Chapter 16. Locking and Concurrency
Locking Data
Lock Attributes
Avoiding Locks
Claims and Drains
Escalation and Promotion
It would be easy to have one process simply lock all the data while using it, but that of course would lead to other applications being unable to access the data during this time. Concurrency, the ability for multiple applications to access the same data at the same time, needs to be allowed but also controlled so that we prevent lost updates, access to uncommitted data, and unrepeatable reads (data changing between reads).
A balance must be achieved for maximum concurrency of all processes. There are many controls in DB2 to allow us to achieve maximum concurrency while maintaining the integrity of our data. These range from ...
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