Email Batch Size Field
Specifies the number of email messages that you want to process in one run of a job queue that has been set up to handle email logging. By default, the number of messages to process is 0, which means that email messages are not batched together. You can modify this value when you are fine tuning your process so that the execution of a job queue does not take too long. Any email message that is not logged in any particular run will be handled in a subsequent run that has been scheduled.