Release Notes
Release 7.4
Release date: 2003-11-17
_________________________________________________________________
Overview
Major changes in this release:
IN/NOT IN subqueries are now much more efficient
In previous releases, IN/NOT IN subqueries were joined to the
upper query by sequentially scanning the subquery looking for a
match. The 7.4 code uses the same sophisticated techniques used
by ordinary joins and so is much faster. An IN will now usually
be as fast as or faster than an equivalent EXISTS subquery;
this reverses the conventional wisdom that applied to previous
releases.
Improved GROUP BY processing by using hash buckets
In previous releases, rows to be grouped had to be sorted
first. The 7.4 code can do GROUP BY without sorting, by
accumulating results into a hash table with one entry per
group. It will still use the sort technique, however, if the
hash table is estimated to be too large to fit in sort_mem.
New multikey hash join capability
In previous releases, hash joins could only occur on single
keys. This release allows multicolumn hash joins.
Queries using the explicit JOIN syntax are now better optimized
Prior releases evaluated queries using the explicit JOIN syntax
only in the order implied by the syntax. 7.4 allows full
optimization of these queries, meaning the optimizer considers
all possible join orderings and chooses the most efficient.
Outer joins, however, must still follow the declared ordering.
Faster and more powerful regular expression code
The entire regular expression module has been replaced with a
new version by Henry Spencer, originally written for Tcl. The
code greatly improves performance and supports several flavors
of regular expressions.
Function-inlining for simple SQL functions
Simple SQL functions can now be inlined by including their SQL
in the main query. This improves performance by eliminating
per-call overhead. That means simple SQL functions now behave
like macros.
Full support for IPv6 connections and IPv6 address data types
Previous releases allowed only IPv4 connections, and the IP
data types only supported IPv4 addresses. This release adds
full IPv6 support in both of these areas.
Major improvements in SSL performance and reliability
Several people very familiar with the SSL API have overhauled
our SSL code to improve SSL key negotiation and error recovery.
Make free space map efficiently reuse empty index pages, and other
free space management improvements
In previous releases, B-tree index pages that were left empty
because of deleted rows could only be reused by rows with index
values similar to the rows originally indexed on that page. In
7.4, "VACUUM" records empty index pages and allows them to be
reused for any future index rows.
SQL-standard information schema
The information schema provides a standardized and stable way
to access information about the schema objects defined in a
database.
Cursors conform more closely to the SQL standard
The commands "FETCH" and "MOVE" have been overhauled to conform
more closely to the SQL standard.
Cursors can exist outside transactions
These cursors are also called holdable cursors.
New client-to-server protocol
The new protocol adds error codes, more status information,
faster startup, better support for binary data transmission,
parameter values separated from SQL commands, prepared
statements available at the protocol level, and cleaner
recovery from "COPY" failures. The older protocol is still
supported by both server and clients.
libpq and ECPG applications are now fully thread-safe
While previous libpq releases already supported threads, this
release improves thread safety by fixing some non-thread-safe
code that was used during database connection startup. The
"configure" option "--enable-thread-safety" must be used to
enable this feature.
New version of full-text indexing
A new full-text indexing suite is available in
"contrib/tsearch2".
New autovacuum tool
The new autovacuum tool in "contrib/autovacuum" monitors the
database statistics tables for "INSERT"/"UPDATE"/"DELETE"
activity and automatically vacuums tables when needed.
Array handling has been improved and moved into the server core
Many array limitations have been removed, and arrays behave
more like fully-supported data types.
_________________________________________________________________
Migration to version 7.4
A dump/restore using pg_dump is required for those wishing to migrate
data from any previous release.
Observe the following incompatibilities:
* The server-side autocommit setting was removed and reimplemented
in client applications and languages. Server-side autocommit was
causing too many problems with languages and applications that
wanted to control their own autocommit behavior, so autocommit was
removed from the server and added to individual client APIs as
appropriate.
* Error message wording has changed substantially in this release.
Significant effort was invested to make the messages more
consistent and user-oriented. If your applications try to detect
different error conditions by parsing the error message, you are
strongly encouraged to use the new error code facility instead.
