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Fix markup by using <note> for comments.

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Bruce Momjian 2003-10-30 20:49:47 +00:00
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@ -7,56 +7,84 @@
Major changes in this release:
Performance
IN/NOT IN subqueries are now much more efficient [1]
Improved GROUP BY processing by using hash buckets [2]
New multi-key hash join capability [3]
ANSI joins are now better optimized [4]
Faster and more powerful regular expression code [5]
Function-inlining for simple SQL functions [6]
IPv6
Full support for IPv6 connections and IPv6 address data types
[7]
SSL
Major improvements in SSL performance and reliability [8]
Index Growth Prevention
Allow free space map to efficiently reuse empty index pages,
and other free space management improvements. [9]
Standards Compliance
Implement information schema
Support for read-only transactions
Make cursors comply more closely with the SQL standard
New Client/Server Communication Protocol
New protocol improves connection speed/reliability, and adds
error codes, status information, a binary protocol, error
reporting verbosity, and cleaner startup packets.
Holdable Cursors
Allow cursors to exist outside transactions
Threads
libpq and ecpg are now fully thread-safe with
--enable-thread-safety [10]
Contrib
New version of full text indexing (tsearch2)
New autovacuum tool [11]
Array handling has been improved and moved into the main server
[12]
* IN/NOT IN subqueries are now much more efficient
Note: In previous releases, IN/NOT IN subqueries were joined to the
upper query by sequentially scanning the subquery looking for a
join. The 7.4 code uses the same sophisticated techniques used by
ordinary joins and so is much faster, and is now faster than EXISTS
subqueries.
* Improved GROUP BY processing by using hash buckets
Note: In previous releases, GROUP BY totals were accumulated by
sequentially scanning the list of groups looking for a match; the
7.4 code places GROUP BY values in hash buckets so the proper match
can be found much quicker. This is particularly significant in
speeding up queries that have a large number of distinct GROUP BY
values.
* New multi-key hash join capability
Note: In previous releases, hash joins could only occur on
single-column joins. This release allows multi-column hash joins.
* ANSI joins are now better optimized
Note: Prior releases evaluated ANSI join syntax only in the order
specified by the query; 7.4 allows full optimization of queries
using ANSI join syntax, meaning the optimizer considers all
possible join orderings and chooses the most efficient.
* Faster and more powerful regular expression code
Note: 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
Note: Simple SQL functions can now be inlined by including their
SQL in the main query. This improves performance by preventing
repeated calls to the SQL function --- this allows simple SQL
functions to behave like macros.
* Full support for IPv6 connections and IPv6 address data types
Note: Prior releases allowed only IPv6 connections and 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
Note: Several people very familiar with the SSL API have overhauled
our SSL code to improve SSL key negotiation and error recovery.
* Allow free space map to efficiently reuse empty index pages, and
other free space management improvements.
Note: In prior releases, index pages that were left empty because
of deleted rows could only be reused by rows with index values
similar to the original rows indexed on that page. In 7.4, VACUUM
records empty index pages and allows them to be used for any future
index rows.
* Implement information schema
* Support for read-only transactions
* Make cursors comply more closely with the SQL standard
* New protocol improves connection speed/reliability, and adds error
codes, status information, a binary protocol, error reporting
verbosity, and cleaner startup packets.
* Allow cursors to exist outside transactions, also called holdable
cursors
* libpq and ecpg are now fully thread-safe with
--enable-thread-safety
Note: While prior libpq releases already supported threads, this
release improves thread safety by fixing some non-thread-safe code
that was used in the database connection routines.
* New version of full text indexing in /contrib/tsearch2
* New autovacuum tool in /contrib
Note: This new tool 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 main server
Note: Many array limitations have been removed and they behave more
like fully-supported data types.
_________________________________________________________________
Migration to version 7.4
@ -67,16 +95,27 @@
Observe the following incompatibilities:
* The server-side autocommit setting was removed and reimplemented
in client applications and languages. [13]
in client applications and languages.
Note: 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 API's as appropriate.
* Error message wording has changed substantially in this release,
and error codes have been added.
* ANSI inner joins may behave differently because they are now
better optimized
* A number of server variables have been renamed for clarity,
primarily those related to logging
* MOVE/FETCH 0 now does nothing [14]
* MOVE/FETCH 0 now does nothing
Note: In prior releases, FETCH 0 would fetch all remaining rows,
and MOVE 0 would move to the end of the cursor.
* MOVE/FETCH now returns the actual number of rows moved/fetched, or
zero if at the beginning/end of the cursor [15]
zero if at the beginning/end of the cursor
Note: Prior releases would return the tuple count passed to the
command, not the actual number of rows FETCHed or MOVEd.
* COPY now can process carriage-return and carriage-return/line-feed
end-of-line terminated files.
