Specifies the maximum number of users allowed to access the
    database at one time. The default is 50 users. After the maximum
    is reached, the next user who tries to invoke the database
    receives an error message and must wait. The maximum number of
    users you can specify is 16368, and the minimum is 1 user.

    Note that "number of users" is defined as the number of active
    attachments to the database. Thus, if a single process runs
    one program but that program performs 12 attach operations, the
    process is responsible for 12 active users as defined by this
    argument.