* Inner joins using the explicit JOIN syntax may behave differently
because they are now better optimized.
* A number of server configuration parameters have been renamed for
clarity, primarily those related to logging.
* FETCH 0 or MOVE 0 now does nothing. In prior releases, FETCH 0
would fetch all remaining rows, and MOVE 0 would move to the end
of the cursor.
* "FETCH" and "MOVE" now return the actual number of rows
fetched/moved, or zero if at the beginning/end of the cursor.
Prior releases would return the row count passed to the command,
not the number of rows actually fetched or moved.
* "COPY" now can process files that use carriage-return or
carriage-return/line-feed end-of-line sequences. Literal
carriage-returns and line-feeds are no longer accepted in data
values; use \r and \n instead.
* Trailing spaces are now trimmed when converting from type char(n)
to varchar(n) or text. This is what most people always expected to
happen anyway.
* The data type float(p) now measures "p" in binary digits, not
decimal digits. The new behavior follows the SQL standard.
* Ambiguous date values now must match the ordering specified by the
datestyle setting. In prior releases, a date specification of
10/20/03 was interpreted as a date in October even if datestyle
specified that the day should be first. 7.4 will throw an error if
a date specification is invalid for the current setting of
datestyle.
* The functions oidrand, oidsrand, and userfntest have been removed.
These functions were determined to be no longer useful.
* String literals specifying time-varying date/time values, such as
'now' or 'today' will no longer work as expected in column default
expressions; they now cause the time of the table creation to be
the default, not the time of the insertion. Functions such as
now(), current_timestamp, or current_date should be used instead.
In previous releases, there was special code so that strings such
as 'now' were interpreted at "INSERT" time and not at table
creation time, but this work around didn't cover all cases.
Release 7.4 now requires that defaults be defined properly using
functions such as now() or current_timestamp. These will work in
all situations.
* The dollar sign ($) is no longer allowed in operator names. It can
instead be a non-first character in identifiers. This was done to
improve compatibility with other database systems, and to avoid
syntax problems when parameter placeholders ($n) are written
adjacent to operators.
_________________________________________________________________
Changes
Below you will find a detailed account of the changes between release
7.4 and the previous major release.
_________________________________________________________________
Server Operation Changes
* Allow IPv6 server connections (Nigel Kukard, Johan Jordaan, Bruce,
Tom, Kurt Roeckx, Andrew Dunstan)
* Fix SSL to handle errors cleanly (Nathan Mueller)
In prior releases, certain SSL API error reports were not handled
correctly. This release fixes those problems.
* SSL protocol security and performance improvements (Sean
Chittenden)
SSL key renegotiation was happening too frequently, causing poor
SSL performance. Also, initial key handling was improved.
* Print lock information when a deadlock is detected (Tom)
This allows easier debugging of deadlock situations.
* Update "/tmp" socket modification times regularly to avoid their
removal (Tom)
This should help prevent "/tmp" directory cleaner administration
scripts from removing server socket files.
* Enable PAM for Mac OS X (Aaron Hillegass)
* Make B-tree indexes fully WAL-safe (Tom)
In prior releases, under certain rare cases, a server crash could
cause B-tree indexes to become corrupt. This release removes those
last few rare cases.
* Allow B-tree index compaction and empty page reuse (Tom)
* Fix inconsistent index lookups during split of first root page
(Tom)
In prior releases, when a single-page index split into two pages,
there was a brief period when another database session could miss
seeing an index entry. This release fixes that rare failure case.
* Improve free space map allocation logic (Tom)
* Preserve free space information between server restarts (Tom)
In prior releases, the free space map was not saved when the
postmaster was stopped, so newly started servers had no free space
information. This release saves the free space map, and reloads it
when the server is restarted.