* Literal carriage-returns and line-feeds are no longer accepted as
@ -85,37 +124,79 @@
VARCHAR(n) / TEXT
* FLOAT(p) now measures 'p' in bits, not digits
* Ambiguous date values now must match the ordering specified by
DateStyle [16]
DateStyle
Note: In prior releases, a date of 10/20/03 was interpreted as a
date in October even if the DateStyle specified the day should be
first. In 7.4, DateStyle is honored when converting such values and
will throw an error if the date is invalid for the current
DateStyle.
* The oidrand(), oidsrand(), and userfntest() functions have been
removed. [17]
removed.
Note: These functions were determined to be no longer useful.
* 'now' will no longer work as a column default; now() or
CURRENT_TIMESTAMP should be used instead [18]
CURRENT_TIMESTAMP should be used instead
Note: In prior releases, there was special code so the string 'now'
was 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 the now() or the
special value CURRENT_TIMESTAMP. These will work in all situations.
* 'today' will no longer work as a column default; CURRENT_DATE
should be used instead [19]
should be used instead
Note: Same description as above.
* Dollar sign ($) is no longer allowed in operator names
* Dollar sign ($) can be a non-first character in identifiers [20]
* Dollar sign ($) can be a non-first character in identifiers
Note: This was done to improve compatibility with other database
systems.
_________________________________________________________________
Changes
Server Operation Changes
Server Operation
* Allow IPv6 server connections (Nigel Kukard, Johan Jordaan, Bruce,
Tom, Kurt Roeckx, Andrew Dunstan)
* Fix SSL to handle errors cleanly (Nathan Mueller) [21]
* Fix SSL to handle errors cleanly (Nathan Mueller)
Note: In prior releases, certain rare SSL API error reports were
not handled correctly. This release fixes those problems.
gracefully.
* SSL protocol security and performance improvements (Sean
Chittenden) [22]
* Print lock information when a deadlock is detected (Tom) [23]
Chittenden)
Note: 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)
Note: This allows easier debugging of deadlock situations.
* Update "/tmp" socket mod. times regularly to avoid their removal
(Tom) [24]
(Tom)
Note: This should help prevent "/tmp" directory cleaner
administration scripts from removing server socket files.
* Enable PAM for MAC OS X (Aaron Hillegass)
* Make btree indexes fully WAL-safe (Tom) [25]
* Make btree indexes fully WAL-safe (Tom)
Note: In prior releases, under certain rare cases, a server crash
could cause btree indexes to become corrupt. This release removes
those last few rare cases.
* Allow btree index compaction and empty page reuse (Tom)
* Fix inconsistent index lookups during split of first root page
(Tom) [26]
(Tom)
Note: In prior releases, when a single-page index split into two
page, there was a brief period when another database session would
miss seeing an index entry. This failure was possible primarly on
multi-cpu machines. This release fixes that rare failure case.
* Improve free space map allocation logic (Tom)
* Preserve free space information between postmaster restarts (Tom)
[27]
Note: In prior releases, the free space map was not saved when the
postmaster was stopped, so newly started servers has no free space
information. This release saves the free space map, which is loaded
when the server is restarted.
* Set proper schema permissions in initdb (Peter)
* Add start time to pg_stat_activity (Neil)
* New code to detect corrupt disk pages; erase with
@ -131,20 +212,32 @@ Server Operation
detail (Tom)
_________________________________________________________________
Performance
Performance Changes
* Add hashing for GROUP BY aggregates (Tom)
* Allow nested loops to be smarter about multicolumn indexes (Tom)
* Allow multi-key hash joins (Tom)
* Improve constant folding (Tom)
* Add ability to inline simple SQL functions (Tom)
* Reduce memory usage for queries using complex functions (Tom) [28]
* Improve GEQO optimizer performance (Tom) [29]
* Reduce memory usage for queries using complex functions (Tom)
Note: 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)
Note: There were several inefficiencies in the way the GEQO
optimizer managed potential query paths. This release fixes this.
* 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)
* Allow the postmaster to preload libraries using preload_libraries
(Joe) [30]
(Joe)
Note: For shared libraries that require a long time to load, this
option is available so the library can be pre-loaded 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)
@ -159,52 +252,106 @@ Performance
(Henry Spencer, Tom)
* Use bit-mapped relation sets in the optimizer (Tom)
* Improve backend startup time (Tom)
Note: The new network 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) [31]
* Improve hash index concurrency and speed (Tom)
Note: 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
btree and hash index performance.
* Align shared buffers on 32-byte boundary for copy speed
improvement (Manfred Spraul) [32]
improvement (Manfred Spraul)
Note: Certain CPU's perform faster data copies when addresses are
32-bit aligned.
