Database Strategies: Using Informix XPS and DB2 Universal Database

308 XPS to DB2

10.1 Tasks and activities

Typical transition planning tasks includes planning for activities that occur even

before actually moving the data. For example, it might be a good time to consider

architectural or structural changes you’ve thought about. However, take caution.

Making multiple major changes during a transition exposes you to the potential

for increased and over complex, issues. If time is on your side, it is typically

better to only make one change at a time. Some of typical steps to consider are:

򐂰 A readiness assessment

򐂰 Tool evaluation and selection

򐂰 Defining the scope of the project and the process steps

򐂰 Estimating durations of the process steps

򐂰 Planning the project

򐂰 Allocating resources

Each project is different, but there are some factors that are good indicators of

the overall effort. For instance, for applications that frequently use stored

procedures, the number and complexity of the stored procedures to be converted

greatly affect the length of the application transition. Another area might be the

use of times and dates. Each DBMS has different internal format and display

techniques. Physical requirements, such as the use of raw and cooked disk

areas, spaces, and nodes, can also represent a large amount of work, especially

as data grows significantly over time.

A transition plan can be as simple as a spreadsheet that lists the primary tasks

along with some of the associated information for each task - such as start date,

end date, elapsed time, dependencies, and who is responsible. There are also

project planning tools available that are specifically designed to plan and track

projects. These tools let you assign tasks, establish dependencies among the

various steps (for instance, you cannot start testing until you move the database

structure and the test data), and chart the original plan against what in-process

and completed activities.

10.1.1 Readiness assessment and scope

Planning a transition project begins with an assessment of the environment, the

size of the project, and an understanding of the resources that can be used.

An accurate profile of the system architecture is key to success. The following is

a list of some of the considerations that require attention:

򐂰 What characterizes the workload type mix: standardized reports or ad-hoc?

򐂰 What languages are used for the applications? For example, Java, C, C++,

and Visual Basic.