Compaq Reliable Transaction Router manual Transaction Integrity, Flexibility and Growth

Flexibility and Growth

•User access patterns

•The volume of data

Since an RTR-based system can be built using multiple systems at each functional layer, it easily lends itself to step-by-step growth, avoiding unused capacity at each stage. With your system still up and running, it is possible to:

•Create and delete concurrent server processes.

•Add or remove nodes (frontend, router or backend).

This means you do not need to provide spare capacity to allow for growth.

RTR also allows parallel execution. This means that different parts of a single transaction can be processed in parallel by multiple servers.

RTR provides a comprehensive set of monitoring tools to help you evaluate the volume of traffic passing through the system. This can help you respond to unexpected load changes by altering the system configuration dynamically.

Transaction Integrity

RTR greatly simplifies the design and coding of distributed applications, because, with RTR, database actions can be bundled together into transactions.

To ensure that your application deals with transactions correctly, its transactions must be:

•Atomic

•Consistent

•Isolated

•Durable

These are the ACID properties of transactions. For more detail on these properties, see the Reliable Transaction Router Application Design Guide.

2–4Architectural Concepts