<!--
-$PostgreSQL: pgsql/doc/src/sgml/release.sgml,v 1.365 2005/09/04 13:40:24 alvherre Exp $
+$PostgreSQL: pgsql/doc/src/sgml/release.sgml,v 1.366 2005/09/11 23:40:33 neilc Exp $
Typical markup:
[A-Za-z_]/[A-Za-z_]+ <filename>
PostgreSQL <productname>
pg_[A-Za-z0-9_] <application>
-[A-Z][A-Z] <type>, <envar.
- <literal>
+[A-Z][A-Z] <type>, <envar>, <literal>
&<> use &
-->
<listitem>
<para>
- This was accomplished by eliminating global locks and using a
- clock sweep algorithm to find free buffers. This increases
- scalability on multi-CPU systems.
- </para>
+ Access to the shared buffer cache was identified as a
+ significant scalability problem, particularly on multi-CPU
+ systems. In this release, the way that locking is done in the
+ buffer manager has been overhauled to reduce lock contention
+ and improve scalability. The buffer manager has also been
+ changed to use a <quote>clock sweep</quote> replacement
+ policy.
+ </para>
</listitem>
</varlistentry>
<para>
In previous releases, only a single index could be used to do
lookups on a table. With this feature, if a query has
- <command>WHERE tab.col1 = 4 and tab.col2 = 9</>, and there is no
- multicolumn index on col1 and col2, but there is an index on
- col1 and another on col2, it is possible to search both indexes
- and combine the results in memory, then do heap fetches for only
- the rows matching both the col1 and col2
- restrictions. This is very useful in environments that have a
- lot of unstructured queries where it is impossible to create
- indexes that match all possible access conditions. Bitmap scans
- are useful even with a single index, as they reduce the amount
- of random access needed; a bitmap index scan is efficient for
- retrieving fairly large fractions of the complete table, whereas
- plain index scans are not.
+ <command>WHERE tab.col1 = 4 and tab.col2 = 9</>, and there is
+ no multicolumn index on <literal>col1</> and <literal>col2</>,
+ but there is an index on <literal>col1</> and another on
+ <literal>col2</>, it is possible to search both indexes and
+ combine the results in memory, then do heap fetches for only
+ the rows matching both the <literal>col1</> and
+ <literal>col2</> restrictions. This is very useful in
+ environments that have a lot of unstructured queries where it
+ is impossible to create indexes that match all possible access
+ conditions. Bitmap scans are useful even with a single index,
+ as they reduce the amount of random access needed; a bitmap
+ index scan is efficient for retrieving fairly large fractions
+ of the complete table, whereas plain index scans are not.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
Move <filename>/contrib/pg_autovacuum</> into the main server
- (Alvaro Herrera)
+ (Alvaro)
</term>
<listitem>
</sect2>
<sect2>
- <title>Migration to version 8.1</title>
+ <title>Migration to 8.1</title>
<para>
A dump/restore using <application>pg_dump</application> is required
<varname>default_with_oids</> is now false by default (Neil)
</para>
<para>
- With this option set to false, user-created tables no longer have
- the usually-invisible OID column unless <command>WITH OIDS</>
- is specified in <command>CREATE TABLE</>. Though OIDs have
- existed in all releases of
- <productname>PostgreSQL</productname>, their use is limited
+ With this option set to false, user-created tables no longer
+ have an OID column unless <command>WITH OIDS</> is specified in
+ <command>CREATE TABLE</>. Though OIDs have existed in all
+ releases of <productname>PostgreSQL</>, their use is limited
because they are only four bytes long and the counter is shared
across all installed databases. The preferred way of uniquely
- identifying rows is via sequences and <command>SERIAL</>, which
- have been supported since <productname>PostgreSQL</productname>
- 6.4.
+ identifying rows is via sequences and the <type>SERIAL</> type,
+ which have been supported since <productname>PostgreSQL</> 6.4.
