Module partial_group 

Distributed GROUP BY for document queries.

Each shard computes local partial aggregates per group key. The coordinator merges partials across shards to produce the global result.

Example: SELECT status, COUNT(*), AVG(age) FROM users GROUP BY status

• Each shard returns: [("active", count=50, sum_age=1500, count_age=50), ...]
• Coordinator merges: ("active", count=150, avg_age=sum_ages/count_ages)

Structs

PartialColumnAgg

Partial aggregate state for a single column within a group.

PartialGroup

A partial aggregate for one group key from one shard.

PartialGroupByMerger

Merger for distributed GROUP BY results.