1.4 KiB
1.4 KiB
Frequently Asked Questions (FAQ)
Stream Modality
Questions related to stream modality (e.g., MultiStreamTracker).
What is the impact of transitioning my KCL app from single-stream to multi-stream?
This answer assumes the StreamTracker implementation is being changed.
From KCL's perspective, there is no modality change by decreasing a multi-stream tracker from N streams to 1 stream.
The DDB leaseKey, used to persist metadata including lease checkpoint, has a modality-dependent format:
| Modality | leaseKey Format |
|---|---|
| single-stream | <shardId> |
| multi-stream | <accountId>:<streamName>:<streamCreationTimestamp>:<shardId> |
Transitioning an app -- either from single- to multi-, or vice versa -- creates a backwards-incompatible expectation on the leaseKey.
As a result, a KCL app will be blind to any leaseKey, and its checkpoint, that does not match the expected format.
Resources
For additional information, please consider reading: