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PostgreSQL documentation

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<term><literal>RESET ( <replaceable class="PARAMETER">attribute_option</replaceable> [, ... ] )</literal></term>

<listitem>

<para>

This form sets or resetsattribute-level options. Currently, the only

define attribute-level options are <literal>n_distinct</> and

This form sets or resetsper-attribute options. Currently, the only

defined per-attribute options are <literal>n_distinct</> and

<literal>n_distinct_inherited</>, which override the

number-of-distinct-valuesestimate made by subsequent

number-of-distinct-valuesestimates made by subsequent

<xref linkend="sql-analyze">

operations. <literal>n_distinct</> affects the statistics for the table

itself, while <literal>n_distinct_inherited</> affects the statistics

gathered for the tableand its inheritance children. When set to a

gathered for the tableplus its inheritance children. When set to a

positive value, <command>ANALYZE</> will assume that the column contains

exactly the specified number of distinct nonnull values. When set to a

negative value, which must be greater

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

<title>Release 9.0</title>

<note>

<title>Release date</title>

<simpara>2010-??-??</simpara>

<simpara>2010-09-20</simpara>

</note>

<para>CURRENT AS OF 2010-08-24</para>

<sect2>

<title>Overview</title>

SCHEMA</></link> supports mass permissions changes on existing objects,

while <link linkend="SQL-ALTERDEFAULTPRIVILEGES"><command>ALTER DEFAULT

PRIVILEGES</></link> allows control of privileges for objects created in

the future. Large objects (BLOBs) now supportprivilege management as

the future. Large objects (BLOBs) now supportpermissions management as

well.

</para>

</listitem>

<para>

Version 9.0 contains a number of changes that selectively break backwards

compatibility in order to support new features and code quality

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 inthese areas.

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

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

applications because of slight user-visible changes inthose areas.

Observe the following incompatibilities:

</para>

<listitem>

<para>

Allow setting of distinct statistics using <link

Allow setting ofnumber-of-distinct-values statistics using <link

linkend="SQL-ALTERTABLE"><command>ALTER TABLE</></link>

(Robert Haas)

</para>

linkend="monitoring-stats-funcs-table"><function>pg_stat_reset_single_table_counters()</></link>

and <function>pg_stat_reset_single_function_counters()</>

to allow resetting the statistics counters for individual

tables andindexes (Magnus Hagander)

tables andfunctions (Magnus Hagander)

</para>

</listitem>

<para>

Previously only per-database and per-role settings were possible,

not combinations. All role and database settings are now stored

in the new <structname>pg_db_role_setting</> systemtable. A new

in the new <structname>pg_db_role_setting</> systemcatalog. A new

<application>psql</> command <literal>\drds</> shows these settings.

The legacy system views <structname>pg_roles</>,

<structname>pg_shadow</>, and <structname>pg_user</>

known to the server. This allows the server to correctly check that

superuser-only parameters are only set by superusers. Previously,

the <literal>SET</> would be allowed and then ignored at session start,

making superuser-only custom parameters practically useless.

making superuser-only custom parameters much less useful than they

should be.

</para>

</listitem>

<listitem>

<para>

Add Unicode surrogatepair (dual 16-bit) support to

Support Unicode surrogatepairs (dual 16-bit representation) in

<link

linkend="sql-syntax-strings-uescape"><literal>U&amp;</></link>

strings and identifiers (Peter Eisentraut)

<listitem>

<para>

Addsupportfor copying allattributes in <command>CREATE

Adda shortcutfor copying allproperties in <command>CREATE

TABLE ... LIKE</> commands (Itagaki Takahiro)

</para>

</listitem>

<listitem>

<para>

Support locale-specific <link

linkend="functions-posix-regexp">regular expression</link>

processing with <acronym>UTF-8</> server encoding (Tom Lane)

Allow function calls to supply parameter names and match them to named

parameters in the function definition (Pavel Stehule)

</para>

<para>

Locale-specific regular expression functionality includes

case-insensitive matching and locale-specific character classes.

