Limit the number of entries in map of signals for dedup purpose

[dhiaayachi]

Currently, mutable state maintain a map of signals with request_id as their keys and used it for dedup purpose. When the signal is coming from external (like received from SignalWorkflow API), those request_id stay in the map forever and never get cleaned up. We need to put some limit so this map does not grow unbounded, for example simple count limit or TTL based solution would work.

[dhiaayachi]

Thank you for reporting this issue. This is a known issue that can lead to unbounded growth in mutable state.

We are currently working on a solution for this issue and will provide updates as they become available. In the meantime, you can work around this issue by implementing a custom signal deduplication mechanism in your workflow code.

Here are some resources that may be helpful:

• SignalWorkflow API
• Mutable State

Please let us know if you have any other questions.

[dhiaayachi]

Thank you for reporting this issue.

The MutableState in Temporal currently maintains a map of signals with request_id as their keys for deduplication purposes. This map can grow unbounded as signals from external sources (like the SignalWorkflow API) are received.

We understand the need for a solution to limit the size of this map. We are currently working on solutions to address this issue.

In the meantime, you can consider using the following workarounds:

• Limit the number of signals received from external sources. You can implement a mechanism to prevent an unbounded number of signals from being sent to your workflow.
• Regularly clean up the MutableState map. You can implement a custom cleanup logic that periodically removes entries from the MutableState map, either based on a count limit or a TTL.

We appreciate your feedback and will update you as we make progress on this issue.