<para>

Acquired by <command>VACUUM</command> (without <option>FULL</option>),

<command>ANALYZE</>, and <command>CREATE INDEX CONCURRENTLY</>.

<command>ANALYZE</>, <command>CREATE INDEX CONCURRENTLY</>, and

some forms of <command>ALTER TABLE</command>.

</para>

</listitem>

</varlistentry>

<para>

Acquired by <command>CREATE TRIGGER</command>,

<command>CREATE RULE</command> (except for <literal>ON SELECT</>

rules) andinsomecases <command>ALTER TABLE</command>.

rules) and someforms of <command>ALTER TABLE</command>.

</para>

</listitem>

</varlistentry>

Acquired by the <command>DROP TABLE</command>,

<command>TRUNCATE</command>, <command>REINDEX</command>,

<command>CLUSTER</command>, and <command>VACUUM FULL</command>

commands,as well as most variants of <command>ALTER TABLE</>.

commands,and some forms of <command>ALTER TABLE</>.

This is also the default lock mode for <command>LOCK TABLE</command>

statements that do not specify a mode explicitly.

</para>