Root process managing worker lifecycle
Languages / Knowledge library
Erlang
otp processes message passing and fault tolerance
Why learn Erlang?
Useful for long-lived concurrent services. Supervision and process isolation help structure recovery, but application invariants still require tests.
Where it came from
Erlang originated at Ericsson for building distributed, fault-tolerant systems. Erlang/OTP combines the language with runtime facilities, libraries, and reusable system behaviors.
Build your understanding
Work through these exercises in order. Try the task before opening a reference.
- Define a function using pattern matching.
- Send a message between two processes.
- Represent a worker using an OTP behavior.
- Place a worker under a supervisor.
- Test restart behavior after an intentional worker failure.
Documentation and sources
- Official project documentation (www.erlang.org)
Catalog research notes
- Research snapshot: September 9, 2026. This entry summarizes the linked primary documentation; it does not assert a latest release version.
Connect the ideas
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Real World Example
Distributed Sensor Aggregation for Smart Grids
A regional smart grid operator managing thousands of remote energy sensors.
The business problem
Individual sensor nodes frequently lose connectivity or crash due to environmental interference, causing cascading failures in the central monitoring system.
How this topic solves it
Utilizing Erlang/OTP processes, the system isolates each sensor connection into a lightweight, independent process. By employing supervision trees, the system detects process termination and automatically restarts failed handlers, ensuring that a single sensor crash does not impact the broader grid monitoring capability.
- Define a supervisor process to monitor worker processes assigned to specific sensor IDs.
- Implement worker processes using gen_server to handle incoming telemetry data via asynchronous message passing.
- Configure restart strategies within the supervisor to handle transient network errors.
- Use link or monitor primitives to establish fault-tolerant relationships between the supervisor and worker nodes.
This diagram illustrates how a supervisor manages individual sensor workers to ensure system stability.
Handles Sensor A telemetry
Handles Sensor B telemetry
External data source
- Supervisor → supervises → Worker 1
- Supervisor → supervises → Worker 2
- Sensor A → sends data → Worker 1
Expected business outcome
The monitoring system achieves high availability where individual sensor failures are contained and recovered without manual intervention or system-wide downtime.
Limitations and checks
The primary trade-off is memory overhead; while Erlang processes are lightweight, spawning millions of processes for high-frequency granular data can lead to significant heap consumption. You can check this by monitoring the process count and memory usage via the erlang:memory/0 function.