</para>
</listitem>
syntax is formed by writing an <literal>E</> immediately preceding the
single quote that starts the string, e.g. <literal>E'hi\n'</>. While
this release does not change the handling of backslashes in strings, it
- does add new GUC variables to help users migrate applications
+ does add new configuration parameters to help users migrate applications
for future releases:
</para>
<itemizedlist>
<listitem>
<para>
- <varname>standard_conforming_strings</> - does this release
+ <varname>standard_conforming_strings</> — does this release
treat backslashes literally in ordinary strings?
</para>
</listitem>
<listitem>
<para>
- <varname>escape_string_warning</> - warn about backslashes in
+ <varname>escape_string_warning</> — warn about backslashes in
ordinary (non-E) strings
</para>
</listitem>
The <varname>standard_conforming_strings</> value is read-only.
Applications can retrieve the value to know how backslashes are
processed. (Presence of the parameter can also be taken as an
- indication that <literal>E''</> string syntax is supported.) In a
- future release, <varname>standard_conforming_strings</> will be true,
- meaning backslashes will be treated literally in non-E strings. To
- prepare for this change, use <literal>E''</> strings in places that
- need special backslash processing, and turn on
- <varname>escape_string_warning</> to find additional strings that need
- to be converted to use <literal>E''</>. Also, use two single-quotes
- (<literal>''</>) to embed a literal single-quote in a string, rather
- than the PostgreSQL-supported syntax of backslash single-quote
- (<literal>\'</>). The former is standards-conforming and does not
- require the use of the <literal>E''</> string syntax. You can also use
- the <literal>$$</> string syntax, which does not treat backslashes
+ indication that <literal>E''</> string syntax is supported.)
+ In a future release, <varname>standard_conforming_strings</>
+ will be true, meaning backslashes will be treated literally in
+ non-E strings. To prepare for this change, use <literal>E''</>
+ strings in places that need special backslash processing, and
+ turn on <varname>escape_string_warning</> to find additional
+ strings that need to be converted to use <literal>E''</>.
+ Also, use two single-quotes (<literal>''</>) to embed a literal
+ single-quote in a string, rather than the
+ <productname>PostgreSQL</productname>-supported syntax of
+ backslash single-quote (<literal>\'</>). The former is
+ standards-conforming and does not require the use of the
+ <literal>E''</> string syntax. You can also use the
+ <literal>$$</> string syntax, which does not treat backslashes
specially.
</para>
</listitem>
<listitem>
<para>
- In psql, treat unquoted <literal>\{digit}+</> sequences as octal
- (Bruce)
+ In <application>psql</application>, treat unquoted
+ <literal>\{digit}+</> sequences as octal (Bruce)
</para>
<para>
In previous releases, <literal>\{digit}+</> sequences were
<title>Additional Changes</title>
<para>
- Below you will find a detailed account of the additional changes
- between release 8.1 and the previous major release.
+ Below you will find a detailed account of the additional changes
+ between <productname>PostgreSQL</productname> 8.1 and the
+ previous major release.
</para>
<sect3>
<listitem>
<para>
- Improve rtree index capabilities and performance (Neil)
+ Improve GiST and rtree index performance (Neil)
</para>
</listitem>
<listitem>
<para>
Allow non-consecutive index columns to be used in a multi-column
- index
- (Tom)
+ index (Tom)
</para>
<para>
For example, this allows an index on columns a,b,c to be used in
<listitem>
<para>
- Add GUC <varname>full_page_writes</> to control writing full
- pages to WAL
- (Bruce)
+ Add configuration parameter <varname>full_page_writes</> to
+ control writing full pages to WAL (Bruce)
</para>
<para>
To prevent partial disk writes from corrupting the database,
<listitem>
<para>
- Add constraint_exclusion to restrict child table lookups based
- on table constraints (Simon)
+ Add <varname>constraint_exclusion</varname> configuration
+ parameter to restrict child table lookups based on table
+ constraints (Simon)
</para>
<para>
This allows for a type of table partitioning. If child tables
<listitem>
<para>
Use <literal>O_DIRECT</> if available when using
- <literal>O_SYNC</> for wal_sync_method (Itagaki Takahiro)
+ <literal>O_SYNC</> for <varname>wal_sync_method</varname>
+ (Itagaki Takahiro)
</para>
<para>
<literal>O_DIRECT</> causes disk writes to bypass the kernel
</itemizedlist>
</sect3>
-
-
+
<sect3>
<title>Server Changes</title>
<itemizedlist>
-
+
<listitem>
<para>
Prevent problems due to transaction ID (XID) wraparound (Tom)
<listitem>
<para>
- Add <varname>temp_buffers</> GUC variable to allow users to
- determine the size of the local buffer area for temporary table
- access (Tom)
+ Add <varname>temp_buffers</> configuration parameter to allow
+ users to determine the size of the local buffer area for
+ temporary table access (Tom)
</para>
</listitem>
<listitem>
<para>
- Add GUC <varname>krb_server_hostname</> so the server hostname
- can be specified as part of service principal (Todd Kover)
+ Add configuration parameter <varname>krb_server_hostname</> so
+ that the server hostname can be specified as part of service
+ principal (Todd Kover)
</para>
<para>
If not set, any service principal matching an entry in the
Add WAL logging for GIST indexes (Teodor, Oleg)
</para>
<para>
- GIST indexes are now safe for crash and point-in-time recovery
+ GIST indexes are now safe for crash and point-in-time recovery.
