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
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:
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
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
.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 attempt.
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
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