Tandem Capacity Model (TCM) Manual

In contrast to the batch transaction or workload is the online transaction. The online transaction or
workload is an open system. In contrast to batch transactions, the interval time of consecutive OLTP
transactions is random.
Although batch and online transactions are very different, query transactions are modeled as batch
or online transactions, depending on the CPU demand of the query transaction. Large demand
queries are modeled as batch. Small demand queries are modeled as OLTP.
Batch Examples
Consider the following examples of batch transactions.
International Bigbank runs a batch application that updates credit card balances nightly. The
application has a single batch transaction. The batch transaction updates International Bigbank’s
database consisting of 10,000 credit card records. The batch application processes an average
of 10,000 transactions per night. In this case, TCM has one batch transaction for the application.
That batch transaction has one task, and that single task has 10,000 smaller transactions.
Mighty Manufacturing company has a batch application called Shipping Orders. The application
currently has 20 tasks. Each task includes all the shipping orders received during that half of the
day, typically 10 orders in the morning and 15 orders in the afternoon. In this case, TCM has one
batch transaction for the application. Because all of these orders are the same shipping order
transaction, we can model them as one type of batch transaction — the shipping order transaction.
Within TCM, we can indicate that it is a batch transaction composed of 2 tasks, each task with
an average of 12.5 smaller transactions per task:
98 Modeling Batch Workloads