regexp_split_to_table() (Jeremy Drake,
Neil)
These functions provide extraction of regular expression
subexpressions and allow splitting a string using a POSIX regular
expression.
* Add lo_truncate() for large object truncation (Kris Jurka)
* Implement width_bucket() for the float8 data type (Neil)
* Add pg_stat_clear_snapshot() to discard statistics snapshots
collected during the current transaction (Tom)
The first request for statistics in a transaction takes a
statistics snapshot that does not change during the transaction.
This function allows the snapshot to be discarded and a new
snapshot loaded during the next statistics query. This is
particularly useful for PL/PgSQL functions, which are confined to a
single transaction.
* Add isodow option to EXTRACT() and date_part() (Bruce)
This returns the day of the week, with Sunday as seven. (dow
returns Sunday as zero.)
* Add ID (ISO day of week) and IDDD (ISO day of year) format codes
for to_char(), to_date(), and to_timestamp() (Brendan Jurd)
* Make to_timestamp() and to_date() assume TM (trim) option for
potentially variable-width fields (Bruce)
This matches Oracle's behavior.
* Fix off-by-one conversion error in to_date()/to_timestamp() D
(non-ISO day of week) fields (Bruce)
* Make setseed() return void, rather than a useless integer value
(Neil)
* Add a hash function for NUMERIC (Neil)
This allows hash indexes and hash-based plans to be used with
NUMERIC columns.
* Improve efficiency of LIKE/ILIKE, especially for multi-byte
character sets like UTF-8 (Andrew, Itagaki Takahiro)
* Make currtid() functions require SELECT privileges on the target
table (Tom)
* Add several txid_*() functions to query active transaction IDs
(Jan)
This is useful for various replication solutions.
__________________________________________________________________

PL/PgSQL Server-Side Language

* Add scrollable cursor support, including directional control in
"FETCH" (Pavel Stehule)
* Allow IN as an alternative to FROM in PL/PgSQL's "FETCH" statement,
for consistency with the backend's "FETCH" command (Pavel Stehule)
* Add "MOVE" to PL/PgSQL (Magnus, Pavel Stehule, Neil)
* Implement "RETURN QUERY" (Pavel Stehule, Neil)
This adds convenient syntax for PL/PgSQL set-returning functions
that want to return the result of a query. "RETURN QUERY" is easier
and more efficient than a loop around "RETURN NEXT".
* Allow function parameter names to be qualified with the function's
name (Tom)
For example, myfunc.myvar. This is particularly useful for
specifying variables in a query where the variable name might match
a column name.
* Make qualification of variables with block labels work properly
(Tom)
Formerly, outer-level block labels could unexpectedly interfere
with recognition of inner-level record or row references.
* Tighten requirements for FOR loop STEP values (Tom)
Prevent non-positive STEP values, and handle loop overflows.
* Improve accuracy when reporting syntax error locations (Tom)
__________________________________________________________________

Other Server-Side Languages

* Allow type-name arguments to PL/Perl spi_prepare() to be data type
aliases in addition to names found in pg_type (Andrew)
* Allow type-name arguments to PL/Python plpy.prepare() to be data
type aliases in addition to names found in pg_type (Andrew)
* Allow type-name arguments to PL/Tcl spi_prepare to be data type
aliases in addition to names found in pg_type (Andrew)
* Enable PL/PythonU to compile on Python 2.5 (Marko Kreen)
* Support a true PL/Python boolean type in compatible Python versions
(Python 2.3 and later) (Marko Kreen)
* Fix PL/Tcl problems with thread-enabled "libtcl" spawning multiple
threads within the backend (Steve Marshall, Paul Bayer, Doug
Knight)
This caused all sorts of unpleasantness.
__________________________________________________________________

