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e4128ee767
This adds a new object type "procedure" that is similar to a function but does not have a return type and is invoked by the new CALL statement instead of SELECT or similar. This implementation is aligned with the SQL standard and compatible with or similar to other SQL implementations. This commit adds new commands CALL, CREATE/ALTER/DROP PROCEDURE, as well as ALTER/DROP ROUTINE that can refer to either a function or a procedure (or an aggregate function, as an extension to SQL). There is also support for procedures in various utility commands such as COMMENT and GRANT, as well as support in pg_dump and psql. Support for defining procedures is available in all the languages supplied by the core distribution. While this commit is mainly syntax sugar around existing functionality, future features will rely on having procedures as a separate object type. Reviewed-by: Andrew Dunstan <andrew.dunstan@2ndquadrant.com>
367 lines
12 KiB
Plaintext
367 lines
12 KiB
Plaintext
<!--
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doc/src/sgml/ref/alter_function.sgml
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PostgreSQL documentation
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-->
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<refentry id="sql-alterfunction">
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<indexterm zone="sql-alterfunction">
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<primary>ALTER FUNCTION</primary>
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</indexterm>
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<refmeta>
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<refentrytitle>ALTER FUNCTION</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>ALTER FUNCTION</refname>
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<refpurpose>change the definition of a function</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<synopsis>
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ALTER FUNCTION <replaceable>name</replaceable> [ ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">argtype</replaceable> [, ...] ] ) ]
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<replaceable class="parameter">action</replaceable> [ ... ] [ RESTRICT ]
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ALTER FUNCTION <replaceable>name</replaceable> [ ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">argtype</replaceable> [, ...] ] ) ]
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RENAME TO <replaceable>new_name</replaceable>
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ALTER FUNCTION <replaceable>name</replaceable> [ ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">argtype</replaceable> [, ...] ] ) ]
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OWNER TO { <replaceable>new_owner</replaceable> | CURRENT_USER | SESSION_USER }
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ALTER FUNCTION <replaceable>name</replaceable> [ ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">argtype</replaceable> [, ...] ] ) ]
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SET SCHEMA <replaceable>new_schema</replaceable>
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ALTER FUNCTION <replaceable>name</replaceable> [ ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">argtype</replaceable> [, ...] ] ) ]
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DEPENDS ON EXTENSION <replaceable>extension_name</replaceable>
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<phrase>where <replaceable class="parameter">action</replaceable> is one of:</phrase>
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CALLED ON NULL INPUT | RETURNS NULL ON NULL INPUT | STRICT
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IMMUTABLE | STABLE | VOLATILE | [ NOT ] LEAKPROOF
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[ EXTERNAL ] SECURITY INVOKER | [ EXTERNAL ] SECURITY DEFINER
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PARALLEL { UNSAFE | RESTRICTED | SAFE }
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COST <replaceable class="parameter">execution_cost</replaceable>
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ROWS <replaceable class="parameter">result_rows</replaceable>
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SET <replaceable class="parameter">configuration_parameter</replaceable> { TO | = } { <replaceable class="parameter">value</replaceable> | DEFAULT }
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SET <replaceable class="parameter">configuration_parameter</replaceable> FROM CURRENT
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RESET <replaceable class="parameter">configuration_parameter</replaceable>
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RESET ALL
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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>ALTER FUNCTION</command> changes the definition of a
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function.
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</para>
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<para>
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You must own the function to use <command>ALTER FUNCTION</command>.
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To change a function's schema, you must also have <literal>CREATE</literal>
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privilege on the new schema.
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To alter the owner, you must also be a direct or indirect member of the new
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owning role, and that role must have <literal>CREATE</literal> privilege on
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the function's schema. (These restrictions enforce that altering the owner
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doesn't do anything you couldn't do by dropping and recreating the function.
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However, a superuser can alter ownership of any function anyway.)
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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><replaceable class="parameter">name</replaceable></term>
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<listitem>
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<para>
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The name (optionally schema-qualified) of an existing function. If no
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argument list is specified, the name must be unique in its schema.
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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><replaceable class="parameter">argmode</replaceable></term>
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<listitem>
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<para>
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The mode of an argument: <literal>IN</literal>, <literal>OUT</literal>,
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<literal>INOUT</literal>, or <literal>VARIADIC</literal>.
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If omitted, the default is <literal>IN</literal>.
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Note that <command>ALTER FUNCTION</command> does not actually pay
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any attention to <literal>OUT</literal> arguments, since only the input
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arguments are needed to determine the function's identity.
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So it is sufficient to list the <literal>IN</literal>, <literal>INOUT</literal>,
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and <literal>VARIADIC</literal> arguments.
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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><replaceable class="parameter">argname</replaceable></term>
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<listitem>
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<para>
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The name of an argument.
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Note that <command>ALTER FUNCTION</command> does not actually pay
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any attention to argument names, since only the argument data
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types are needed to determine the function's identity.
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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><replaceable class="parameter">argtype</replaceable></term>
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<listitem>
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<para>
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The data type(s) of the function's arguments (optionally
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schema-qualified), if any.
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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><replaceable class="parameter">new_name</replaceable></term>
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<listitem>
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<para>
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The new name of the function.
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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><replaceable class="parameter">new_owner</replaceable></term>
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<listitem>
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<para>
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The new owner of the function. Note that if the function is
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marked <literal>SECURITY DEFINER</literal>, it will subsequently
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execute as the new owner.
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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><replaceable class="parameter">new_schema</replaceable></term>
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<listitem>
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<para>
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The new schema for the function.