* The NUMERIC datatype has been reimplemented for better performance
(Tom) [33]
(Tom)
Note: NUMERIC used to be stored in base-100. The new code uses
base-10000, for significantly better performance.
_________________________________________________________________
Server Configuration
Server Configuration Changes
* Rename server parameter server_min_messages to log_min_messages
(Bruce) [34]
(Bruce)
Note: This was done so most parameters that control the server logs
being 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)
Note: 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-super
users (Bruce)
Note: This is a security feature so non-super-users can't disable
logging that was enabled by the administrator.
* log_min_messages/client_min_messages now controls debug_* output
(Bruce)
* Add Rendezvous server support (Chris Campbell)
Note: This centralizes client debug information so all debug output
can be sent to either the client or server logs.
* Add OS X Rendezvous server support (Chris Campbell)
Note: This allows OS X machines to query the network for available
PostgreSQL servers.
* Add ability to print only slow statements using
log_min_duration_statement (Christopher)
Note: 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)
Note: This allows administrators to merge the host IP address and
netmask fields into a single CIDR field in pg_hba.conf.
* New is_superuser read-only variable (Tom)
* New server-side parameter log_error_verbosity to control error
detail (Tom)
Note: 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)
Note: This option is useful for administration tools that need to
know the configuration variable names and their minimum, maximums,
defaults, and descriptions.
* Make default shared_buffers 1000 and max_connections 100, if
possible (Tom)
Note: Prior versions defaulted to 64 shared buffers so PostgreSQL
would start on even old computers. This release tests the amount of
shared memory supported by the hardware and sizes it accordingly.
Of course, users are still encouraged to evaluate their resource
load and size shared_buffers accordingly.
* Add new columns in pg_settings: context, type, source, min_val,
max_val (Joe)
* New pg_hba.conf 'hostnossl' to prevent SSL connections (Jon
Jensen)
Note: 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 geqo_random_seed server parameter (Tom)
_________________________________________________________________
Queries
Query Changes
* New SQL-standard information schema (Peter)
* Add read-only transactions (Peter)
* Add server variable regex_flavor to control regular expression
@ -222,8 +369,8 @@ Queries
* Change EXECUTE INTO to CREATE TABLE AS EXECUTE (Peter)
_________________________________________________________________
Object Manipulation
Object Manipulation Changes
* Make CREATE SEQUENCE grammar more SQL1999 standards compliant
(Neil)
* Add FOR EACH STATEMENT statement-level triggers (Neil)
@ -245,8 +392,8 @@ Object Manipulation
* Add WITH GRANT OPTION clause to GRANT, per SQL spec (Peter)
_________________________________________________________________
Utility Commands
Utility Command Changes
* Add ON COMMIT clause to CREATE TABLE for temp tables (Gavin)
* Allow cursors outside transactions using WITH HOLD (Neil)
* MOVE/FETCH 0 now does nothing (Bruce)
@ -302,8 +449,8 @@ Utility Commands
* Long options for pg_dump are now available on all platforms
_________________________________________________________________
Data Types and Functions
Data Type and Function Changes
* New extra_float_digits server parameter to control float precision
display (Pedro Ferreira, Tom)
* Allow +1300 as a numeric timezone specifier, for FJST (Tom)
@ -369,8 +516,8 @@ Data Types and Functions
* Allow time to be specified as '040506' or '0405' (Tom)
_________________________________________________________________
Server-side Languages
Server-side Language Changes
* Prevent PL/pgSQL crash when RETURN NEXT is used on a zero-row
record var. (Tom)
* Make PL/python's spi_execute interface handle NULLs properly
@ -391,8 +538,8 @@ Server-side Languages
the parameter type list (Jan)
_________________________________________________________________
Psql
Psql Changes
* Add "\pset pager always" to always use pager (Greg)
* Improve tab completion (Rod, Ross Reedstrom, Ian Barwick)
* Reorder \? help into groupings (Harald Armin Massa, Bruce)
@ -409,8 +556,8 @@ Psql
* Long options for psql are now available on all platforms
_________________________________________________________________
Libpq
Libpq Changes
* Allow PQcmdTuples() to return row counts for MOVE and FETCH (Neil)
* Add PQfreemem() for freeing memory on Win32, suggest for NOTIFY
(Bruce)
@ -433,8 +580,8 @@ Libpq
perform Bind/Execute of previously prepared statements (Tom)
_________________________________________________________________
JDBC
JDBC Changes
* Allow setNull on updateable resultsets
* Allow executeBatch on a prepared statement (Barry)
* Support SSL connections (Barry)
@ -442,8 +589,8 @@ JDBC
* Add refcursor support (Nic Ferrier)
_________________________________________________________________
Miscellaneous Interfaces
Miscellaneous Interface Changes
* Prevent possible memory leak or core dump during libpgtcl shutdown
(Tom)
* Add ecpg Informix compatibility (Michael)
@ -453,8 +600,8 @@ Miscellaneous Interfaces
* Move python client interface to http://www.pygresql.org (Marc)
_________________________________________________________________
Source Code
Source Code Changes
* Prevent need for separate platform geometry regression result
files (Tom)
* Improved PPC locking primitive (Reinhard Max)
@ -481,8 +628,8 @@ Source Code
* Generate a compile error if spinlock code is not found (Bruce)
_________________________________________________________________
Contrib
Contrib Changes
* Change dbmirror license to BSD
* Improve earthdistance (Bruno Wolff III)
* Portability improvements to pgcrypto (Marko Kreen)
@ -510,8 +657,8 @@ Contrib
* Remove array module because features now included by default (Joe)
_________________________________________________________________
Other Uncategorized
Other Uncategorized Changes
* "DATESTYLE" can now be set to DMY, YMD, or MDY to specify input
field order
* Input date order must now be YYYY-MM-DD (with 4-digit year) or
@ -4709,171 +4856,3 @@ The following bugs have been fixed in postgres95-beta-0.02:
Release date: 1995-05-01
Initial release.
