Module cross_partition 

Lock-free cross-partition aggregate store. Cross-partition aggregate store backed by papaya::HashMap.

In a partition-parallel system, each partition computes partial aggregates independently. The CrossPartitionAggregateStore provides a lock-free concurrent hash map where partitions publish their partial aggregates and readers can merge them on demand.

Design

• Each partition writes its partial aggregate under (group_key, partition_id)
• Readers iterate all partitions for a given group key and merge
• The underlying papaya::HashMap is lock-free and scales with readers

Thread Safety

All operations are Send + Sync. Writers use pin() + insert(); readers use pin() + get(). No external locking required.

Structs

CrossPartitionAggregateStore

Lock-free concurrent store for cross-partition partial aggregates.