|
strong |
The clear history policy specifies when a reader or writer clears its sample history.
The policy applies each time a sample is added to a history: a writer adds a sample to its history when it writes the sample, and a reader adds a sample to its history when it receives it, either as a new sample or as part of the initial samples received when the reader attaches to a writer. The writer also applies the clear history policy of an attaching reader to its own history to select the initial samples it sends to this reader.
| Enumerator | |
|---|---|
| OnAdd | Clear the sample history when a SampleEvent::Add sample is added to the history. |
| OnRemove | Clear the sample history when a SampleEvent::Remove sample is added to the history. |
| OnAll | Clear the sample history when a new sample is added to the history. |
| OnAllExceptPartialUpdate | Clear the sample history when a new sample which is not a SampleEvent::PartialUpdate sample is added to the history. |
| Never | Never clear the sample history. Only Config::sampleCount and Config::sampleLifetime then bound the history, and both are unbounded by default: with the defaults, a writer accumulates every sample it publishes and a reader accumulates every sample the application has not yet read, for as long as the element lives. Set Config::sampleCount or Config::sampleLifetime on a long-lived element that writes or receives a high volume of samples. |
1.17.0 