</para>
</listitem>
<listitem>
<para>
- Add GUC variables to control TCP/IP keep-alive times for idle,
- interval, and count (Oliver Jowett)
+ Add configuration parameters to control TCP/IP keep-alive
+ times for idle, interval, and count (Oliver Jowett)
</para>
<para>
<listitem>
<para>
- Allow more than two gigabyes of shared memory and per-backend
+ Allow more than two gigabytes of shared memory and per-backend
work memory on 64-bit machines (Koichi Suzuki)
</para>
</listitem>
<listitem>
<para>
- Add temporary views (Koju Iijima)
+ Add temporary views (Koju Iijima, Neil)
</para>
</listitem>
<listitem>
<para>
Add <command>USING</> clause to allow additional tables to be
- specified to <command>DELETE</> (Euler Taveira de Oliveira)
+ specified to <command>DELETE</> (Euler Taveira de Oliveira, Neil)
</para>
<para>
In prior releases, there was no clear method for specifying
additional tables to be used for joins in a <command>DELETE</>
- statement. <command>UPDATE</> already has a <command>FROM</>
+ statement. <command>UPDATE</> already has a <literal>FROM</>
clause for this purpose.
</para>
</listitem>
UPDATE/SHARE</> (Hans-Juergen Schoenig)
</para>
<para>
- While <command>SET</> <varname>statement_timeout</> allows a query
- taking over a certain amount of time to be cancelled, the
- <command>NOWAIT</> option allows a query to be canceled as soon as a
- <command>SELECT ... FOR UPDATE/SHARE</> command cannot immediately
- acquire a row lock.
+ While the <varname>statement_timeout</> configuration
+ parameter allows a query taking more than a certain amount of
+ time to be cancelled, the <command>NOWAIT</> option allows a
+ query to be canceled as soon as a <command>SELECT ... FOR
+ UPDATE/SHARE</> command cannot immediately acquire a row lock.
</para>
</listitem>
-
</itemizedlist>
</sect3>
<listitem>
<para>
- Add ALTER TABLE ENABLE/DISABLE TRIGGER to disable triggers
- (Satoshi Nagayasu)
+ Add <command>ALTER TABLE ENABLE/DISABLE TRIGGER</command> to
+ disable triggers (Satoshi Nagayasu)
</para>
</listitem>
<listitem>
<para>
Properly process carriage returns and line feeds in
- <command>COPY CSV</> mode (Andrew Dunstan)
+ <command>COPY CSV</> mode (Andrew)
</para>
<para>
In release 8.0, carriage returns and line feeds in <command>CSV
<listitem>
<para>
- Make initdb create a new standard database called
- <literal>postgres</>, and convert utilities to use
- <literal>postgres</> rather than <literal>template1</> for
+ Make <application>initdb</application> create a new standard
+ database called <literal>postgres</>, and convert utilities to
+ use <literal>postgres</> rather than <literal>template1</> for
standard lookups (Dave)
</para>
<para>
- In prior releases, <literal>template1</> was used both as a default
- connection for utilities like createuser, and as a template for
+ In prior releases, <literal>template1</> was used both as a
+ default connection for utilities like
+ <application>createuser</application>, and as a template for
new databases. This caused <command>CREATE DATABASE</> to
sometimes fail, because a new database cannot be created if
anyone else is in the template database. With this change, the
- default connection database is now <literal>postgres</>, meaning
- it is much less likely someone will be using
+ default connection database is now <literal>postgres</>,
+ meaning it is much less likely someone will be using
<literal>template1</> during <command>CREATE DATABASE</>.
