| Type: | integer |
| Default: | -1 (-1) |
| Min: | -1 (-1) |
| Max: | 2147483647 (2147483647kB) |
| Unit: | KB |
| Context: | superuser |
| Restart: | false |
| Since: | 9.2 |
Specifies the maximum amount of disk space that a process can use for temporary files, such as sort and hash temporary files, or the storage file for a held cursor. A transaction attempting to exceed this limit will be canceled. If this value is specified without units, it is taken as kilobytes. -1 (the default) means no limit. Only superusers can change this setting.
This setting constrains the total space used at any instant by all temporary files used by a given PostgreSQL process. It should be noted that disk space used for explicit temporary tables, as opposed to temporary files used behind-the-scenes in query execution, does not count against this limit.
Recommendations
… or something which is bigger than your largest possible sort, but not big enough to run you out of disk space.