Notes
[1]
In previous releases, IN/NOT IN subqueries were joined to the upper
query by sequentially scanning the subquery looking for a join. The
7.4 code uses the same sophisticated techniques used by ordinary joins
and so is much faster, and is now faster than EXISTS subqueries.
[2]
In previous releases, GROUP BY totals were accumulated by sequentially
scanning the list of groups looking for a match; the 7.4 code places
GROUP BY values in hash buckets so the proper match can be found much
quicker. This is particularly significant in speeding up queries that
have a large number of distinct GROUP BY values.
[3]
In previous releases, hash joins could only occur on single-column
joins. This release allows multi-column hash joins.
[4]
Prior releases evaluated ANSI join syntax only in the order specified
by the query; 7.4 allows full optimization of queries using ANSI join
syntax, meaning the optimizer considers all possible join orderings
and chooses the most efficient.
[5]
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.
[6]
Simple SQL functions can now be inlined by including their SQL in the
main query. This improves performance by preventing repeated calls to
the SQL function --- this allows simple SQL functions to behave like
macros.
[7]
Prior releases allowed only IPv6 connections and IP data types only
supported IPv4 addresses. This release adds full IPv6 support in both
of these areas.
[8]
Several people very familiar with the SSL API have overhauled our SSL
code to improve SSL key negotiation and error recovery.
[9]
In prior releases, index pages that were left empty because of deleted
rows could only be reused by rows with index values similar to the
original rows indexed on that page. In 7.4, VACUUM records empty index
pages and allows them to be used for any future index rows.
[10]
While prior libpq releases already supported threads, this release
improves thread safety by fixing some non-thread-safe code that was
used in the database connection routines.
[11]
This new tool monitors the database statistics tables for
INSERT/UPDATE/DELETE activity and automatically vacuums tables when
needed.
[12]
Many array limitations have been removed and they behave more like
fully-supported data types.
[13]
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 API's as appropriate.
[14]
In prior releases, FETCH 0 would fetch all remaining rows, and MOVE 0
would move to the end of the cursor.
[15]
Prior releases would return the tuple count passed to the command, not
the actual number of rows FETCHed or MOVEd.
[16]
In prior releases, a date of 10/20/03 was interpreted as a date in
October even if the DateStyle specified the day should be first. In
7.4, DateStyle is honored when converting such values and will throw
an error if the date is invalid for the current DateStyle.
[17]
These functions were determined to be no longer useful.
[18]
In prior releases, there was special code so the string 'now' was
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 the now() or the special value
CURRENT_TIMESTAMP. These will work in all situations.
[19]
Same description as above.
[20]
This was done to improve compatibility with other database systems.
[21]
In prior releases, certain rare SSL API error reports were not handled
correctly. This release fixes those problems. gracefully.
[22]
SSL key renegotiation was happening too frequently, causing poor SSL
performance. Also, initial key handling was improved.
[23]
This allows easier debugging of deadlock situations.
[24]
This should help prevent "/tmp" directory cleaner administration
scripts from removing server socket files.
[25]
In prior releases, under certain rare cases, a server crash could
cause btree indexes to become corrupt. This release removes those last
few rare cases.
[26]
In prior releases, when a single-page index split into two page, there
was a brief period when another database session would miss seeing an
index entry. This failure was possible primarly on multi-cpu machines.
This release fixes that rare failure case.
[27]
In prior releases, the free space map was not saved when the
postmaster was stopped, so newly started servers has no free space
information. This release saves the free space map, which is loaded
when the server is restarted.
[28]
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.
[29]
There were several inefficiencies in the way the GEQO optimizer
managed potential query paths. This release fixes this.