</para>
</listitem>
<listitem>
<para>
- Create new reindexdb command-line utility by moving
- <filename>/contrib/reindexdb</> into the server (Euler Taveira
- de Oliveira)
+ Create new <application>reindexdb</application> command-line
+ utility by moving <filename>/contrib/reindexdb</> into the
+ server (Euler Taveira de Oliveira)
</para>
</listitem>
<listitem>
<para>
- Add <function>GREATEST()</> and <function>LEAST()</> functions
- (Pavel Stehule)
+ Add <function>GREATEST()</> and <function>LEAST()</> variadic
+ functions (Pavel Stehule)
</para>
<para>
These functions take a variable number of arguments and return
</para>
</listitem>
-
<listitem>
<para>
Add <function>pg_rotate_logfile()</> to force rotation of the
</itemizedlist>
</para>
+
<para>
The original names still work.
</para>
<listitem>
<para>
Allow direct conversion between <literal>EUC_JP</> and
- <literal>SJIS</> to improve performance (Atsushi
- Ogawa)
+ <literal>SJIS</> to improve performance (Atsushi Ogawa)
</para>
</listitem>
Reduce memory usage of PL/PgSQL functions (Neil)
</para>
<para>
- Each function now has its own memory context that can be freed
- when the function exits.
+ The parsetree of each function is now stored in a separate
+ memory context. This allows the memory to be easily reclaimed
+ when it is no longer needed.
</para>
</listitem>
rather than at runtime (Neil)
</para>
<para>
- Previously, syntax errors were reported only when the function
- was executed.
+ Previously, most syntax errors were reported only when the
+ function was executed.
</para>
</listitem>
<listitem>
<para>
Add support for an optional <command>INTO</> clause to
- PL/PgSQL's <command>EXECUTE</> command (Pavel Stehule)
+ PL/PgSQL's <command>EXECUTE</> command (Pavel Stehule, Neil)
</para>
</listitem>
<para>
Define <literal>SQLSTATE</> and <literal>SQLERRM</> to return
the <literal>SQLSTATE</> and error message of the current
- exception (Pavel Stehule)
+ exception (Pavel Stehule, Neil)
</para>
<para>
These variables are only accessible inside exception blocks.
<listitem>
<para>
Allow the parameters to the <command>RAISE</> statement to be
- expressions (Pavel Stehule)
+ expressions (Pavel Stehule, Neil)
</para>
</listitem>
<listitem>
<para>
- Add a loop <command>CONTINUE</> statement (Pavel Stehule)
+ Add a loop <command>CONTINUE</> statement (Pavel Stehule, Neil)
</para>
</listitem>
<listitem>
<para>
- Allow one-row-at-a-time retrieval of query results (Abhijit)
+ Allow one-row-at-a-time retrieval of query results (Abhijit Menon-Sen)
</para>
<para>
This allows functions to use <function>spi_query()</> and
<listitem>
<para>
- Allow <literal>strict</> mode to be enabled (Andrew)
+ Allow Perl's <literal>strict</> mode to be enabled (Andrew)
</para>
</listitem>
</itemizedlist>
</sect3>
-
-
+
+
<sect3>
<title><application>psql</> Changes</title>
<itemizedlist>
<listitem>
<para>
- Add psql <command>\set ON_ERROR_ROLLBACK</> to allow statements
- in a transaction to error without affecting the rest of the
+ Add <command>\set ON_ERROR_ROLLBACK</> to allow statements in
+ a transaction to error without affecting the rest of the
transaction (Greg Sabino Mullane)
</para>
<para>
<listitem>
<para>
- Add support for <literal>\x</> hex strings in psql variables
- (Bruce)
+ Add support for <literal>\x</> hex strings in
+ <application>psql</> variables (Bruce)
</para>
<para>
Octal escapes were already supported.
