vacuumlo
vacuumlo — remove orphaned large objects from aPostgres Pro database
Synopsis
vacuumlo [option...]dbname...
Description
vacuumlo is a simple utility program that will remove any“orphaned” large objects from aPostgres Pro database. An orphaned large object (LO) is considered to be any LO whose OID does not appear in anyoid orlo data column of the database.
If you use this, you may also be interested in thelo_manage trigger in thelo 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:
-llimit--limit=limitRemove no more than
limitlarge objects per transaction (default 1000). Since the server acquires a lock per LO removed, removing too many LOs in one transaction risks exceedingmax_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 thevacuumlo version and exit.
-?--helpShow help aboutvacuumlo command line arguments, and exit.
vacuumlo also accepts the following command-line arguments for connection parameters:
-hhost--host=hostDatabase server's host.
-pport--port=portDatabase server's port.
-Uusername--username=usernameUser name to connect as.
-w--no-passwordNever issue a password prompt. If the server requires password authentication and a password is not available by other means such as a
.pgpassfile, 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--passwordForcevacuumlo to prompt for a password before connecting to a database.
This option is never essential, sincevacuumlo 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
-Wto avoid the extra connection attempt.
Environment
PGHOSTPGPORTPGUSERDefault connection parameters.
This utility, like most otherPostgres Pro utilities, also uses the environment variables supported bylibpq (seeSection 32.15).
The environment variablePG_COLOR specifies whether to use color in diagnostic messages. Possible values arealways,auto andnever.
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 typeoid orlo, 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>