[30]
For shared libraries that require a long time to load, this option is
available so the library can be pre-loaded in the postmaster and
inherited by all database sessions.
[31]
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 btree and hash
index performance.
[32]
Certain CPU's perform faster data copies when addresses are 32-bit
aligned.
[33]
NUMERIC used to be stored in base-100. The new code uses base-10000,
for significantly better performance.
[34]
This was done so most parameters that control the server logs being
with log_.

226
doc/src/sgml/release.sgml
View File

@ -1,5 +1,5 @@
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/release.sgml,v 1.226 2003/10/30 20:31:24 momjian Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/release.sgml,v 1.227 2003/10/30 20:49:47 momjian Exp $
-->
<appendix id="release">
@ -14,7 +14,7 @@ $Header: /cvsroot/pgsql/doc/src/sgml/release.sgml,v 1.226 2003/10/30 20:31:24 mo
<itemizedlist>
<listitem><para> IN/NOT IN subqueries are now much more efficient</para>
<sect3>
<note>
<para>
In previous releases, IN/NOT IN subqueries were joined to the
upper query by sequentially scanning the subquery looking for
@ -22,11 +22,11 @@ $Header: /cvsroot/pgsql/doc/src/sgml/release.sgml,v 1.226 2003/10/30 20:31:24 mo
used by ordinary joins and so is much faster, and is now faster
than EXISTS subqueries.
</para>
</sect3>
</note>
</listitem>
<listitem><para> Improved GROUP BY processing by using hash buckets</para>
<sect3>
<note>
<para>
In previous releases, GROUP BY totals were accumulated by
sequentially scanning the list of groups looking for a match;
@ -35,76 +35,76 @@ $Header: /cvsroot/pgsql/doc/src/sgml/release.sgml,v 1.226 2003/10/30 20:31:24 mo
significant in speeding up queries that have a large
number of distinct GROUP BY values.
</para>
</sect3>
</note>
</listitem>
<listitem><para> New multi-key hash join capability</para>
<sect3>
<note>
<para>
In previous releases, hash joins could only occur on single-column
joins. This release allows multi-column hash joins.
</para>
</sect3>
</note>
</listitem>
<listitem><para> ANSI joins are now better optimized</para>
<sect3>
<note>
<para>
Prior releases evaluated ANSI join syntax only in the order
specified by the query; 7.4 allows full optimization of
queries using ANSI join syntax, meaning the optimizer considers
all possible join orderings and chooses the most efficient.
</para>
</sect3>
</note>
</listitem>
<listitem><para> Faster and more powerful regular expression code
</para>
<sect3>
<note>
<para>
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.
</para>
</sect3>
</note>
</listitem>
<listitem><para> Function-inlining for simple SQL functions</para>
<sect3>
<note>
<para>
Simple SQL functions can now be inlined by including their SQL
in the main query. This improves performance by preventing
repeated calls to the SQL function --- this allows simple
SQL functions to behave like macros.
</para>
</sect3>
</note>
</listitem>
<listitem><para> Full support for IPv6 connections and IPv6 address
data types</para>
<sect3>
<note>
<para>
Prior releases allowed only IPv6 connections and IP data types only
supported IPv4 addresses. This release adds full IPv6 support in
both of these areas.
</para>
</sect3>
</note>
</listitem>
<listitem><para> Major improvements in SSL performance and
reliability</para>
<sect3>
<note>
<para>
Several people very familiar with the SSL API have overhauled our
SSL code to improve SSL key negotiation and error recovery.
</para>
</sect3>
</note>
</listitem>
<listitem><para> Allow free space map to efficiently reuse empty index
pages, and other free space management improvements.</para>
<sect3>
<note>
<para>
In prior releases, index pages that were left empty because of
deleted rows could only be reused by rows with index values similar
@ -112,7 +112,7 @@ pages, and other free space management improvements.</para>
empty index pages and allows them to be used for any future index
rows.
</para>
</sect3>
</note>
</listitem>
<listitem><para>Implement information schema</para>
@ -122,51 +122,51 @@ pages, and other free space management improvements.</para>
</listitem>
<listitem><para>Make cursors comply more closely with the SQL standard
</para></glossdef>
</para>
</listitem>
<listitem><para> New protocol improves connection speed/reliability,
and adds error codes, status information, a binary protocol, error
reporting verbosity, and cleaner startup packets.</para></glossdef>
reporting verbosity, and cleaner startup packets.</para>
</listitem>
<listitem><glossdef><para> Allow cursors to exist outside transactions,
<listitem><para> Allow cursors to exist outside transactions,
also called holdable cursors
</para>
</listitem>
<listitem><glossdef><para> libpq and ecpg are now fully thread-safe with
<listitem><para> libpq and ecpg are now fully thread-safe with
--enable-thread-safety</para>
<sect3>
<note>
<para>
While prior libpq releases already supported threads, this release
improves thread safety by fixing some non-thread-safe code that
was used in the database connection routines.
