TMF Introduction (G06.26+)

Application Performance
HP NonStop TMF Introduction—522414-002
4-2
Performance Versus Transaction Size
Without TMF protection, the relative cost for input/output (I/O) operations per
transaction increases in direct proportion to the number of I/O operations in the
transaction. With TMF protection, the relative cost increases only slightly as the
number of I/O operations per transaction increases.
Performance Versus Transaction Size
The number of records being accessed in a transaction determines the transaction
size. The smallest transaction reads and updates one record. The largest transaction
could read and update all records in several files. A typical transaction reads and
updates one or several records in a number of files.
For example, filling out the bill of materials for rocket engines represents large
transactions, updating records for many parts in multiple files, charging the work to
various accounts, and scheduling. As shown in Figure 4-2, the inventory resides in
tables (files) distributed across many volumes; the scheduling and accounting data
reside on remote systems.
Another example is a bank buying an interest-bearing bond. This purchase is a
smaller transaction that could involve charging principal and accrued interest to
separate accounts, and then crediting the total cost to the brokerage firm from which
the bond was purchased.
Figure 4-2. Transaction Input/Output Example
Audit
Trail
Inventory Inventory Inventory
Bills of Materials
Transaction
Audit
Trail
Schedule
\SCHED
\MANUF
Audit
Trail
Accounts
\ACT
VST020.vsd