How many ProcessInstance can run at the same time

For Flowable 7.0 open source BPMN engine, each request on ACT_RE_PROCDEF will create a ProcessInstance/task record in ACT_RU_TASK. How many ProcessInstance can run at the same time? Where can I find out this info?

There are no official benchmarks for 7.0 yet and performance highly depends on various factors. The question you are asking depends mainly on:

• the used database technology
• the sizing of the database server
• the additional information stored in every process instance, also including other activities like sequence flows
• the history level you have configured, since this increases the database size
• the way you are searching tasks and completing them
• ...

This list is certainly not complete and the only way to find out exact numbers is to do a benchmark for your specific use-case.

For performance in general there are a few benchmarks in the blog from Flowble. Those benchmarks have been performed with 6.3.0 which is already five years old. However, the general architecture of the BPMN engine is still the same and the major difference between 6.x and 7.x is described in this blog post.