</para>
</sect3>
</para>
</note>
</listitem>
<listitem><para> New version of full text indexing in /contrib/tsearch2</para>
</listitem>
<listitem><para> New autovacuum tool in /contrib</para>
<sect3>
<note>
<para>
This new tool monitors the database statistics tables for
INSERT/UPDATE/DELETE activity and automatically vacuums tables when
needed.
</para>
</sect3>
</note>
</listitem>
<listitem><para> Array handling has been improved and moved into the main
server</para>
<sect3>
<note>
<para>
Many array limitations have been removed and they behave more like
fully-supported data types.
</para>
</sect3>
</note>
</listitem>
</itemizedlist></para></sect2>
@ -179,14 +179,14 @@ required for those wishing to migrate data from any previous release.</para>
<itemizedlist>
<listitem><para> The server-side autocommit setting was removed and reimplemented
in client applications and languages.</para>
<sect3>
<para>
<note>
<para>
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 API's as appropriate.
</para>
</sect3>
</para>
</note>
</listitem>
<listitem><para> Error message wording has changed substantially in this release,
and error codes have been added.</para></listitem>
@ -194,21 +194,21 @@ required for those wishing to migrate data from any previous release.</para>
<listitem><para> A number of server variables have been renamed for
clarity, primarily those related to logging</para></listitem>
<listitem><para> MOVE/FETCH 0 now does nothing</para>
<sect3>
<para>
<note>
<para>
In prior releases, FETCH 0 would fetch all remaining rows, and
MOVE 0 would move to the end of the cursor.
</para>
</sect3>
</para>
</note>
</listitem>
<listitem><para> MOVE/FETCH now returns the actual number of rows moved/fetched, or zero
if at the beginning/end of the cursor</para>
<sect3>
<para>
<note>
<para>
Prior releases would return the tuple count passed to the
command, not the actual number of rows FETCHed or MOVEd.
</para>
</sect3>
</para>
</note>
</listitem>
<listitem><para> COPY now can process carriage-return and
carriage-return/line-feed end-of-line terminated files.</para></listitem>
@ -219,29 +219,29 @@ required for those wishing to migrate data from any previous release.</para>
<type>VARCHAR(n)</type> / <type>TEXT</type></para></listitem>
<listitem><para> <function>FLOAT(p)</function> now measures 'p' in bits, not digits</para></listitem>
<listitem><para> Ambiguous date values now must match the ordering specified by DateStyle</para>
<sect3>
<para>
<note>
<para>
In prior releases, a date of <literal>10/20/03</> was
interpreted as a date in October even if the
<varname>DateStyle</> specified the day should be first. In
7.4, <varname>DateStyle</> is honored when converting such
values and will throw an error if the date is invalid for the
current <varname>DateStyle</>.
</para>
</sect3>
</para>
</note>
</listitem>
<listitem><para> The <function>oidrand()</function>, <function>oidsrand()</function>,
and <function>userfntest()</function> functions have been removed.</para>
<sect3>
<para>
<note>
<para>
These functions were determined to be no longer useful.
</para>
</sect3>
</para>
</note>
</listitem>
<listitem><para> <literal>'now'</literal> will no longer work as a column default; <function>now()</> or
<function>CURRENT_TIMESTAMP</> should be used instead</para>
<sect3>
<para>
<note>
<para>
In prior releases, there was special code so the string
<literal>'now'</literal> was interpreted at
<command>INSERT</> time and not at table creation time, but
@ -250,25 +250,25 @@ required for those wishing to migrate data from any previous release.</para>
<function>now()</> or the special value
<function>CURRENT_TIMESTAMP</>. These will work in all
situations.
</para>
</sect3>
</para>
</note>
</listitem>
<listitem><para> <literal>'today'</literal> will no longer work as a column default; <function>CURRENT_DATE</>
should be used instead</para>
<sect3>
<para>
<note>
<para>
Same description as above.
</para>
</sect3>
</para>
</note>
</listitem>
<listitem><para> Dollar sign (<literal>$</>) is no longer allowed in operator names</para></listitem>
<listitem><para> Dollar sign (<literal>$</>) can be a non-first character in identifiers</para>
<sect3>
<para>
<note>
<para>
This was done to improve compatibility with other database
systems.
