Improve cache (#7227)
Improve cache (#7227)

* Improve cache

* Improve code, add docs

* Simplify flow

* Update docstring

apache/incubator-superset,airbnb/superset,zhouyao1994/incubator-superset,zhouyao1994/incubator-superset,mistercrunch/panoramix,airbnb/caravel,airbnb/superset,apache/incubator-superset,zhouyao1994/incubator-superset,airbnb/caravel,airbnb/caravel,zhouyao1994/incubator-superset,mistercrunch/panoramix,apache/incubator-superset,zhouyao1994/incubator-superset,mistercrunch/panoramix,airbnb/superset,apache/incubator-superset,apache/incubator-superset,airbnb/caravel,mistercrunch/panoramix,airbnb/superset