* Add start time to pg_stat_activity (Neil)
* New code to detect corrupt disk pages; erase with
zero_damaged_pages (Tom)
* New client/server protocol: faster, no username length limit,
allow clean exit from "COPY" (Tom)
* Add transaction status, table ID, column ID to client/server
protocol (Tom)
* Add binary I/O to client/server protocol (Tom)
* Remove autocommit server setting; move to client applications
(Tom)
* New error message wording, error codes, and three levels of error
detail (Tom, Joe, Peter)
_________________________________________________________________
Performance Improvements
* Add hashing for GROUP BY aggregates (Tom)
* Make nested-loop joins be smarter about multicolumn indexes (Tom)
* Allow multikey hash joins (Tom)
* Improve constant folding (Tom)
* Add ability to inline simple SQL functions (Tom)
* Reduce memory usage for queries using complex functions (Tom)
In prior releases, functions returning allocated memory would not
free it until the query completed. This release allows the freeing
of function-allocated memory when the function call completes,
reducing the total memory used by functions.
* Improve GEQO optimizer performance (Tom)
This release fixes several inefficiencies in the way the GEQO
optimizer manages potential query paths.
* Allow IN/NOT IN to be handled via hash tables (Tom)
* Improve NOT IN (subquery) performance (Tom)
* Allow most IN subqueries to be processed as joins (Tom)
* Pattern matching operations can use indexes regardless of locale
(Peter)
There is no way for non-ASCII locales to use the standard indexes
for LIKE comparisons. This release adds a way to create a special
index for LIKE.
* Allow the postmaster to preload libraries using preload_libraries
(Joe)
For shared libraries that require a long time to load, this option
is available so the library can be preloaded in the postmaster and
inherited by all database sessions.
* Improve optimizer cost computations, particularly for subqueries
(Tom)
* Avoid sort when subquery ORDER BY matches upper query (Tom)
* Deduce that WHERE a.x = b.y AND b.y = 42 also means a.x = 42 (Tom)
* Allow hash/merge joins on complex joins (Tom)
* Allow hash joins for more data types (Tom)
* Allow join optimization of explicit inner joins, disable with
join_collapse_limit (Tom)
* Add parameter from_collapse_limit to control conversion of
subqueries to joins (Tom)
* Use faster and more powerful regular expression code from Tcl
(Henry Spencer, Tom)
* Use bit-mapped relation sets in the optimizer (Tom)
* Improve connection startup time (Tom)
The new client/server protocol requires fewer network packets to
start a database session.
* Improve trigger/constraint performance (Stephan)
* Improve speed of col IN (const, const, const, ...) (Tom)
* Fix hash indexes which were broken in rare cases (Tom)
* Improve hash index concurrency and speed (Tom)
Prior releases suffered from poor hash index performance,
particularly for high concurrency situations. This release fixes
that, and the development group is interested in reports comparing
B-tree and hash index performance.
* Align shared buffers on 32-byte boundary for copy speed
improvement (Manfred Spraul)
Certain CPU's perform faster data copies when addresses are
32-byte aligned.
* Data type numeric reimplemented for better performance (Tom)
numeric used to be stored in base 100. The new code uses base
10000, for significantly better performance.
_________________________________________________________________
Server Configuration Changes
* Rename server parameter server_min_messages to log_min_messages
(Bruce)
This was done so most parameters that control the server logs
begin with log_.
* Rename show_*_stats to log_*_stats (Bruce)
* Rename show_source_port to log_source_port (Bruce)
* Rename hostname_lookup to log_hostname (Bruce)
* Add checkpoint_warning to warn of excessive checkpointing (Bruce)
In prior releases, it was difficult to determine if checkpoint was
happening too frequently. This feature adds a warning to the
server logs when excessive checkpointing happens.
* New read-only server parameters for localization (Tom)
* Change debug server log messages to output as DEBUG rather than
LOG (Bruce)
* Prevent server log variables from being turned off by
non-superusers (Bruce)
This is a security feature so non-superusers cannot disable
logging that was enabled by the administrator.
* log_min_messages/client_min_messages now controls debug_* output
(Bruce)
This centralizes client debug information so all debug output can
be sent to either the client or server logs.
* Add Mac OS X Rendezvous server support (Chris Campbell)
This allows Mac OS X hosts to query the network for available
PostgreSQL servers.