</para>
</sect3>
</para>
</note>
</listitem>
</itemizedlist></para></sect2>
@ -277,68 +277,68 @@ required for those wishing to migrate data from any previous release.</para>
<listitem><para>Allow IPv6 server connections (Nigel Kukard, Johan Jordaan, Bruce, Tom, Kurt
Roeckx, Andrew Dunstan)</para></listitem>
<listitem><para>Fix SSL to handle errors cleanly (Nathan Mueller)
<sect3>
<note>
<para>
In prior releases, certain rare SSL API error reports were not
handled correctly. This release fixes those problems.
gracefully.
</para>
</sect3>
</note>
</para></listitem>
<listitem><para>SSL protocol security and performance improvements (Sean Chittenden)</para>
<sect3>
<note>
<para>
SSL key renegotiation was happening too frequently, causing poor SSL
performance. Also, initial key handling was improved.
</para>
</sect3>
</note>
</listitem>
<listitem><para>Print lock information when a deadlock is detected (Tom)</para>
<sect3>
<note>
<para>
This allows easier debugging of deadlock situations.
</para>
</sect3>
</note>
</listitem>
<listitem><para>Update <filename>/tmp</filename> socket mod. times regularly to avoid their removal (Tom)</para>
<sect3>
<note>
<para>
This should help prevent <filename>/tmp</filename> directory cleaner
administration scripts from removing server socket files.
</para>
</sect3>
</note>
</listitem>
<listitem><para>Enable PAM for MAC OS X (Aaron Hillegass)</para></listitem>
<listitem><para>Make btree indexes fully WAL-safe (Tom)</para>
<sect3>
<note>
<para>
In prior releases, under certain rare cases, a server crash could
cause btree indexes to become corrupt. This release removes those
last few rare cases.
</para>
</sect3>
</note>
</listitem>
<listitem><para>Allow btree index compaction and empty page reuse (Tom)</para></listitem>
<listitem><para>Fix inconsistent index lookups during split of first root page (Tom)</para>
<sect3>
<note>
<para>
In prior releases, when a single-page index split into two page,
there was a brief period when another database session would miss
seeing an index entry. This failure was possible primarly on
multi-cpu machines. This release fixes that rare failure case.
</para>
</sect3>
</note>
</listitem>
<listitem><para>Improve free space map allocation logic (Tom)</para></listitem>
<listitem><para>Preserve free space information between postmaster restarts (Tom)</para>
<sect3>
<note>
<para>
In prior releases, the free space map was not saved when the
postmaster was stopped, so newly started servers has no free space
information. This release saves the free space map, which is loaded
when the server is restarted.
</para>
</sect3>
</note>
</listitem>
<listitem><para>Set proper schema permissions in initdb (Peter)</para></listitem>
<listitem><para>Add start time to pg_stat_activity (Neil)</para></listitem>
@ -361,34 +361,34 @@ required for those wishing to migrate data from any previous release.</para>
<listitem><para>Improve constant folding (Tom)</para></listitem>
<listitem><para>Add ability to inline simple SQL functions (Tom)</para></listitem>
<listitem><para>Reduce memory usage for queries using complex functions (Tom)</para>
<sect3>
<note>
<para>
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.
</para>
</sect3>
</note>
</listitem>
<listitem><para>Improve GEQO optimizer performance (Tom)</para>
<sect3>
<note>
<para>
There were several inefficiencies in the way the GEQO optimizer
managed potential query paths. This release fixes this.
</para>
</sect3>
</note>
</listitem>
<listitem><para>Allow IN/NOT IN to be handled via hash tables (Tom)</para></listitem>
<listitem><para>Improve NOT IN (subquery) performance (Tom)</para></listitem>
<listitem><para>Allow most IN subqueries to be processed as joins (Tom)</para></listitem>
<listitem><para>Allow the postmaster to preload libraries using preload_libraries (Joe)</para>
<sect3>
<note>
<para>
For shared libraries that require a long time to load, this option
is available so the library can be pre-loaded in the postmaster and
inherited by all database sessions.
</para>
</sect3>
</note>
</listitem>
<listitem><para>Improve optimizer cost computations, particularly for subqueries (Tom)</para></listitem>
<listitem><para>Avoid sort when subquery ORDER BY matches upper query (Tom)</para></listitem>
@ -400,41 +400,41 @@ required for those wishing to migrate data from any previous release.</para>
<listitem><para>Use faster and more powerful regular expression code from TCL (Henry Spencer, Tom)</para></listitem>
<listitem><para>Use bit-mapped relation sets in the optimizer (Tom)</para></listitem>
<listitem><para>Improve backend startup time (Tom)</para>
<sect3>
<note>
<para>
The new network protocol requires fewer network packets to start a
database session.
</para>
</sect3>
</note>
</listitem>
<listitem><para>Improve trigger/constraint performance (Stephan)</para></listitem>
<listitem><para>Improve speed of col IN (const, const, const, ...) (Tom)</para></listitem>
<listitem><para>Fix hash indexes which were broken in rare cases (Tom)</para></listitem>
<listitem><para>Improve hash index concurrency and speed (Tom)</para>
<sect3>
<note>
<para>
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
btree and hash index performance.
