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# InMemory Persistence
The InMemory persistence service provides a volatile storage, i.e. it is cleared on shutdown.
Because of that the restoreOnStartup strategy is not supported for this service.
The main use-case is to store data that is needed during runtime, e.g. temporary storage of forecast data that is retrieved from a binding.
Since all data is stored in memory only, there is no default strategy for this service. Unlike other persistence services, you MUST add a configuration, otherwise no data will be persisted. To avoid excessive memory usage, it is recommended to persist only a limited number of items and use a strategy that stores only data that is actually needed.
The service has a global configuration option maxEntries to limit the number of datapoints per item, the default value is 512.
When the number of datapoints is reached and a new value is persisted, the oldest (by timestamp) value will be removed.
A maxEntries value of 0 disables automatic purging.