* Add ability to print only slow statements using
log_min_duration_statement (Christopher)
This is an often requested debugging feature that allows
administrators to see only slow queries in their server logs.
* Allow "pg_hba.conf" to accept netmasks in CIDR format (Andrew
Dunstan)
This allows administrators to merge the host IP address and
netmask fields into a single CIDR field in "pg_hba.conf".
* New read-only parameter is_superuser (Tom)
* New parameter log_error_verbosity to control error detail (Tom)
This works with the new error reporting feature to supply
additional error information like hints, file names and line
numbers.
* postgres --describe-config now dumps server config variables
(Aizaz Ahmed, Peter)
This option is useful for administration tools that need to know
the configuration variable names and their minimums, maximums,
defaults, and descriptions.
* Add new columns in pg_settings: context, type, source, min_val,
max_val (Joe)
* Make default shared_buffers 1000 and max_connections 100, if
possible (Tom)
Prior versions defaulted to 64 shared buffers so PostgreSQL would
start on even very old systems. This release tests the amount of
shared memory allowed by the platform and selects more reasonable
default values if possible. Of course, users are still encouraged
to evaluate their resource load and size shared_buffers
accordingly.
* New "pg_hba.conf" record type hostnossl to prevent SSL connections
(Jon Jensen)
In prior releases, there was no way to prevent SSL connections if
both the client and server supported SSL. This option allows that
capability.
* Remove parameter geqo_random_seed (Tom)
* Add server parameter regex_flavor to control regular expression
processing (Tom)
* Make "pg_ctl" better handle nonstandard ports (Greg)
_________________________________________________________________
Query Changes
* New SQL-standard information schema (Peter)
* Add read-only transactions (Peter)
* Print key name and value in foreign-key violation messages (Dmitry
Tkach)
* Allow users to see their own queries in pg_stat_activity (Kevin
Brown)
In prior releases, only the superuser could see query strings
using pg_stat_activity. Now ordinary users can see their own query
strings.
* Fix aggregates in subqueries to match SQL standard (Tom)
The SQL standard says that an aggregate function appearing within
a nested subquery belongs to the outer query if its argument
contains only outer-query variables. Prior PostgreSQL releases did
not handle this fine point correctly.
* Add option to prevent auto-addition of tables referenced in query
(Nigel J. Andrews)
By default, tables mentioned in the query are automatically added
to the FROM clause if they are not already there. This is
compatible with historic POSTGRES behavior but is contrary to the
SQL standard. This option allows selecting standard-compatible
behavior.
* Allow UPDATE ... SET col = DEFAULT (Rod)
This allows "UPDATE" to set a column to its declared default
value.
* Allow expressions to be used in LIMIT/OFFSET (Tom)
In prior releases, LIMIT/OFFSET could only use constants, not
expressions.
* Implement CREATE TABLE AS EXECUTE (Neil, Peter)
_________________________________________________________________
Object Manipulation Changes
* Make "CREATE SEQUENCE" grammar more conforming to SQL 2003 (Neil)
* Add statement-level triggers (Neil)
While this allows a trigger to fire at the end of a statement, it
does not allow the trigger to access all rows modified by the
statement. This capability is planned for a future release.
* Add check constraints for domains (Rod)
This greatly increases the usefulness of domains by allowing them
to use check constraints.
* Add "ALTER DOMAIN" (Rod)
This allows manipulation of existing domains.
* Fix several zero-column table bugs (Tom)
PostgreSQL supports zero-column tables. This fixes various bugs
that occur when using such tables.
* Have ALTER TABLE ... ADD PRIMARY KEY add not-null constraint (Rod)
In prior releases, ALTER TABLE ... ADD PRIMARY would add a unique
index, but not a not-null constraint. That is fixed in this
release.
* Add ALTER TABLE ... WITHOUT OIDS (Rod)
This allows control over whether new and updated rows will have an
OID column. This is most useful for saving storage space.
* Add ALTER SEQUENCE to modify minimum, maximum, increment, cache,
cycle values (Rod)
* Add ALTER TABLE ... CLUSTER ON (Alvaro Herrera)
This command is used by "pg_dump" to record the cluster column for
each table previously clustered. This information is used by
database-wide cluster to cluster all previously clustered tables.
