Context and Problem
In systems that handle complex workflows, the order of operations is often critical to ensuring data consistency and the integrity of processes.
- Dependencies between tasks that must be executed in a certain order.
- Risk of inconsistencies when tasks are processed out of sequence.
- Difficulty in ensuring that all tasks complete in the required order.
Solution
The Sequential Convoy pattern ensures that tasks or messages are processed in the order required by the system, preventing race conditions and ensuring data consistency.
- Define the sequence in which tasks need to be processed.
- Use a queue or buffer to manage tasks that need to be processed in sequence.
- Ensure that each task is processed only after the previous one completes.
- Handle potential delays or failures in a way that doesn’t disrupt the sequence.
- Ensure that system resources are appropriately allocated to support the sequential processing.
Benefits
- Data consistency
- Ensures that tasks or operations are processed in the correct order, preserving data integrity.
- Process integrity
- Avoids errors or inconsistencies caused by out-of-order task execution.
- Predictability
- The system’s behavior becomes more predictable as tasks are executed in sequence.
Trade-offs
- Reduced throughput
- Sequential processing can slow down the system by waiting for tasks to complete in order.
- Increased latency
- Processing tasks one at a time increases the overall time to complete a workflow.
- Resource contention
- Sequential processing may cause resource contention if multiple tasks compete for the same resources.
Issues and Considerations
- Managing task ordering
- Ensuring that tasks are executed in the correct order and handling delays or failures in a way that doesn’t disrupt the process.
- Handling failures
- Dealing with failures in a way that doesn’t cause the entire sequence to fail.
- Performance impact
- Sequential processing may affect system performance due to waiting on each task to complete.
When to Use This Pattern
- When tasks need to be executed in a specific order to ensure correctness.
- When system integrity is dependent on maintaining an exact sequence of operations.
- When race conditions or inconsistencies can occur if tasks are processed out of order.