Release date: 2008-02-04
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 NULL
s 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.
A dump/restore using pg_dump is required for those wishing to migrate data from any previous release.
Observe the following incompatibilities:
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(
and n
)varchar(
still cast to n
)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)
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.
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.
Below you will find a detailed account of the changes between PostgreSQL 8.3 and the previous major release.
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 database or 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
, using
asynchronous commit does not put database consistency at risk; the
worst case is that after a crash the last few reportedly-committed
transactions might not be committed after all. 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
automatically 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 232 (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)
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_
(Tom)nnn
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.
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)
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)
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.
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 NULL
s 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)
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.
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
(Holger Schurig)table
USING index
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 ?column
for complicated
cases.N
?
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.
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)
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.
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)
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.
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)
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)
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.
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.
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)
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)
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.
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.
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., macOS 10.2 and up (Chris Marcellino)
"Postgres" is now documented as an accepted alias for "PostgreSQL" (Peter)
Add documentation about preventing database server spoofing when the server is down (Bruce)
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.
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