taken automatically, but this is only true with respect to user tables.
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+$PostgreSQL: pgsql/doc/src/sgml/mvcc.sgml,v 2.47 2005/02/26 18:37:17 tgl Exp $
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<chapter id="mvcc">
</para>
<para>
- This lock mode is not automatically acquired by any
- <productname>PostgreSQL</productname> command.
+ This lock mode is not automatically acquired on user tables by any
+ <productname>PostgreSQL</productname> command. However it is
+ acquired on certain system catalogs in some operations.
</para>
</listitem>
</varlistentry>