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 because they entail a lot of different configuration...