psql

* List disabled triggers separately in \d output (Brendan Jurd)
* In \d patterns, always match $ literally (Tom)
* Show aggregate return types in \da output (Greg Sabino Mullane)
* Add the function's volatility status to the output of \df+ (Neil)
* Add \prompt capability (Chad Wagner)
* Allow \pset, \t, and \x to specify on or off, rather than just
toggling (Chad Wagner)
* Add \sleep capability (Jan)
* Enable \timing output for \copy (Andrew)
* Improve \timing resolution on Windows (Itagaki Takahiro)
* Flush \o output after each backslash command (Tom)
* Correctly detect and report errors while reading a -f input file
(Peter)
* Remove -u option (this option has long been deprecated) (Tom)
__________________________________________________________________

pg_dump

* Add --tablespaces-only and --roles-only options to pg_dumpall (Dave
Page)
* Add an output file option to pg_dumpall (Dave Page)
This is primarily useful on Windows, where output redirection of
child pg_dump processes does not work.
* Allow pg_dumpall to accept an initial-connection database name
rather than the default template1 (Dave Page)
* In -n and -t switches, always match $ literally (Tom)
* Improve performance when a database has thousands of objects (Tom)
* Remove -u option (this option has long been deprecated) (Tom)
__________________________________________________________________

Other Client Applications

* In initdb, allow the location of the "pg_xlog" directory to be
specified (Euler Taveira de Oliveira)
* Enable server core dump generation in pg_regress on supported
operating systems (Andrew)
* Add a -t (timeout) parameter to pg_ctl (Bruce)
This controls how long pg_ctl will wait when waiting for server
startup or shutdown. Formerly the timeout was hard-wired as 60
seconds.
* Add a pg_ctl option to control generation of server core dumps
(Andrew)
* Allow Control-C to cancel clusterdb, reindexdb, and vacuumdb
(Itagaki Takahiro, Magnus)
* Suppress command tag output for createdb, createuser, dropdb, and
dropuser (Peter)
The --quiet option is ignored and will be removed in 8.4. Progress
messages when acting on all databases now go to stdout instead of
stderr because they are not actually errors.
__________________________________________________________________

libpq

* Interpret the dbName parameter of PQsetdbLogin() as a conninfo
string if it contains an equals sign (Andrew)
This allows use of conninfo strings in client programs that still
use PQsetdbLogin().
* Support a global SSL configuration file (Victor Wagner)
* Add environment variable PGSSLKEY to control SSL hardware keys
(Victor Wagner)
* Add lo_truncate() for large object truncation (Kris Jurka)
* Add PQconnectionNeedsPassword() that returns true if the server
required a password but none was supplied (Joe Conway, Tom)
If this returns true after a failed connection attempt, a client
application should prompt the user for a password. In the past
applications have had to check for a specific error message string
to decide whether a password is needed; that approach is now
deprecated.
* Add PQconnectionUsedPassword() that returns true if the supplied
password was actually used (Joe Conway, Tom)
This is useful in some security contexts where it is important to
know whether a user-supplied password is actually valid.
__________________________________________________________________

ecpg

* Use V3 frontend/backend protocol (Michael)
This adds support for server-side prepared statements.
* Use native threads, instead of pthreads, on Windows (Magnus)
* Improve thread-safety of ecpglib (Itagaki Takahiro)
* Make the ecpg libraries export only necessary API symbols (Michael)
__________________________________________________________________

Windows Port

* Allow the whole PostgreSQL distribution to be compiled with
Microsoft Visual C++ (Magnus and others)
This allows Windows-based developers to use familiar development
and debugging tools. Windows executables made with Visual C++ might
also have better stability and performance than those made with
other tool sets. The client-only Visual C++ build scripts have been
removed.
* Drastically reduce postmaster's memory usage when it has many child
processes (Magnus)
* Allow regression tests to be started by an administrative user
(Magnus)
* Add native shared memory implementation (Magnus)
__________________________________________________________________

Server Programming Interface (SPI)

