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<chapter id="plpgsql">

allow users to define set-returning functions

that do not have this limitation. Currently, the point at

which data begins being written to disk is controlled by the

<varname>work_mem</> configuration variable. Administrators

who have sufficient memory to store larger result sets in

memory should consider increasing this parameter.

<xref linkend="guc-work-mem" xreflabel="work_mem">

configuration variable. Administrators who have sufficient

memory to store larger result sets in memory should consider

increasing this parameter.

</para>

</note>

</sect3>

</para>

<para>

The <replaceable>condition</replaceable> names can be any of those

shown in <xref linkend="errcodes-appendix">. A category name matches

any error within its category.

The special condition name <literal>OTHERS</>

matches every error type except <literal>QUERY_CANCELED</>.

(It is possible, but often unwise, to trap

<literal>QUERY_CANCELED</> by name.)

Condition names are not case-sensitive.

The <replaceable>condition</replaceable> names can be any of

those shown in <xref linkend="errcodes-appendix">. A category

name matches any error within its category. The special

condition name <literal>OTHERS</> matches every error type except

<literal>QUERY_CANCELED</>. (It is possible, but often unwise,

to trap <literal>QUERY_CANCELED</> by name.) Condition names are

not case-sensitive.

</para>

<para>

</para>

<example id="plpgsql-upsert-example">

<title>Exceptions with UPDATE/INSERT</title>

<title>Exceptions with<command>UPDATE</>/<command>INSERT</></title>

<para>

This example uses an <literal>EXCEPTION</> to <command>UPDATE</> or

<command>INSERT</>, as appropriate.

This example uses exception handling to perform either

<command>UPDATE</> or <command>INSERT</>, as appropriate.

<programlisting>

CREATE TABLE db (a INT PRIMARY KEY, b TEXT);

CREATE FUNCTION merge_db(key INT, data TEXT) RETURNS VOID AS

CREATE FUNCTION merge_db(key INT, data TEXT) RETURNS VOID AS

$$

BEGIN

LOOP

$$

LANGUAGE plpgsql;

SELECT merge_db(1, 'david');

SELECT merge_db(1, 'dennis');

SELECT merge_db(1, 'david');

SELECT merge_db(1, 'dennis');

</programlisting>

</para>