Previously, these features only worked correctly for

non-<acronym>ASCII</> characters when using a single-byte server

encoding (such as LATIN1). They will still misbehave in multi-byte

encodings other than <acronym>UTF-8</>.

For example, if a function is defined to take parameters <literal>a</>

and <literal>b</>, it can be called with <literal>func(a := 7, b

:= 12)</> or <literal>func(b := 12, a := 7)</>.

</para>

</listitem>

<listitem>

<para>

Allow function calls to supply parameter names and match them to named

parameters in the function definition (Pavel Stehule)

Support locale-specific <link

linkend="functions-posix-regexp">regular expression</link>

processing with <acronym>UTF-8</> server encoding (Tom Lane)

</para>

<para>

For example, if a function is defined to take parameters <literal>a</>

and <literal>b</>, it can be called with <literal>func(a := 7, b

:= 12)</> or <literal>func(b := 12, a := 7)</>.

Locale-specific regular expression functionality includes

case-insensitive matching and locale-specific character classes.

Previously, these features worked correctly for non-<acronym>ASCII</>

characters only if the database used a single-byte server encoding (such

as LATIN1). They will still misbehave in multi-byte encodings other

than <acronym>UTF-8</>.

</para>

</listitem>

rather than whenever the enclosing expression is reached. For

example, many people have tried to do this in triggers:

<programlisting>

if TG_OP = 'INSERT'AND NEW.col1 = ... then

if TG_OP = 'INSERT'and NEW.col1 = ... then

</programlisting>

This will now actually work as expected.

</para>

<listitem>

<para>

Add<link linkend="APP-VACUUMDB"><command>vacuumdb</></link>

<option>--analyze-only</> optionto analyze without vacuuming

(Bruce Momjian)

Addan <option>--analyze-only</> option to <link

linkend="APP-VACUUMDB"><command>vacuumdb</></link>,to analyze without

vacuuming(Bruce Momjian)

</para>

</listitem>

<listitem>

<para>

Load SSL certificate chains (Tom Lane)

Load all SSL certificates given in the client certificate file

(Tom Lane)

</para>

<para>

<listitem>

<para>

Add the <link linkend="ecpg-descriptors"><command>DESCRIBE</>

[<literal>OUTPUT</>]</link> statement to <application>ecpg</>

[<literal>OUTPUT</>]</link> statement to <application>ecpg</>

(Boszormenyi Zoltan)

</para>

</listitem>

<listitem>

<para>

Add an <application>ecpg</> function <link

linkend="ecpg-library">ECPGtransactionStatus</link> to return the

current transaction status (Bernd Helmle)

Add an <link linkend="ecpg-library">ECPGtransactionStatus</link>

function to return the current transaction status (Bernd Helmle)

</para>

</listitem>

</para>

<para>

Thread-safe builds can be disabled with <link

The thread-safety option can be disabled with <link

linkend="configure"><literal>configure</></link>

<option>--disable-thread-safety</>.

</para>

<para>

These are similar to the existing <literal>all</>, <literal>install</>,

and <literal>installcheck</> targets, but they also build

and <literal>installcheck</> targets, but they also build the

<acronym>HTML</> documentation, build and test <filename>contrib</>,

and test server-side languages and <application>ecpg</>.

</para>

<listitem>

<para>

Add Makefile rules to builddocumentation as a single <acronym>HTML</>

file or as a single plain-text file

Add Makefile rules to buildthe <productname>PostgreSQL</> documentation

as a single <acronym>HTML</>file or as a single plain-text file

(Peter Eisentraut, Bruce Momjian)

</para>

</listitem>

<para>

Existing calls will still work for the moment, but can be expected to

break in 9.1 or later if not converted.

break in 9.1 or later if not converted to the new style.

</para>

</listitem>

</para>

</listitem>

<listitem>

<para>

Allow the calling of parser hooks from <acronym>SPI</> and cached

plans (Tom Lane)

</para>

</listitem>

<listitem>

<para>

Add a ProcessUtility hook so loadable modules can control utility