* Improve automatic type casting for domains (Rod, Tom)
* Allow dollar signs in identifiers, except as first character (Tom)
* Disallow dollar signs in operator names, so x=$1 works (Tom)
* Allow copying table schema using LIKE subtable, also SQL 2003
feature INCLUDING DEFAULTS (Rod)
* Add WITH GRANT OPTION clause to "GRANT" (Peter)
This enabled "GRANT" to give other users the ability to grant
privileges on a object.
_________________________________________________________________
Utility Command Changes
* Add ON COMMIT clause to "CREATE TABLE" for temporary tables
(Gavin)
This adds the ability for a table to be dropped or all rows
deleted on transaction commit.
* Allow cursors outside transactions using WITH HOLD (Neil)
In previous releases, cursors were removed at the end of the
transaction that created them. Cursors can now be created with the
WITH HOLD option, which allows them to continue to be accessed
after the creating transaction has committed.
* FETCH 0 and MOVE 0 now do nothing (Bruce)
In previous releases, FETCH 0 fetched all remaining rows, and MOVE
0 moved to the end of the cursor.
* Cause "FETCH" and "MOVE" to return the number of rows
fetched/moved, or zero if at the beginning/end of cursor, per SQL
standard (Bruce)
In prior releases, the row count returned by "FETCH" and "MOVE"
did not accurately reflect the number of rows processed.
* Properly handle SCROLL with cursors, or report an error (Neil)
Allowing random access (both forward and backward scrolling) to
some kinds of queries cannot be done without some additional work.
If SCROLL is specified when the cursor is created, this additional
work will be performed. Furthermore, if the cursor has been
created with NO SCROLL, no random access is allowed.
* Implement SQL-compatible options FIRST, LAST, ABSOLUTE n, RELATIVE
n for "FETCH" and "MOVE" (Tom)
* Allow "EXPLAIN" on "DECLARE CURSOR" (Tom)
* Allow "CLUSTER" to use index marked as pre-clustered by default
(Alvaro Herrera)
* Allow "CLUSTER" to cluster all tables (Alvaro Herrera)
This allows all previously clustered tables in a database to be
reclustered with a single command.
* Prevent "CLUSTER" on partial indexes (Tom)
* Allow DOS and Mac line-endings in "COPY" files (Bruce)
* Disallow literal carriage return as a data value,
backslash-carriage-return and \r are still allowed (Bruce)
* "COPY" changes (binary, \.) (Tom)
* Recover from "COPY" failure cleanly (Tom)
* Prevent possible memory leaks in "COPY" (Tom)
* Make "TRUNCATE" transaction-safe (Rod)
"TRUNCATE" can now be used inside a transaction. If the
transaction aborts, the changes made by the "TRUNCATE" are
automatically rolled back.
* Allow prepare/bind of utility commands like "FETCH" and "EXPLAIN"
(Tom)
* Add "EXPLAIN EXECUTE" (Neil)
* Improve "VACUUM" performance on indexes by reducing WAL traffic
(Tom)
* Functional indexes have been generalized into indexes on
expressions (Tom)
In prior releases, functional indexes only supported a simple
function applied to one or more column names. This release allows
any type of scalar expression.
* Have "SHOW TRANSACTION ISOLATION" match input to "SET TRANSACTION
ISOLATION" (Tom)
* Have "COMMENT ON DATABASE" on nonlocal database generate a warning
(Rod)
Database comments are stored in database-local tables so comments
on a database have to be stored in each database.
* Improve reliability of "LISTEN"/"NOTIFY" (Tom)
* Allow "REINDEX" to reliably reindex nonshared system catalog
indexes (Tom)
This allows system tables to be reindexed without the requirement
of a standalone session, which was necessary in previous releases.
The only tables that now require a standalone session for
reindexing are the global system tables pg_database, pg_shadow,
and pg_group.
_________________________________________________________________
Data Type and Function Changes
* New server parameter extra_float_digits to control precision
display of floating-point numbers (Pedro Ferreira, Tom)
This controls output precision which was causing regression
testing problems.