</para>
</sect3>
</note>
</listitem>
<listitem><para>Align shared buffers on 32-byte boundary for copy speed improvement (Manfred Spraul)</para>
<sect3>
<note>
<para>
Certain CPU's perform faster data copies when addresses are 32-bit
aligned.
</para>
</sect3>
</note>
</listitem>
<listitem><para>The NUMERIC datatype has been reimplemented for better performance (Tom)</para>
<sect3>
<note>
<para>
NUMERIC used to be stored in base-100. The new code uses base-10000,
for significantly better performance.
</para>
</sect3>
</note>
</listitem>
</itemizedlist></sect2>
@ -442,88 +442,88 @@ required for those wishing to migrate data from any previous release.</para>
<itemizedlist>
<listitem><para>Rename server parameter server_min_messages to log_min_messages (Bruce)</para>
<sect3>
<note>
<para>
This was done so most parameters that control the server logs being
with <literal>log_</>.
</para>
</sect3>
</note>
</listitem>
<listitem><para>Rename show_*_stats to log_*_stats (Bruce)</para></listitem>
<listitem><para>Rename show_source_port to log_source_port (Bruce)</para></listitem>
<listitem><para>Rename hostname_lookup to log_hostname (Bruce)</para></listitem>
<listitem><para>Add checkpoint_warning to warn of excessive checkpointing (Bruce)</para>
<sect3>
<note>
<para>
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.
</para>
</sect3>
</note>
</listitem>
<listitem><para>New read-only server parameters for localization (Tom)</para></listitem>
<listitem><para>Change debug server log messages to output as DEBUG rather than LOG (Bruce)</para></listitem>
<listitem><para>Prevent server log variables from being turned off by non-super users (Bruce)</para>
<sect3>
<note>
<para>
This is a security feature so non-super-users can't disable logging
that was enabled by the administrator.
</para>
</sect3>
</note>
</listitem>
<listitem><para>log_min_messages/client_min_messages now controls debug_* output (Bruce)</para>
<sect3>
<note>
<para>
This centralizes client debug information so all debug output can
be sent to either the client or server logs.
</para>
</sect3>
</note>
</listitem>
<listitem><para>Add OS X Rendezvous server support (Chris Campbell)</para>
<sect3>
<note>
<para>
This allows OS X machines to query the network for available
PostgreSQL servers.
</para>
</sect3>
</note>
</listitem>
<listitem><para>Add ability to print only slow statements using log_min_duration_statement
(Christopher)</para>
<sect3>
<note>
<para>
This is an often requested debugging feature that allows administrators to
see only slow queries in their server logs.</para>
see only slow queries in their server logs.
</para>
</sect3>
</note>
</listitem>
<listitem><para>Allow pg_hba.conf to accept netmasks in CIDR format (Andrew Dunstan)</para>
<sect3>
<note>
<para>
This allows administrators to merge the host IP address and netmask
fields into a single CIDR field in pg_hba.conf.
</para>
</sect3>
</note>
</listitem>
<listitem><para>New is_superuser read-only variable (Tom)</para></listitem>
<listitem><para>New server-side parameter log_error_verbosity to control error detail (Tom)</para>
<sect3>
<note>
<para>
This works with the new error reporting feature to supply additional
error information like hints, file names and line numbers.
</para>
</sect3>
</note>
</listitem>
<listitem><para>postgres --describe-config now dumps server config variables (Aizaz Ahmed, Peter)</para>
<sect3>
<note>
<para>
This option is useful for administration tools that need to know the
configuration variable names and their minimum, maximums, defaults,
and descriptions.
</para>
</sect3>
</note>
</listitem>
<listitem><para>Make default shared_buffers 1000 and max_connections 100, if possible (Tom)</para>
<sect3>
<note>
<para>
Prior versions defaulted to 64 shared buffers so PostgreSQL would
start on even old computers. This release tests the amount of shared
@ -531,17 +531,17 @@ required for those wishing to migrate data from any previous release.</para>
course, users are still encouraged to evaluate their resource load
and size shared_buffers accordingly.
</para>
</sect3>
</note>
</listitem>
<listitem><para>Add new columns in pg_settings: context, type, source, min_val, max_val (Joe)</para></listitem>
<listitem><para>New pg_hba.conf 'hostnossl' to prevent SSL connections (Jon Jensen)
<sect3>
<note>
<para>
In prior releases, there was no way to prevent SSL connections if
both the client and server supported SSL. This option allows that
capability.
</para>
</sect3>
</note>
</listitem>
<listitem><para>Remove geqo_random_seed server parameter (Tom)</para></listitem>
</itemizedlist></sect2>