[DRILL-335] Implement hash aggregation operator for grouped aggregation

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.4.0
• Assignee: Aman Sinha
• Reporter: Aman Sinha
• Created: 20/Dec/13 21:32
• Updated: 31/Jul/14 06:33
• Resolved: 23/Mar/14 02:05

Description

Placeholder for doing design and implementation of hash based aggregation in Drill. Currently, it supports sort based aggregation. Hash aggregation involves building a hash table on the grouping columns and maintaining workspace for each of the aggregate functions in the query. This issue will focus on non-distinct aggregation for now (i.e aggregate function does not contain DISTINCT). A separate issue will be created to track distinct aggregation.