e309739670
that the presented list of equivalent operations is meant to be the primary definition of what it does. Per comment from Guillaume Smet.
110 lines
2.5 KiB
Plaintext
110 lines
2.5 KiB
Plaintext
<!--
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$PostgreSQL: pgsql/doc/src/sgml/ref/discard.sgml,v 1.5 2008/11/27 00:28:06 tgl Exp $
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PostgreSQL documentation
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-->
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<refentry id="SQL-DISCARD">
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<refmeta>
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<refentrytitle id="SQL-DISCARD-TITLE">DISCARD</refentrytitle>
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<manvolnum>7</manvolnum>
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<refmiscinfo>SQL - Language Statements</refmiscinfo>
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</refmeta>
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<refnamediv>
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<refname>DISCARD</refname>
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<refpurpose>discard session state</refpurpose>
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</refnamediv>
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<indexterm zone="sql-discard">
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<primary>DISCARD</primary>
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</indexterm>
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<refsynopsisdiv>
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<synopsis>
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DISCARD { ALL | PLANS | TEMPORARY | TEMP }
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</synopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para>
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<command>DISCARD</> releases internal resources associated with a
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database session. These resources are normally released at the end
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of the session.
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</para>
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<para>
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<command>DISCARD TEMP</> drops all temporary tables created in the
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current session. <command>DISCARD PLANS</> releases all internally
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cached query plans. <command>DISCARD ALL</> resets a session to
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its original state, discarding temporary resources and resetting
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session-local configuration changes.
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</para>
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</refsect1>
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<refsect1>
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<title>Parameters</title>
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<variablelist>
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<varlistentry>
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<term><literal>TEMPORARY</literal> or <literal>TEMP</literal></term>
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<listitem>
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<para>
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Drops all temporary tables created in the current session.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>PLANS</literal></term>
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<listitem>
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<para>
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Releases all cached query plans.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>ALL</literal></term>
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<listitem>
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<para>
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Releases all temporary resources associated with the current
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session and resets the session to its initial state.
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Currently, this has the same effect as executing the following sequence
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of statements:
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<programlisting>
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SET SESSION AUTHORIZATION DEFAULT;
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RESET ALL;
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DEALLOCATE ALL;
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CLOSE ALL;
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UNLISTEN *;
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SELECT pg_advisory_unlock_all();
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DISCARD PLANS;
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DISCARD TEMP;
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</programlisting>
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1>
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<title>Notes</title>
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<para>
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<command>DISCARD ALL</> cannot be executed inside a transaction block.
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</para>
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</refsect1>
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<refsect1>
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<title>Compatibility</title>
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<para>
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<command>DISCARD</command> is a <productname>PostgreSQL</productname> extension.
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</para>
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</refsect1>
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</refentry>
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