* Add cursor-related functionality in SPI (Pavel Stehule)
Allow access to the cursor-related planning options, and add
"FETCH"/"MOVE" routines.
* Allow execution of cursor commands through SPI_execute (Tom)
The macro SPI_ERROR_CURSOR still exists but will never be returned.
* SPI plan pointers are now declared as SPIPlanPtr instead of void *
(Tom)
This does not break application code, but switching is recommended
to help catch simple programming mistakes.
__________________________________________________________________

Build Options

* Add configure option --enable-profiling to enable code profiling
(works only with gcc) (Korry Douglas and Nikhil Sontakke)
* Add configure option --with-system-tzdata to use the operating
system's time zone database (Peter)
* Fix PGXS so extensions can be built against PostgreSQL
installations whose pg_config program does not appear first in the
PATH (Tom)
* Support "gmake draft" when building the SGML documentation (Bruce)
Unless draft is used, the documentation build will now be repeated
if necessary to ensure the index is up-to-date.
__________________________________________________________________

Source Code

* Rename macro DLLIMPORT to PGDLLIMPORT to avoid conflicting with
third party includes (like Tcl) that define DLLIMPORT (Magnus)
* Create "operator families" to improve planning of queries involving
cross-data-type comparisons (Tom)
* Update GIN extractQuery() API to allow signalling that nothing can
satisfy the query (Teodor)
* Move NAMEDATALEN definition from "postgres_ext.h" to
"pg_config_manual.h" (Peter)
* Provide strlcpy() and strlcat() on all platforms, and replace
error-prone uses of strncpy(), strncat(), etc (Peter)
* Create hooks to let an external plugin monitor (or even replace)
the planner and create plans for hypothetical situations (Gurjeet
Singh, Tom)
* Create a function variable join_search_hook to let plugins override
the join search order portion of the planner (Julius Stroffek)
* Add tas() support for Renesas' M32R processor (Kazuhiro Inaoka)
* quote_identifier() and pg_dump no longer quote keywords that are
unreserved according to the grammar (Tom)
* Change the on-disk representation of the NUMERIC data type so that
the sign_dscale word comes before the weight (Tom)
* Use SYSV semaphores rather than POSIX on Darwin >= 6.0, i.e., OS X
10.2 and up (Chris Marcellino)
* Add acronym and NFS documentation sections (Bruce)
* "Postgres" is now documented as an accepted alias for "PostgreSQL"
(Peter)
* Add documentation about preventing database server spoofing when
the server is down (Bruce)
__________________________________________________________________

Contrib

* Move "contrib" "README" content into the main PostgreSQL
documentation (Albert Cervera i Areny)
* Add "contrib/pageinspect" module for low-level page inspection
(Simon, Heikki)
* Add "contrib/pg_standby" module for controlling warm standby
operation (Simon)
* Add "contrib/uuid-ossp" module for generating UUID values using the
OSSP UUID library (Peter)
Use configure --with-ossp-uuid to activate. This takes advantage of
the new UUID builtin type.
* Add "contrib/dict_int", "contrib/dict_xsyn", and
"contrib/test_parser" modules to provide sample add-on text search
dictionary templates and parsers (Sergey Karpov)
* Allow contrib/pgbench to set the fillfactor (Pavan Deolasee)
* Add timestamps to contrib/pgbench -l (Greg Smith)
* Add usage count statistics to "contrib/pgbuffercache" (Greg Smith)
* Add GIN support for "contrib/hstore" (Teodor)
* Add GIN support for "contrib/pg_trgm" (Guillaume Smet, Teodor)
* Update OS/X startup scripts in "contrib/start-scripts" (Mark
Cotner, David Fetter)
* Restrict pgrowlocks() and dblink_get_pkey() to users who have
SELECT privilege on the target table (Tom)
* Restrict "contrib/pgstattuple" functions to superusers (Tom)
* "contrib/xml2" is deprecated and planned for removal in 8.4 (Peter)
The new XML support in core PostgreSQL supersedes this module.

----
こがよういちろう


投稿者 xml-rpc : 2008年2月 5日 14:47
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