Drill leverages LoadingCache in hive metastore client, in order to avoid the long access time to hive metastore server. However, there is a tradeoff between caching stale data and the possibility of cache hit.
DRILL-3893 changes cache invalidation policy to "1 minute after last write", to avoid the chances of hitting stale data. However, it also implies that the cached data would be only valid for 1 minute after loading/write.
It's desirable to allow user to configure the caching policy, per their individual use case requirement. In particular, we probably should allow user to specify:
1) caching invalidation policy : expire after last access, or expire after last write.
2) cache TTL.