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<!-- doc/src/sgml/vacuumlo.sgml -->
<refentry id="vacuumlo">
<indexterm zone="vacuumlo">
<primary>vacuumlo</primary>
</indexterm>
<refmeta>
<refentrytitle><application>vacuumlo</application></refentrytitle>
<manvolnum>1</manvolnum>
<refmiscinfo>Application</refmiscinfo>
</refmeta>
<refnamediv>
<refname>vacuumlo</refname>
<refpurpose>remove orphaned large objects from a <productname>PostgreSQL</productname> database</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>vacuumlo</command>
<arg choice="opt" rep="repeat"><replaceable>option</replaceable></arg>
<arg choice="plain" rep="repeat"><replaceable>dbname</replaceable></arg>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>
<application>vacuumlo</application> is a simple utility program that will remove any
<quote>orphaned</quote> large objects from a
<productname>PostgreSQL</productname> database. An orphaned large object (LO) is
considered to be any LO whose OID does not appear in any <type>oid</type> or
<type>lo</type> data column of the database.
</para>
<para>
If you use this, you may also be interested in the <function>lo_manage</function>
trigger in the <xref linkend="lo"/> module.
<function>lo_manage</function> is useful to try
to avoid creating orphaned LOs in the first place.
</para>
<para>
All databases named on the command line are processed.
</para>
</refsect1>
<refsect1>
<title>Options</title>
<para>
<application>vacuumlo</application> accepts the following command-line arguments:
<variablelist>
<varlistentry>
<term><option>-l <replaceable class="parameter">limit</replaceable></option></term>
<term><option>--limit=<replaceable class="parameter">limit</replaceable></option></term>
<listitem>
<para>
Remove no more than <replaceable>limit</replaceable> large objects per
transaction (default 1000). Since the server acquires a lock per LO
removed, removing too many LOs in one transaction risks exceeding
<xref linkend="guc-max-locks-per-transaction"/>. Set the limit to
zero if you want all removals done in a single transaction.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-n</option></term>
<term><option>--dry-run</option></term>
<listitem>
<para>Don't remove anything, just show what would be done.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-v</option></term>
<term><option>--verbose</option></term>
<listitem>
<para>Write a lot of progress messages.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-V</option></term>
<term><option>--version</option></term>
<listitem>
<para>
Print the <application>vacuumlo</application> version and exit.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-?</option></term>
<term><option>--help</option></term>
<listitem>
<para>
Show help about <application>vacuumlo</application> command line
arguments, and exit.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
<para>
<application>vacuumlo</application> also accepts the following command-line
arguments for connection parameters:
<variablelist>
<varlistentry>
<term><option>-h <replaceable class="parameter">host</replaceable></option></term>
<term><option>--host=<replaceable class="parameter">host</replaceable></option></term>
<listitem>
<para>Database server's host.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-p <replaceable>port</replaceable></option></term>
<term><option>--port=<replaceable class="parameter">port</replaceable></option></term>
<listitem>
<para>Database server's port.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-U <replaceable>username</replaceable></option></term>
<term><option>--username=<replaceable class="parameter">username</replaceable></option></term>
<listitem>
<para>User name to connect as.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-w</option></term>
<term><option>--no-password</option></term>
<listitem>
<para>
Never issue a password prompt. If the server requires password
authentication and a password is not available by other means
such as a <filename>.pgpass</filename> file, the connection
attempt will fail. This option can be useful in batch jobs and
scripts where no user is present to enter a password.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-W</option></term>
<term><option>--password</option></term>
<listitem>
<para>
Force <application>vacuumlo</application> to prompt for a
password before connecting to a database.
</para>
<para>
This option is never essential, since
<application>vacuumlo</application> will automatically prompt
for a password if the server demands password authentication.
However, <application>vacuumlo</application> will waste a
connection attempt finding out that the server wants a password.
In some cases it is worth typing <option>-W</option> to avoid the extra
connection attempt.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect1>
<refsect1>
<title>Environment</title>
<variablelist>
<varlistentry>
<term><envar>PGHOST</envar></term>
<term><envar>PGPORT</envar></term>
<term><envar>PGUSER</envar></term>
<listitem>
<para>
Default connection parameters.
</para>
</listitem>
</varlistentry>
</variablelist>
<para>
This utility, like most other <productname>PostgreSQL</productname> utilities,
also uses the environment variables supported by <application>libpq</application>
(see <xref linkend="libpq-envars"/>).
</para>
<para>
The environment variable <envar>PG_COLOR</envar> specifies whether to use
color in diagnostic messages. Possible values are
<literal>always</literal>, <literal>auto</literal> and
<literal>never</literal>.
</para>
</refsect1>
<refsect1>
<title>Notes</title>
<para>
<application>vacuumlo</application> works by the following method:
First, <application>vacuumlo</application> builds a temporary table which contains all
of the OIDs of the large objects in the selected database. It then scans
through all columns in the database that are of type
<type>oid</type> or <type>lo</type>, and removes matching entries from the temporary
table. (Note: Only types with these names are considered; in particular,
domains over them are not considered.) The remaining entries in the
temporary table identify orphaned LOs. These are removed.
</para>
</refsect1>
<refsect1>
<title>Author</title>
<para>
Peter Mount <email>peter@retep.org.uk</email>
</para>
</refsect1>
</refentry>
|