<listitem>
<para>
- Add psql support for <command>troff -ms</> output format (Roger
+ Add support for <command>troff -ms</> output format (Roger
Leigh)
</para>
</listitem>
<listitem>
<para>
- Allow psql's history file location to be controlled by
+ Allow the history file location to be controlled by
<envar>HISTFILE</> (Andreas Seltenreich)
</para>
<para>
<listitem>
<para>
- Prevent psql <command>\x</> (expanded mode) from affecting
+ Prevent <command>\x</> (expanded mode) from affecting
backslash-command displays (Neil)
</para>
</listitem>
<listitem>
<para>
- Add <option>-L</> option to psql to log sessions (Lorne Sunley)
+ Add <option>-L</> option to <application>psql</application> to
+ log sessions (Lorne Sunley)
</para>
<para>
This option was added because some operating systems do not have
<listitem>
<para>
- Make psql <command>\d</> show tablespaces of indexes (Qingqing
+ Make <command>\d</> show the tablespaces of indexes (Qingqing
Zhou)
</para>
</listitem>
<listitem>
<para>
- Allow psql help (<command>\h</>) to make a best guess on the
- proper help information (Greg Sabino Mullane)
+ Allow <application>psql</application> help (<command>\h</>) to
+ make a best guess on the proper help information (Greg Sabino
+ Mullane)
</para>
<para>
This allows the user to just add <command>\h</> to the front of
<listitem>
<para>
- Add psql <command>\pset numericlocale</> to allow numbers to be
+ Add <command>\pset numericlocale</> to allow numbers to be
output in a locale-aware format (Eugen Nedelcu)
</para>
<para>
<listitem>
<para>
Allow <application>pg_dump</> to dump a consistent snapshot of
- large objects
- (Tom)
+ large objects (Tom)
</para>
</listitem>
<sect3>
- <title>libpq Changes</title>
+ <title><application>libpq</application> Changes</title>
<itemizedlist>
<listitem>
<para>
Add a <envar>PGPASSFILE</> environment variable to specify the
- password file's filename (Andrew Dunstan)
+ password file's filename (Andrew)
</para>
</listitem>
<listitem>
<para>
Add spinlock support for the Itanium processor using Intel
- compiler (Vikram
- Kalsi)
+ compiler (Vikram Kalsi)
</para>
</listitem>
<listitem>
<para>
- Add support for wal_fsync_writethrough for Darwin (Chris
- Campbell)
+ Add support for <literal>fsync_writethrough</literal> on
+ Darwin (Chris Campbell)
</para>
</listitem>
<listitem>
<para>
- Allow <application>pg_config</> to be compiled using MSVC (Andrew
- Dunstan)
+ Allow <application>pg_config</> to be compiled using MSVC (Andrew)
</para>
<para>
This is required to build DBD::Pg using <application>MSVC</>.
</para>
<para>
Kerberos 4 had security vulnerabilities and is no longer being
- maintained by the authors.
+ maintained.
</para>
</listitem>
<listitem>
<para>
- Allow libpq to be built thread-safe on Windows (Dave Page)
+ Allow <application>libpq</application> to be built thread-safe
+ on Windows (Dave Page)
</para>
</listitem>
<listitem>
<para>
- implementation of OpenPGP symmetric-key and public-key encryption
+ Implementation of OpenPGP symmetric-key and public-key encryption
</para>
<para>
Both RSA and Elgamal public-key algorithms are supported.
<listitem>
<para>
- Take build parameters (OpenSSL, zlib) from <filename>./configure</> result
+ Take build parameters (OpenSSL, zlib) from <filename>configure</> result
</para>
<para>
No need to edit the <filename>Makefile</> anymore.
projects / postgresql / commitdiff