]> granicus.if.org Git - postgresql/blobdiff - doc/src/sgml/ref/reset.sgml
RESET SESSION, plus related new DDL commands. Patch from Marko Kreen,
[postgresql] / doc / src / sgml / ref / reset.sgml
index 79b3b7d73c39270dcd639fdd92f6e0fcd3b5f4c9..e94ef0b8d57e7d98105867262a818f649be0f7aa 100644 (file)
-<REFENTRY ID="SQL-RESET">
-<REFMETA>
-<REFENTRYTITLE>
-RESET
-</REFENTRYTITLE>
-<REFMISCINFO>SQL - Language Statements</REFMISCINFO>
-</REFMETA>
-<REFNAMEDIV>
-<REFNAME>
-RESET
-</REFNAME>
-<REFPURPOSE>
-Restores run-time parameters for session to default values
-</REFPURPOSE>
-  </refnamediv>
-<REFSYNOPSISDIV>
-<REFSYNOPSISDIVINFO>
-<DATE>1998-09-24</DATE>
-</REFSYNOPSISDIVINFO>
-<SYNOPSIS>
-RESET <REPLACEABLE CLASS="PARAMETER">variable</REPLACEABLE>
-</SYNOPSIS>
-
-       <REFSECT2 ID="R2-SQL-RESET-1">
-         <REFSECT2INFO>
-               <DATE>1998-09-24</DATE>
-         </REFSECT2INFO>
-         <TITLE>
-               Inputs
-         </TITLE>
-         <PARA>                
-               <VARIABLELIST>
-                 <VARLISTENTRY>
-                       <TERM>
-                         <REPLACEABLE CLASS="PARAMETER">variable</REPLACEABLE>
-                       </TERM>
-                       <LISTITEM>
-                         <PARA>
-                               Refer to the SET statement for more information on available
-                               variables.
-                         </para>
-                       </listitem>
-                 </varlistentry>
-               </variablelist>
-         </para>
-       </REFSECT2>
-
-       <REFSECT2 ID="R2-SQL-RESET-2">
-         <REFSECT2INFO>
-               <DATE>1998-09-24</DATE>
-         </REFSECT2INFO>
-         <TITLE>
-               Outputs
-         </TITLE>
-         <PARA>
-               
-               <VARIABLELIST>
-                 <VARLISTENTRY>
-                       <TERM>
-                         RESET VARIABLE
-                       </TERM>
-                       <LISTITEM>
-                         <PARA>
-                               Message returned if 
-                               <REPLACEABLE CLASS="PARAMETER">variable</REPLACEABLE> is successfully reset
-                               to its default value..
-                         </para>
-                       </listitem>
-                 </varlistentry>
-               </VARIABLELIST>
-         </para>
-       </REFSECT2>
-  </REFSYNOPSISDIV>
-  
-  <REFSECT1 ID="R1-SQL-RESET-1">
-       <REFSECT1INFO>
-         <DATE>1998-09-24</DATE>
-       </REFSECT1INFO>
-       <TITLE>
-         Description
-       </TITLE>
-       <PARA>
-         <command>RESET</command> restores variables to the
-         default values.
-         Refer to the <command>SET</command> command for details on
-         allowed values and defaults.
-         <command>RESET</command> is an alternate form for
-         <synopsis>
-               <command>SET <replaceable class="parameter">variable</replaceable> = DEFAULT</command>
-         </synopsis>
-       </para>
-
-       <REFSECT2 ID="R2-SQL-RESET-3">
-         <REFSECT2INFO>
-               <DATE>1998-09-24</DATE>
-         </REFSECT2INFO>
-         <TITLE>
-               Notes
-         </TITLE>
-         <PARA>
-               The RESET statement is a <productname>Postgres</productname> language extension.
-         </para>
-         <para>
-                 Refer to SET/SHOW statements to set/show variable values.
-         </para>
-       </REFSECT2>
-  </refsect1>
-  
-  <REFSECT1 ID="R1-SQL-RESET-2">
-       <TITLE>
-         Usage
-       </TITLE>
-       <PARA>
-         <ProgramListing>
-               -- reset DateStyle to its default;
-               RESET DateStyle;
-         </programlisting>
-         <programlisting>   
-               -- reset Geqo to its default;
-               RESET GEQO;
-         </ProgramListing>
-       </para>
-  </REFSECT1>
-
-  <REFSECT1 ID="R1-SQL-RESET-3">
-       <TITLE>
-         Compatibility
-       </TITLE>
-
-       <REFSECT2 ID="R2-SQL-RESET-4">
-         <REFSECT2INFO>
-               <DATE>1998-09-24</DATE>
-         </REFSECT2INFO>
-         <TITLE>
-               SQL92
-         </TITLE>
-         <PARA>
-               There is no <command>RESET</command> in <acronym>SQL92</acronym>.