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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><replaceable class="parameter">extension_name</replaceable></term>
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<listitem>
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<para>
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The name of the extension that the function is to depend on.
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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>CALLED ON NULL INPUT</literal></term>
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<term><literal>RETURNS NULL ON NULL INPUT</literal></term>
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<term><literal>STRICT</literal></term>
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<listitem>
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<para><literal>CALLED ON NULL INPUT</literal> changes the function so
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that it will be invoked when some or all of its arguments are
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null. <literal>RETURNS NULL ON NULL INPUT</literal> or
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<literal>STRICT</literal> changes the function so that it is not
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invoked if any of its arguments are null; instead, a null result
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is assumed automatically. See <xref linkend="sql-createfunction"/>
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for more information.
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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>IMMUTABLE</literal></term>
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<term><literal>STABLE</literal></term>
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<term><literal>VOLATILE</literal></term>
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<listitem>
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<para>
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Change the volatility of the function to the specified setting.
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See <xref linkend="sql-createfunction"/> for details.
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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><optional> EXTERNAL </optional> SECURITY INVOKER</literal></term>
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<term><literal><optional> EXTERNAL </optional> SECURITY DEFINER</literal></term>
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<listitem>
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<para>
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Change whether the function is a security definer or not. The
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key word <literal>EXTERNAL</literal> is ignored for SQL
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conformance. See <xref linkend="sql-createfunction"/> for more information about
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this capability.
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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>PARALLEL</literal></term>
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<listitem>
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<para>
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Change whether the function is deemed safe for parallelism.
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See <xref linkend="sql-createfunction"/> for details.
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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>LEAKPROOF</literal></term>
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<listitem>
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<para>
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Change whether the function is considered leakproof or not.
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See <xref linkend="sql-createfunction"/> for more information about
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this capability.
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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>COST</literal> <replaceable class="parameter">execution_cost</replaceable></term>
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<listitem>
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<para>
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Change the estimated execution cost of the function.
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See <xref linkend="sql-createfunction"/> for more information.
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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>ROWS</literal> <replaceable class="parameter">result_rows</replaceable></term>
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<listitem>
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<para>
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Change the estimated number of rows returned by a set-returning
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function. See <xref linkend="sql-createfunction"/> for more information.
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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><replaceable>configuration_parameter</replaceable></term>
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<term><replaceable>value</replaceable></term>
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<listitem>
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<para>
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Add or change the assignment to be made to a configuration parameter
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when the function is called. If
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<replaceable>value</replaceable> is <literal>DEFAULT</literal>
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or, equivalently, <literal>RESET</literal> is used, the function-local
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setting is removed, so that the function executes with the value
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present in its environment. Use <literal>RESET
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ALL</literal> to clear all function-local settings.
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<literal>SET FROM CURRENT</literal> saves the value of the parameter that
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is current when <command>ALTER FUNCTION</command> is executed as the value
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to be applied when the function is entered.
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</para>
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<para>
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See <xref linkend="sql-set"/> and
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<xref linkend="runtime-config"/>
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for more information about allowed parameter names and values.
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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>RESTRICT</literal></term>
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<listitem>
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<para>
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Ignored for conformance with the SQL standard.
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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>Examples</title>
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<para>
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To rename the function <literal>sqrt</literal> for type
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<type>integer</type> to <literal>square_root</literal>:
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<programlisting>
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ALTER FUNCTION sqrt(integer) RENAME TO square_root;
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</programlisting>
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</para>
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<para>
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To change the owner of the function <literal>sqrt</literal> for type
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<type>integer</type> to <literal>joe</literal>:
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<programlisting>
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ALTER FUNCTION sqrt(integer) OWNER TO joe;
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</programlisting>
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</para>
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<para>
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To change the schema of the function <literal>sqrt</literal> for type
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<type>integer</type> to <literal>maths</literal>:
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<programlisting>
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ALTER FUNCTION sqrt(integer) SET SCHEMA maths;
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</programlisting>
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</para>
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<para>
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To mark the function <literal>sqrt</literal> for type
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<type>integer</type> as being dependent on the extension
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<literal>mathlib</literal>:
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<programlisting>
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ALTER FUNCTION sqrt(integer) DEPENDS ON EXTENSION mathlib;
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</programlisting>
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</para>
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<para>
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To adjust the search path that is automatically set for a function:
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<programlisting>
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ALTER FUNCTION check_password(text) SET search_path = admin, pg_temp;
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</programlisting>
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</para>
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<para>
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To disable automatic setting of <varname>search_path</varname> for a function:
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<programlisting>
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ALTER FUNCTION check_password(text) RESET search_path;
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</programlisting>
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The function will now execute with whatever search path is used by its
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caller.
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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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This statement is partially compatible with the <command>ALTER
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FUNCTION</command> statement in the SQL standard. The standard allows more
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properties of a function to be modified, but does not provide the
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ability to rename a function, make a function a security definer,
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attach configuration parameter values to a function,
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or change the owner, schema, or volatility of a function. The standard also
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requires the <literal>RESTRICT</literal> key word, which is optional in
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<productname>PostgreSQL</productname>.
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</para>
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</refsect1>
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<refsect1>
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<title>See Also</title>
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<simplelist type="inline">
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<member><xref linkend="sql-createfunction"/></member>
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<member><xref linkend="sql-dropfunction"/></member>
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<member><xref linkend="sql-alterprocedure"/></member>
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<member><xref linkend="sql-alterroutine"/></member>
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</simplelist>
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</refsect1>
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</refentry>
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