* Allow +1300 as a numeric time-zone specifier, for FJST (Tom)
* Remove rarely used functions oidrand, oidsrand, and userfntest
functions (Neil)
* Add md5() function to main server, already in "contrib/pgcrypto"
(Joe)
An MD5 function was frequently requested. For more complex
encryption capabilities, use "contrib/pgcrypto".
* Increase date range of timestamp (John Cochran)
* Change EXTRACT(EPOCH FROM timestamp) so timestamp without time
zone is assumed to be in local time, not GMT (Tom)
* Trap division by zero in case the operating system doesn't prevent
it (Tom)
* Change the numeric data type internally to base 10000 (Tom)
* New hostmask() function (Greg Wickham)
* Fixes for to_char() and to_timestamp() (Karel)
* Allow functions that can take any argument data type and return
any data type, using anyelement and anyarray (Joe)
This allows the creation of functions that can work with any data
type.
* Arrays may now be specified as ARRAY[1,2,3],
ARRAY[['a','b'],['c','d']], or ARRAY[ARRAY[ARRAY[2]]] (Joe)
* Allow proper comparisons for arrays, including ORDER BY and
DISTINCT support (Joe)
* Allow indexes on array columns (Joe)
* Allow array concatenation with || (Joe)
* Allow WHERE qualification expr op ANY/SOME/ALL (array_expr) (Joe)
This allows arrays to behave like a list of values, for purposes
like SELECT * FROM tab WHERE col IN (array_val).
* New array functions array_append, array_cat, array_lower,
array_prepend, array_to_string, array_upper, string_to_array (Joe)
* Allow user defined aggregates to use polymorphic functions (Joe)
* Allow assignments to empty arrays (Joe)
* Allow 60 in seconds fields of time, timestamp, and interval input
values (Tom)
Sixty-second values are needed for leap seconds.
* Allow cidr data type to be cast to text (Tom)
* Disallow invalid time zone names (Tom)
* Trim trailing spaces when char is cast to varchar or text (Tom)
* Make float(p) measure the precision "p" in binary digits, not
decimal digits (Tom)
* Add IPv6 support to the inet and cidr data types (Michael Graff)
* Add family() function to report whether address is IPv4 or IPv6
(Michael Graff)
* Have SHOW datestyle generate output similar to that used by SET
datestyle (Tom)
* Make EXTRACT(TIMEZONE) and SET/SHOW TIME ZONE follow the SQL
convention for the sign of time zone offsets, i.e., positive is
east from UTC (Tom)
* Fix date_trunc('quarter', ...) (Böjthe Zoltán)
Prior releases returned an incorrect value for this function call.
* Make initcap() more compatible with Oracle (Mike Nolan)
initcap() now uppercases a letter appearing after any
non-alphanumeric character, rather than only after whitespace.
* Allow only datestyle field order for date values not in ISO-8601
format (Greg)
* Add new datestyle values MDY, DMY, and YMD to set input field
order; honor US and European for backward compatibility (Tom)
* String literals like 'now' or 'today' will no longer work as a
column default. Use functions such as now(), current_timestamp
instead. (change required for prepared statements) (Tom)
* Treat NaN as larger than any other value in min()/max() (Tom)
NaN was already sorted after ordinary numeric values for most
purposes, but min() and max() didn't get this right.
* Prevent interval from suppressing :00 seconds display
* New function pg_get_triggerdef(prettyprint) and
pg_constraint_is_visible()
* Allow time to be specified as 040506 or 0405 (Tom)
* Input date order must now be YYYY-MM-DD (with 4-digit year) or
match datestyle
* Make pg_get_constraintdef to support unique, primary-key, and
check constraints (Christopher)
_________________________________________________________________
Server-Side Language Changes
* Prevent PL/pgSQL crash when RETURN NEXT is used on a zero-row
record variable (Tom)
* Make PL/Python's spi_execute interface handle null values properly
(Andrew Bosma)
* Allow PL/pgSQL to declare variables of composite types without
%ROWTYPE (Tom)
* Fix PL/Python's _quote() function to handle big integers
* Make PL/Python an untrusted language, now called plpythonu (Kevin
Jacobs, Tom)
The Python language no longer supports a restricted execution
environment, so the trusted version of PL/Python was removed. If
this situation changes, a version of PL/python that can be used by
non-superusers will be readded.
