vacuumlo — remove orphaned large objects from a PostgreSQL database
vacuumlo [option...]  dbname... 
  vacuumlo is a simple utility program that will remove any
  “orphaned” large objects from a
  PostgreSQL database.  An orphaned large object (LO) is
  considered to be any LO whose OID does not appear in any oid or
  lo data column of the database.
 
  If you use this, you may also be interested in the lo_manage
  trigger in the lo module.
  lo_manage is useful to try
  to avoid creating orphaned LOs in the first place.
 
All databases named on the command line are processed.
vacuumlo accepts the following command-line arguments:
-l limit--limit=limit
      Remove no more than limit large objects per
      transaction (default 1000).  Since the server acquires a lock per LO
      removed, removing too many LOs in one transaction risks exceeding
      max_locks_per_transaction.  Set the limit to
      zero if you want all removals done in a single transaction.
     
-n--dry-runDon't remove anything, just show what would be done.
-v--verboseWrite a lot of progress messages.
-V--versionPrint the vacuumlo version and exit.
-?--helpShow help about vacuumlo command line arguments, and exit.
vacuumlo also accepts the following command-line arguments for connection parameters:
-h host--host=hostDatabase server's host.
-p port--port=portDatabase server's port.
-U username--username=usernameUser name to connect as.
-w--no-password
      Never issue a password prompt.  If the server requires password
      authentication and a password is not available by other means
      such as a .pgpass 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.
     
-W--passwordForce vacuumlo to prompt for a password before connecting to a database.
      This option is never essential, since
      vacuumlo will automatically prompt
      for a password if the server demands password authentication.
      However, vacuumlo will waste a
      connection attempt finding out that the server wants a password.
      In some cases it is worth typing -W to avoid the extra
      connection attempt.
     
PGHOSTPGPORTPGUSERDefault connection parameters.
This utility, like most other PostgreSQL utilities, also uses the environment variables supported by libpq (see Section 34.15).
   The environment variable PG_COLOR specifies whether to use
   color in diagnostic messages. Possible values are
   always, auto and
   never.
  
   vacuumlo works by the following method:
   First, vacuumlo 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
   oid or lo, 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.
  
   Peter Mount <peter@retep.org.uk>