While working with the Pega Platform, We often get confused with the term THREAD [at least me 😅], especially while debugging using clipboard viewer/tracer else while writing asynchronous activities or managing service pooling.
Are those same? No 🤐, OS threads and threads in Pega are different. They are conceptually different and serve different purposes.
OS Threads (Operating System Threads):
These are threads managed by the operating system of the underlying hardware. When a program or application creates a thread, the operating system provides the necessary support for managing the thread's execution, scheduling, and resource allocation. OS threads are low-level constructs the operating system provides and are essential for enabling multitasking and concurrency in modern computer systems. Each OS thread typically corresponds to a separate execution context with its own stack and program counter.
All the rules are executed by Pega PRPC using a thread. 🤟
Threads in Pega:
In Pega, threads refer to the processing units that execute various tasks related to business processes.
In Pega, threads execute the tasks defined in the business processes. When a user interacts with a Pega application (e.g., submitting an assignment, or initiating a workflow), the system creates a thread to handle the processing of that particular work item. These threads are managed by the Pega platform and are distinct from OS threads.
Pega employs its own thread management and resource allocation mechanisms to efficiently handle and distribute the workload of business processes among available processing units. Pega threads work at a higher level of abstraction than OS threads, and their lifecycle and management are specific to the Pega application's workflow and rules. 🧠
In summary, One Pega thread might be invoking 10s or more threads to complete a Business unit process[Pega thread]. OS threads are managed by the operating system and provide low-level support for multitasking and concurrency, while threads in Pega are used to handle business process tasks and are managed at a higher level by the Pega platform.