Okay, I have huge set of records in a Custom object and i'm fetching these to do some kind of DML operations. During this batch process, how exactly does the records are fetched as in what order and what are the factors taken into consideration. Also, I would like to know if the newly added rows while batch is in progress would also be fetched ? If not, it doesn't really make sense that I am working on ALL the records present in the Custom object.
Please refer to the following link https://www.salesforce.com/us/developer/docs/apexcode/Content/apex_batch_interface.htm
Could you please explain what is being fetched and how it is going to effect your activities, we can schedule batch apex on hourly basis - Schedule Hourly Batch Using Cron Expression - Start on Abritrary Day of Month
or we can trigger batch apex on any dml operation - https://developer.salesforce.com/forums/ForumsMain?id=906F00000008zNcIAI