</para>

<para>

Previously this returned<literal>NULL</>.

Previously this returneda null value.

</para>

</listitem>

</para>

<para>

Previously this returned<literal>NULL</>.

Previously this returneda null value.

</para>

</listitem>

</para>

<para>

Triggers can now be fired in three cases: BEFORE, AFTER, or INSTEAD OF

some action. Trigger function authors should verify that their logic

behaves sanely in all three cases.

Triggers can now be fired in three cases: <literal>BEFORE</>,

<literal>AFTER</>, or <literal>INSTEAD OF</> some action.

Trigger function authors should verify that their logic behaves

sanely in all three cases.

</para>

</listitem>

<listitem>

<para>

Allow unlogged tables using <link

Allow unlogged tables usingthe<link

linkend="SQL-CREATETABLE-description"><literal>UNLOGGED</></link>

during <link linkend="SQL-CREATETABLE"><command>CREATE

clause in <link linkend="SQL-CREATETABLE"><command>CREATE

TABLE</></link> (Robert Haas)

</para>

</para>

<para>

This allows the use of commit_siblings with less overhead.

This allows the use of <varname>commit_siblings</varname> with

less overhead.

</para>

</listitem>

<listitem>

<para>

Support host names and host suffixes (e.g. .example.com) in

<link linkend="auth-pg-hba-conf"><filename>pg_hba.conf</></link>

Support host names and host suffixes

(e.g. <literal>.example.com</>) in <link

linkend="auth-pg-hba-conf"><filename>pg_hba.conf</></link>

(Peter Eisentraut)

</para>

<listitem>

<para>

Support thekeyword <literal>all</> in the host column of <link

Support thekey word <literal>all</> in the host column of <link

linkend="auth-pg-hba-conf"><filename>pg_hba.conf</></link>

(Peter Eisentraut)

</para>

Add <link

linkend="guc-log-file-mode"><varname>log_file_mode</></link>

which controls the permissions on log files created by the

logging_collector (Martin Pihlak)

logging collector (Martin Pihlak)

</para>

</listitem>

<listitem>

<para>

Add <structfield>client_hostname</structfield>field to <link

Add <structfield>client_hostname</structfield>column to <link

linkend="monitoring-stats-views-table"><structname>pg_stat_activity</></link>

(Peter Eisentraut)

</para>

<listitem>

<para>

Add buffers_backend_fsync field to <link

Add<structfield>buffers_backend_fsync</> column to <link

linkend="monitoring-stats-views-table"><structname>pg_stat_bgwriter</></link>

(Greg Smith)

</para>

<para>

This newfield counts the number of times a backend fsyncs a

This newcolumn counts the number of times a backend fsyncs a

buffer.

</para>

</listitem>

</para>

<para>

wal_buffers is now auto-tuned by default based on the size of

shared_buffers.

<varname>wal_buffers</> is now auto-tuned by default based on

the size of <varname>shared_buffers</>.

</para>

</listitem>

<listitem>

<para>

Addvariable <link

Addconfiguration parameter <link

linkend="guc-hot-standby-feedback"><varname>hot_standby_feedback</></link>

to enable standbys to postpone cleanup of old row versions on the

primary (Simon Riggs)

</para>

<para>

This allows a recovery server to be queried to checkif the

recovery point is the one desired.

This allows a recovery server to be queried to checkwhether

therecovery point is the one desired.

</para>

</listitem>

<listitem>

<para>

Add a true <link

linkend="xact-serializable"><literal>serializable</></link> isolation

linkend="xact-serializable">serializable</link> isolation

level (Kevin Grittner, Dan Ports)

</para>

<listitem>

<para>

Allow use of thekeyword <literal>DISTINCT</> in <link

Allow use of thekey word <literal>DISTINCT</> in <link

linkend="queries-union"><literal>UNION</>/<literal>INTERSECT</>/<literal>EXCEPT</></link>

clauses (Tom Lane)

</para>

<para>

<literal>DISTINCT</> is the default behavior so use of this

keyword is redundant, but the SQL standard allows it.

key word is redundant, but the SQL standard allows it.

