doc/src/sgml/vacuumlo.sgml

   1 <!-- $PostgreSQL$ -->
   2
   3 <sect1 id="vacuumlo">
   4  <title>vacuumlo</title>
   5
   6  <indexterm zone="vacuumlo">
   7   <primary>vacuumlo</primary>
   8  </indexterm>
   9
  10  <para>
  11   <application>vacuumlo</> is a simple utility program that will remove any
  12   <quote>orphaned</> large objects from a
  13   <productname>PostgreSQL</> database.  An orphaned large object (LO) is
  14   considered to be any LO whose OID does not appear in any <type>oid</> or
  15   <type>lo</> data column of the database.
  16  </para>
  17
  18  <para>
  19   If you use this, you may also be interested in the <function>lo_manage</>
  20   trigger in <filename>contrib/lo</> (see <xref linkend="lo">).
  21   <function>lo_manage</> is useful to try
  22   to avoid creating orphaned LOs in the first place.
  23  </para>
  24
  25  <sect2>
  26   <title>Usage</title>
  27
  28   <synopsis>
  29 vacuumlo [options] database [database2 ... databaseN]
  30   </synopsis>
  31
  32   <para>
  33    All databases named on the command line are processed.  Available options
  34    include:
  35   </para>
  36
  37   <variablelist>
  38    <varlistentry>
  39     <term><option>-v</option></term>
  40     <listitem>
  41      <para>Write a lot of progress messages.</para>
  42     </listitem>
  43    </varlistentry>
  44
  45    <varlistentry>
  46     <term><option>-n</option></term>
  47     <listitem>
  48      <para>Don't remove anything, just show what would be done.</para>
  49     </listitem>
  50    </varlistentry>
  51
  52    <varlistentry>
  53     <term><option>-U</option> <replaceable>username</></term>
  54     <listitem>
  55      <para>Username to connect as.</para>
  56     </listitem>
  57    </varlistentry>
  58
  59    <varlistentry>
  60     <term><option>-w</></term>
  61     <term><option>--no-password</></term>
  62     <listitem>
  63      <para>
  64       Never issue a password prompt.  If the server requires password
  65       authentication and a password is not available by other means
  66       such as a <filename>.pgpass</filename> file, the connection
  67       attempt will fail.  This option can be useful in batch jobs and
  68       scripts where no user is present to enter a password.
  69      </para>
  70     </listitem>
  71    </varlistentry>
  72
  73    <varlistentry>
  74     <term><option>-W</option></term>
  75     <listitem>
  76      <para>
  77       Force <application>vacuumlo</application> to prompt for a
  78       password before connecting to a database.
  79      </para>
  80
  81      <para>
  82       This option is never essential, since
  83       <application>vacuumlo</application> will automatically prompt
  84       for a password if the server demands password authentication.
  85       However, <application>vacuumlo</application> will waste a
  86       connection attempt finding out that the server wants a password.
  87       In some cases it is worth typing <option>-W</> to avoid the extra
  88       connection attempt.
  89      </para>
  90     </listitem>
  91    </varlistentry>
  92
  93    <varlistentry>
  94     <term><option>-h</option> <replaceable>hostname</></term>
  95     <listitem>
  96      <para>Database server's host.</para>
  97     </listitem>
  98    </varlistentry>
  99
 100    <varlistentry>
 101     <term><option>-p</option> <replaceable>port</></term>
 102     <listitem>
 103      <para>Database server's port.</para>
 104     </listitem>
 105    </varlistentry>
 106   </variablelist>
 107  </sect2>
 108
 109  <sect2>
 110   <title>Method</title>
 111
 112   <para>
 113    First, it builds a temporary table which contains all of the OIDs of the
 114    large objects in that database.
 115   </para>
 116
 117   <para>
 118    It then scans through all columns in the database that are of type
 119    <type>oid</> or <type>lo</>, and removes matching entries from the
 120   temporary table.
 121   </para>
 122
 123   <para>
 124    The remaining entries in the temp table identify orphaned LOs.
 125    These are removed.
 126   </para>
 127  </sect2>
 128
 129  <sect2>
 130   <title>Author</title>
 131
 132   <para>
 133    Peter Mount <email>peter@retep.org.uk</email>
 134   </para>
 135  </sect2>
 136
 137 </sect1>