Introduce pre-caching for Constant LargeDataFeed #6
Description
- Constant should cache the item in-memory in hash-map with a bounded size limit
- If there is no item in the hash-map, then we fetch it from SQLite and set it in the hash-map
- The default size of hash-map could be 1K elements. It can be configured during the instance creation of Constant LargeDataFeed