Information Technology Reference
In-Depth Information
Chapter 8. Implementing Persistence and
Transactions
In real-life scenarios, we need to have process instances running for many hours, days, or
even years. If we want to be able to run processes for such a long time, we cannot rely on
something as volatile as the memory of a server to keep track of all our process instances
statuses. We need a way to provide persistence for them.
This chapter focuses on providing a persistence and transaction mechanism to our process
engine environment, which will allow us to store enough information about our executions
to be able to recreate them afterwards. This feature brings the possibility of having more
than one thread or server trying to access the same persisted runtime environment at the
same time. So, we will also learn how to generate a transaction around said persistence to
make sure no concurrency issues occur.
Persistence and transactions are topics that are hard to handle for newcomers, mostly be-
cause they entail a lot of different configuration points that need to be carefully orches-
trated to get the expected behavior from our application. Once you have finished this
chapter, you will learn about the following:
• How the jBPM6 persistence works
• How to configure all the different components of the persistence and transaction
• Why we need transactions in our systems