</para>

</listitem>

<para>

The new option is called <literal>NOT VALID</>, which can

later be modified to <literal>VALIDATED</> and validation

checks performed. Together these allow you to add aForeign Key

checks performed. Together these allow you to add aforeign key

with minimal impact on read and write operations.

</para>

</listitem>

</para>

<para>

For example, converting a varchar column to text no longer

requires a rewrite of the table. However, increasing the length

constraint on a varchar column still requires a table rewrite.

For example, converting a <type>varchar</> column to

<type>text</> no longer requires a rewrite of the table.

However, increasing the length constraint on a

<type>varchar</> column still requires a table rewrite.

</para>

</listitem>

<listitem>

<para>

Fix possible"tuple concurrently updated" error when two server

backends attempted to add an inheritance parent to the same

table at the same time (Robert Haas)

Fix possible<quote>tuple concurrently updated</quote> error

when two serverbackends attempted to add an inheritance

parent to the sametable at the same time (Robert Haas)

</para>

<para>

linkend="array-functions-table"><function>array_to_string()</></link>

and <link

linkend="array-functions-table"><function>string_to_array()</></link>

for<literal>NULL</> processing control (Pavel Stehule)

fornull value processing control (Pavel Stehule)

</para>

</listitem>

<listitem>

<para>

Addfields to the <link

Addcolumns to the <link

linkend="infoschema-sequences"><structname>information_schema.sequences</></link>

system view (Peter Eisentraut)

</para>

<para>

Previously, though the view existed,all of these view fields

were unimplemented.

Previously, though the view existed,the columns about the

sequence parameterswere unimplemented.

</para>

</listitem>

<listitem>

<para>

<function>plpy.Fatal</function> now raises <literal>FATAL</>, rather

than <literal>ERROR</literal> (Jan Urbanski)

</para>

<para>

The old behavior was incorrect.

</para>

</listitem>

<listitem>

<para>

Overhaul of PL/Python (Jan Urbanski)

Fix exception handling with Python 3 (Jan Urbanski)

</para>

<para>

This includes exception support for Python 3. **More detail?

Exception classes were previously not available in

<literal>plpy</> under Python 3.

</para>

</listitem>

<listitem>

<para>

Make <application>psql</application> distinguish between unique

indices and unique constraints (Josh Kupershmidt)

indexes and unique constraints (Josh Kupershmidt)

</para>

</listitem>

<listitem>

<para>

Improve <application>pg_ctl</>

start's "wait" (<option>-w</>) mode to handle non-standard

port numbers, non-standard Unix-domain socket locations,

permission problems, and stale postmaster lock files (Bruce

Momjian)

Improve <application>pg_ctl</> start's <quote>wait</quote>

(<option>-w</>) mode to handle non-standard port numbers,

non-standard Unix-domain socket locations, permission

problems, and stale postmaster lock files (Bruce Momjian)

</para>

</listitem>

</para>

<para>

This allows for faster compiles. Also,make <option>-k</>

and make <option>-q</>nowwork properly in a parallel build.

This allows for faster compiles. Also,<literal>make-k</>

nowworks properly.

</para>

</listitem>

<listitem>

<para>

Improve ability to use C++ compilers for <link

linkend="xfunc-c">backend compiles</link> by removing

conflictingkeywords (Tom Lane)

linkend="xfunc-c">compiling add-on modules</link> by removing

conflictingkey words (Tom Lane)

</para>

</listitem>

<listitem>

<para>

Allow <link linkend="intarray"><filename>contrib/intarray</></link>

to work properly onmulti-dimensional arrays (Tom Lane)

to work properly onmultidimensional arrays (Tom Lane)

</para>

</listitem>

<listitem>

<para>

Document that it is possible to access all composite fields

using <link linkend="field-selection"><literal>(compositeval).*

syntax</></link> (Peter Eisentraut)

Document that it is possible to access all composite type

fields using <link

linkend="field-selection"><literal>(compositeval).*</></link>

syntax (Peter Eisentraut)

</para>

</listitem>