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<chapter id="plperl">

<title>PL/Perl - Perl Procedural Language</title>

If the above function was created by a superuser using the language

<literal>plperlu</>, execution would succeed.

</para>

<note>

<para>

For security reasons, to stop a leak of privileged operations from

<application>PL/PerlU</> to <application>PL/Perl</>, these two languages

have to run in separate instances of the Perl interpreter. If your

Perl installation has been appropriately compiled, this is not a problem.

However, not all installations are compiled with the requisite flags.

If <productname>PostgreSQL</> detects that this is the case then it will

not start a second interpreter, but instead create an error. In

consequence, in such an installation, you cannot use both

<application>PL/PerlU</> and <application>PL/Perl</> in the same backend

process. The remedy for this is to obtain a Perl installation created

with the appropriate flags, namely either <literal>usemultiplicity</> or

both <literal>usethreads</> and <literal>useithreads</>.

For more details,see the <literal>perlembed</> manual page.

</para>

</note>

</sect1>

<sect1 id="plperl-triggers">

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</para>

</listitem>

<listitem>

<para>

Data can no longer be shared between a PL/Perl function and a

PL/PerlU function, and modules used by a /PerlU function are no

longer available to PL/Perl functions.

</para>

<para>

Some perl installations have not been compiled with the correct flags

to allow multiple interpreters to exist within a single process.

In this situation PL/Perl and PL/PerlU cannot both be used in a

single backend. The solution is to get a Perl installation which

supports multiple interpreters. (Andrew)

</para>

</listitem>

<listitem>

<para>

In <filename>contrib/xml2/</>, rename <function>xml_valid()</> to

<para>

Previously, it was lexical, which caused unexpected sharing

violations.

</para>

</listitem>

</para>

</listitem>

<listitem>

<para>

Run PL/Perl and PL/PerlU in separate interpreters, for security

reasons.

</para>

<para>

In consequence, they can no longer share data nor loaded modules.

Also, if Perl has not been compiled with the requisite flags to

allow multiple interpreters, only one of these lamguages can be used

in any given backend process. (Andrew)

</para>

</listitem>

</itemizedlist>