Readpast locking for queue processing

Readpast locking is an option that is available for the select and readtext commands and the data modification commands update, delete, and writetext. It instructs a command to silently skip all incompatible locks it encounters, without blocking, terminating, or generating a message. It is primarily used when the rows of a table constitute a queue. In such a case, a number of tasks may access the table to process the queued rows, which could, for example, represent queued customers or customer orders. A given task is not concerned with processing a specific member of the queue, but with processing any available members of the queue that meet its selection criteria.