https://drill.apache.org/apidocs/org/apache/drill/exec/expr/fn/impl/gaggr/CountFunctions.RepeatedDictCountFunction.html
CountFunctions.RepeatedDictCountFunction (Drill : 1.22.0 API)
declaration: package: org.apache.drill.exec.expr.fn.impl.gaggr, class: CountFunctions, class: RepeatedDictCountFunction
drillapi