-         </para>
-       </refsect2>
-  </refsect1>
-</REFENTRY>
+<!--
+$PostgreSQL: pgsql/doc/src/sgml/ref/reset.sgml,v 1.33 2007/04/12 06:53:46 neilc Exp $
+PostgreSQL documentation
+-->
+
+<refentry id="SQL-RESET">
+ <refmeta>
+  <refentrytitle id="SQL-RESET-TITLE">RESET</refentrytitle>
+  <refmiscinfo>SQL - Language Statements</refmiscinfo>
+ </refmeta>
+
+ <refnamediv>
+  <refname>RESET</refname>
+  <refpurpose>restore the value of a run-time parameter to the default value</refpurpose>
+ </refnamediv>
+
+ <indexterm zone="sql-reset">
+  <primary>RESET</primary>
+ </indexterm>
+
+ <refsynopsisdiv>
+<synopsis>
+RESET <replaceable class="PARAMETER">configuration_parameter</replaceable>
+RESET ALL
+RESET { PLANS | SESSION | TEMP | TEMPORARY }
+</synopsis>
+ </refsynopsisdiv>
+
+ <refsect1>
+  <title>Description</title>
+
+  <para>
+   <command>RESET</command> restores run-time parameters to their
+   default values.  <command>RESET</command> is an alternative
+   spelling for
+<synopsis>
+SET <replaceable class="parameter">configuration_parameter</replaceable> TO DEFAULT
+</synopsis>
+   Refer to <xref linkend="sql-set" endterm="sql-set-title"> for
+   details.
+  </para>
+
+  <para>
+   The default value is defined as the value that the parameter would
+   have had, if no <command>SET</> ever been issued for it in the
+   current session.  The actual source of this value might be a
+   compiled-in default, the configuration file, command-line options,
+   or per-database or per-user default settings.  See <xref
+   linkend="runtime-config"> for details.
+  </para>
+
+  <para>
+   See the <command>SET</> reference page for details on the
+   transaction behavior of <command>RESET</>.
+  </para>
+
+  <para>
+   <command>RESET</> can also be used to release internal resources
+   that are usually released at the end of session.  <command>RESET
+   TEMP</> drops all temporary tables created in the current session.
+   <command>RESET PLANS</> releases all internally cached plans.
+   <command>RESET SESSION</> releases all externally visible temporary
+   resources associated with the current session.
+  </para>
+ </refsect1>
+
+ <refsect1>
+  <title>Parameters</title>
+
+  <variablelist>
+   <varlistentry>
+    <term><replaceable class="PARAMETER">configuration_parameter</replaceable></term>
+    <listitem>
+     <para>
+      The name of a run-time parameter. See <xref linkend="sql-set"
+      endterm="sql-set-title"> for a list.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
+    <term><literal>ALL</literal></term>
+    <listitem>
+     <para>
+      Resets all settable run-time parameters to default values.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
+    <term><literal>TEMP, TEMPORARY</literal></term>
+    <listitem>
+     <para>
+      Drops all temporary tables created in the current session.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
+    <term><literal>PLANS</literal></term>
+    <listitem>
+     <para>
+      Releases all cached query plans.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
+    <term><literal>SESSION</literal></term>
+    <listitem>
+     <para>
+      Releases all temporary resources associated with the current
+      session. This has the same effect as executing the following
+      command sequence:
+<synopsis>
+SET SESSION AUTHORIZATION DEFAULT;
+RESET ALL;
+DEALLOCATE ALL;
+CLOSE ALL;
+UNLISTEN *;
+RESET PLANS;
+RESET TEMP;
+</synopsis>
+     </para>
+    </listitem>
+   </varlistentry>
+
+  </variablelist>
+ </refsect1>
+
+ <refsect1>
+  <title>Notes</title>
+
+   <para>
+    <command>RESET SESSION</> cannot be executed inside a transaction block.
+   </para>
+ </refsect1>
+
+ <refsect1>
+  <title>Examples</title>
+
+  <para>
+   Set the <varname>geqo</> configuration variable to its default value:
+<screen>
+RESET geqo;
+</screen>
+  </para>
+ </refsect1>
+
+ <refsect1>
+  <title>Compatibility</title>
+
+  <para>
+   <command>RESET</command> is a <productname>PostgreSQL</productname> extension.
+  </para>
+ </refsect1>
+</refentry>