vacuumlo
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## vacuumlo

vacuumlo — remove orphaned large objects from a PostgreSQL database

## Synopsis

`vacuumlo` [`option`...] `dbname`...

## Description

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.

## Options

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-run`

  Don't remove anything, just show what would be done.

`-v`
`--verbose`

  Write a lot of progress messages.

`-V`
`--version`

  Print the vacuumlo version and exit.

`-?`
`--help`

  Show help about vacuumlo command line arguments, and exit.

vacuumlo also accepts the following command-line arguments for connection parameters:

`-h `host``
`--host=`host``

  Database server's host.

`-p `port``
`--port=`port``

  Database server's port.

`-U `username``
`--username=`username``

  User 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`
`--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.

## Environment

`PGHOST`
`PGPORT`
`PGUSER`

  Default 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`.

## Notes

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.

## Author

Peter Mount `<peter@retep.org.uk>`

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