* Allow polymorphic PL/pgSQL functions (Tom, Joe)
* Allow polymorphic SQL functions (Joe)
* Improved compiled function caching mechanism in PL/pgSQL with full
support for polymorphism (Joe)
* Add new parameter $0 in PL/pgSQL representing the function's
actual return type (Joe)
* Allow PL/Tcl and PL/Python to use the same trigger on multiple
tables (Tom)
* Fixed PL/Tcl's spi_prepare to accept fully qualified type names in
the parameter type list (Jan)
_________________________________________________________________
psql Changes
* Add \pset pager always to always use pager (Greg)
This forces the pager to be used even if the number of rows is
less than the screen height. This is valuable for rows that wrap
across several screen rows.
* Improve tab completion (Rod, Ross Reedstrom, Ian Barwick)
* Reorder \? help into groupings (Harald Armin Massa, Bruce)
* Add backslash commands for listing schemas, casts, and conversions
(Christopher)
* "\encoding" now changes based on the server parameter
client_encoding server (Tom)
In previous versions, "\encoding" was not aware of encoding
changes made using SET client_encoding.
* Save editor buffer into readline history (Ross)
When "\e" is used to edit a query, the result is saved in the
readline history for retrieval using the up arrow.
* Improve "\d" display (Christopher)
* Enhance HTML mode to be more standards-conforming (Greg)
* New "\set AUTOCOMMIT off" capability (Tom)
This takes the place of the removed server parameter autocommit.
* New "\set VERBOSITY" to control error detail (Tom)
This controls the new error reporting details.
* New prompt escape sequence %x to show transaction status (Tom)
* Long options for psql are now available on all platforms
_________________________________________________________________
pg_dump Changes
* Multiple pg_dump fixes, including tar format and large objects
* Allow pg_dump to dump specific schemas (Neil)
* Make pg_dump preserve column storage characteristics (Christopher)
This preserves ALTER TABLE ... SET STORAGE information.
* Make pg_dump preserve "CLUSTER" characteristics (Christopher)
* Have pg_dumpall use "GRANT"/"REVOKE" to dump database-level
privleges (Tom)
* Allow pg_dumpall to support the options "-a", "-s", "-x" of
pg_dump (Tom)
* Prevent pg_dump from lowercasing identifiers specified on the
command line (Tom)
* pg_dump options "--use-set-session-authorization" and
"--no-reconnect" now do nothing, all dumps use "SET SESSION
AUTHORIZATION"
pg_dump no longer reconnects to switch users, but instead always
uses "SET SESSION AUTHORIZATION". This will reduce password
prompting during restores.
* Long options for pg_dump are now available on all platforms
PostgreSQL now includes its own long-option processing routines.
_________________________________________________________________
libpq Changes
* Add function PQfreemem for freeing memory on Windows, suggested
for "NOTIFY" (Bruce)
Windows requires that memory allocated in a library be freed by a
function in the same library, hence free() doesn't work for
freeing memory allocated by libpq. PQfreemem is the proper way to
free libpq memory, especially on Windows, and is recommended for
other platforms as well.
* Document service capability, and add sample file (Bruce)
This allows clients to look up connection information in a central
file on the client machine.
* Make PQsetdbLogin have the same defaults as PQconnectdb (Tom)
* Allow libpq to cleanly fail when result sets are too large (Tom)
* Improve performance of function PGunescapeBytea (Ben Lamb)
* Allow thread-safe libpq with "configure" option
"--enable-thread-safety" (Lee Kindness, Philip Yarra)
* Allow function pqInternalNotice to accept a format string and
arguments instead of just a preformatted message (Tom, Sean
Chittenden)
* Control SSL negotiation with sslmode values disable, allow,
prefer, and require (Jon Jensen)
* Allow new error codes and levels of text (Tom)
* Allow access to the underlying table and column of a query result
(Tom)
This is helpful for query-builder applications that want to know
the underlying table and column names associated with a specific
result set.
