vacuumlo — remove orphaned large objects from a PostgreSQL database
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
lo data column
of the database.
If you use this, you may also be interested in the
lo_manage trigger in the
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:
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.
Don't remove anything, just show what would be done.
Write a lot of progress messages.
Print the vacuumlo version and exit.
Show help about vacuumlo command line arguments, and exit.
vacuumlo also accepts the following command-line arguments for connection parameters:
Database server's host.
Database server's port.
User name to connect as.
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.
Force 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
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
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.
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