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<sect1 id="release-9-0">

<title>Release 9.0</title>

<productname>PostgreSQL</> adds features that have been requested

for years, like easy-to-use replication, a mass permission

facility, and anonymous blocks. While past major releases have

been quite conservative in their scope, this release shows a

bold new desire to provide facilities that every new and existing

user of <productname>PostgreSQL</> will embrace. This has all

been done with few incompatibilities. The major areas of

enhancement are:

been conservative in their scope, this release shows a

bold new desire to provide facilities that new and existing

users of <productname>PostgreSQL</> will embrace. This has all

been done with few incompatibilities. Major enhancements are:

</para>

<itemizedlist>

<para>

Broadly enhanced stored procedure support.

The <link linkend="SQL-DO"><command>DO</></link> statement permits

ad-hoc or anonymous code blocks. Functions can now be called using named

parameters. PL/pgSQL is now installed by default, and PL/Perl and

PL/Python have been enhanced in several ways, including support for

Python3.

anonymous code blocks. Functions can now be called using named

parameters. PL/Perl and PL/Python have been enhanced in several ways,

including support for Python3.

</para>

</listitem>

<para>

Adjust <link

linkend="guc-log-temp-files"><varname>log_temp_files</></link> to

use default filesizes units of kilobytes (Robert Haas)

use default filesize units of kilobytes (Robert Haas)

</para>

</listitem>

<para>

This feature is called Streaming Replication.

Previously <acronym>WAL</> files could be sent to standby systems only

as 16 megabytes files;this allows master changes to be sent to the

as 16 megabytes files;Streaming Replication allows master changes to be sent to the

standby with very little delay. There are new <filename>postgresql.conf</>

and <filename>recovery.conf</> settings to enable this

feature, as well as extensive <link

Outer joins where the inner side is unique and not referenced in

the query are unnecessary and are therefore now removed. This will

accelerate many automatically generated queries, such as those created

by object-relational mappers.

by object-relational mappers (ORM).

</para>

</listitem>

</para>

<para>

This lets DBAs and security stafftoaudit when database settings

This lets DBAs and security staff audit when database settings

were changed.

</para>

<para>

Add <link linkend="SQL-ALTERDEFAULTPRIVILEGES"><command>ALTER

DEFAULT PRIVILEGES</></link> command to control privileges

ofallnewly-created objects (Petr Jelinek)

of newly-created objects (Petr Jelinek)

</para>

<para>

This greatly simplifies the assignment of object privileges in

a complex database application. Defaults currently support tables

a complex database application. Defaults currently support tables,

views, sequences, and functions. Defaults may be assigned on a

per-schema basis or database-wide.

</para>

<para>

This allows <command>UPDATE tab SET col = col + 1</> to work on

columns that have a unique indexes or are marked as primarykeys,

columns that have a unique indexes or are marked as primarykey,

but <literal>DEFERRABLE INITIALLY DEFERRED</> must be used to mark

the constraint as deferred.

</para>

</listitem>

<listitem>

<para>

Generalize uniqueness constraints by allowing arbitrary operator

Exclusion Constraints: generalize uniqueness constraints by allowing arbitrary operator

comparisons, not just equality (Jeff Davis)

</para>

<listitem>

<para>

Implement anonymous functions using the <link

linkend="SQL-DO"><command>DO</></link> statement (Petr

Jelinek, Joshua Tolley, Hannu Valtonen)

linkend="SQL-DO"><command>DO</></link> statement, a.k.a anonymous

blocks (PetrJelinek, Joshua Tolley, Hannu Valtonen)

</para>

<para>

</para>

<para>

This can be enabled with the server variable <link

This can begloballyenabled with the server variable <link

linkend="guc-plperl-use-strict">plperl.use_strict</link>.

</para>

</listitem>

<listitem>

<para>

Add the <literal>string</> data type in <application>ecpg</>

Informix-compatibility mode (ZoltanBoszormenyi)

Informix-compatibility mode (Boszormenyi Zoltan)

</para>

</listitem>

<listitem>

<para>

Allow <application>ecpg</> to use noise words <literal>FROM</> and

<literal>IN</> in <command>FETCH</> and <command>MOVE</> (Zoltan

Boszormenyi)

<literal>IN</> in <command>FETCH</> and <command>MOVE</> (Boszormenyi

Zoltan)

</para>

</listitem>