If you are using database logging then it is possible to quickly build up a large number of entries in the Logs table. This option allows you to specify how many of these entries are kept. If you set this option to a number greater than zero then that number is used to determine the maximum number of rows, less than or equal to zero indicates no limit and is not recommended. You can also set this value to time values such as '<n> day' which will limit the log entries to those newer than that time. You can specify 'hour', 'day', 'week', 'month' and 'year', note that the values should be singular (no 's' at the end). The Logs table is pruned periodically so it is possible for more than the expected number of rows to be present briefly in the meantime.