The following problem does not exist in WebSphere eXtreme Scale version 7.0 and later. eXtreme Scale 7.0 solved the problem of writing data to a database out of order. The problem applies only to eXtreme Scale pre-7.0. The solution to this problem is left in as an example of using "soft references" to other objects and it remains a useful technique. We've seen that each BackingMap has its own instance of a Loader. Because each BackingMap uses the Loader to sync with the database according to its own conditions, we end up with different BackingMaps syncing at different times. Most of the time, we expect this to be a good thing. There are only four BackingMaps in our application that sync with the database (as seen below), but a larger application can have many more. Letting the BackingMaps sync on their own schedules reduces peak database load from an ObjectGrid instance.
Our PaymentProcessor application should be pretty fast again after enabling write-behind on the...