Principle:Fede1024 Rust rdkafka Message Ownership Transfer
| Knowledge Sources | |
|---|---|
| Domains | Messaging, Memory_Management |
| Last Updated | 2026-02-07 19:00 GMT |
Overview
A pattern for converting zero-copy borrowed messages into heap-allocated owned messages that can be transferred across task boundaries.
Description
Message Ownership Transfer addresses a fundamental tension in high-performance messaging: zero-copy message access is fast but ties the message to the consumer's internal buffer lifetime, while cross-task transfer requires messages that own their data.
BorrowedMessage provides zero-copy access to message data within the consumer's internal event buffer. However, this data cannot outlive the consumer's buffer or be sent to another thread/task. The detach() method allocates new heap memory and copies the message fields (payload, key, topic, timestamp, partition, offset, headers) into an OwnedMessage that can be freely moved across task/thread boundaries.
Usage
Use this principle when you need to send a consumed message to another async task, a blocking thread, or store it for later processing. The typical pattern is: consume a BorrowedMessage, call detach() to get an OwnedMessage, and pass the owned version to the target task.
Theoretical Basis
This is an application of the Borrowed/Owned duality pattern common in Rust:
Pseudo-code logic:
// Abstract algorithm
borrowed_msg = consumer.recv() // zero-copy, tied to consumer lifetime
owned_msg = borrowed_msg.detach() // heap allocate, free to move
spawn(async move {
process(owned_msg) // can use in another task
})
The trade-off is explicit: zero-copy for hot-path inline processing, heap allocation only when cross-boundary transfer is needed.