[CALCITE-2101] Druid adapter: Push count(column) using Druid filtered aggregate

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.16.0
• Component/s: druid-adapter
• Assignee: Slim Bouguerra
• Reporter: Slim Bouguerra
• Created: 19/Dec/17 21:41
• Updated: 17/Mar/18 17:43
• Resolved: 20/Dec/17 21:20

Description

We can make use of newly added filtered aggregate (ie org.apache.calcite.adapter.druid.DruidQuery.JsonFilteredAggregation) and push down Count(column) as

 Count(*) where column is not Null