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

<title>Release 9.0</title>

<para>

Version 9.0 contains a number of changes that selectively break backwards

compatibility in order to support new features and code quality

improvements. Particularly, users who make extensive use of PL/pgSQL

and/or PITR and Warm Standby should test their solutions for breakage.

improvements. Also, users who make extensive use of PL/pgSQL,

Point-In-Time Recovery (PITR), and Warm Standby should test their

solutions because of slight user-visible changes in these areas.

Observe the following incompatibilities:

</para>

<listitem>

<para>

Replace server parameter <varname>archive_mode</> with

<link linkend="guc-wal-level"><varname>wal_level</></link>

(Heikki Linnakangas)

<link linkend="guc-archive-mode"><varname>archive_mode</></link>

now only affects <link

linkend="guc-archive-command"><varname>archive_command</></link>;

a new setting, <link

linkend="guc-wal-level"><varname>wal_level</></link>, affects

the contents of the write-ahead log (Heikki Linnakangas)

</para>

</listitem>