Availability Guide for Application Design

Data Protection and Recovery
Availability Guide for Application Design—525637-004
4-27
Solution Using Low-Priority Transaction Processing
to Perform the Batch Function
When to Use This Approach
Running batch operations as low-level transactions works well for batch operations that
require read/write access.
One example of a task that might fit this approach well is the combination of two
separate database systems into one as a part of a corporate restructuring or takeover.
This method is particularly suited to this type of task if the data being merged is to be
loaded from tape or needs to be converted from one database format to another.
The load operation can run in parallel with online operations on the target system. It
can be done incrementally or all at once. Production application downtime is practically
eliminated by this method.
How Low-Priority Transaction Processing Works
Batch-type transactions are held in a queue of pending transactions that a background
application works on and updates the database from. Meanwhile, a server process
(with a higher priority) processes the online operations. The database does not
distinguish between the two sources. Batch operations are thus transformed into an
Figure 4-9. Concurrent Batch and Online Activity
Server
High-Priority OLTP Server
Class
Server
Batch Server
Class Running
in the Background
Online
Transaction
Requester
Pending
Transactions
Database of
Record
Batch-type
Transactions
Utility
Requesters
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