* Allow access to the current transaction status (Tom)
* Add ability to pass binary data directly to the server (Tom)
* Add function PQexecPrepared and PQsendQueryPrepared functions
which perform bind/execute of previously prepared statements (Tom)
_________________________________________________________________
JDBC Changes
* Allow setNull on updateable result sets
* Allow executeBatch on a prepared statement (Barry)
* Support SSL connections (Barry)
* Handle schema names in result sets (Paul Sorenson)
* Add refcursor support (Nic Ferrier)
_________________________________________________________________
Miscellaneous Interface Changes
* Prevent possible memory leak or core dump during libpgtcl shutdown
(Tom)
* Add Informix compatibility to ECPG (Michael)
This allows ECPG to process embedded C programs that were written
using certain Informix extensions.
* Add type decimal to ECPG that is fixed length, for Informix
(Michael)
* Allow thread-safe embedded SQL programs with "configure" option
"--enable-thread-safety" (Lee Kindness, Bruce)
This allows multiple threads to access the database at the same
time.
* Moved Python client PyGreSQL to http://www.pygresql.org (Marc)
_________________________________________________________________
Source Code Changes
* Prevent need for separate platform geometry regression result
files (Tom)
* Improved PPC locking primitive (Reinhard Max)
* New function palloc0 to allocate and clear memory (Bruce)
* Fix locking code for s390x CPU (64-bit) (Tom)
* Allow OpenBSD to use local ident credentials (William Ahern)
* Make query plan trees read-only to executor (Tom)
* Add Darwin startup scripts (David Wheeler)
* Allow libpq to compile with Borland C++ compiler (Lester Godwin,
Karl Waclawek)
* Use our own version of getopt_long() if needed (Peter)
* Convert administration scripts to C (Peter)
* Bison >= 1.85 is now required to build the PostgreSQL grammar, if
building from CVS
* Merge documentation into one book (Peter)
* Add Windows compatibility functions (Bruce)
* Allow client interfaces to compile under MinGW (Bruce)
* New ereport() function for error reporting (Tom)
* Support Intel compiler on Linux (Peter)
* Improve Linux startup scripts (Slawomir Sudnik, Darko Prenosil)
* Add support for AMD Opteron and Itanium (Jeffrey W. Baker, Bruce)
* Remove "--enable-recode" option from "configure"
This was no longer needed now that we have "CREATE CONVERSION".
* Generate a compile error if spinlock code is not found (Bruce)
Platforms without spinlock code will now fail to compile, rather
than silently using semaphores. This failure can be disabled with
a new "configure" option.
_________________________________________________________________
Contrib Changes
* Change dbmirror license to BSD
* Improve earthdistance (Bruno Wolff III)
* Portability improvements to pgcrypto (Marko Kreen)
* Prevent crash in xml (John Gray, Michael Richards)
* Update oracle
* Update mysql
* Update cube (Bruno Wolff III)
* Update earthdistance to use cube (Bruno Wolff III)
* Update btree_gist (Oleg)
* New tsearch2 full-text search module (Oleg, Teodor)
* Add hash-based crosstab function to tablefuncs (Joe)
* Add serial column to order connectby() siblings in tablefuncs
(Nabil Sayegh,Joe)
* Add named persistent connections to dblink (Shridhar Daithanka)
* New pg_autovacuum allows automatic "VACUUM" (Matthew T. O'Connor)
* Make pgbench honor environment variables PGHOST, PGPORT, PGUSER
(Tatsuo)
* Improve intarray (Teodor Sigaev)
* Improve pgstattuple (Rod)
* Fix bug in metaphone() in fuzzystrmatch
* Improve adddepend (Rod)
* Update spi/timetravel (Böjthe Zoltán)
* Fix dbase "-s" option and improve non-ASCII handling (Thomas Behr,
Márcio Smiderle)
* Remove array module because features now included by default (Joe)